Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost

[cris-mirror.git] / tools / perf / builtin-top.c

/*
 * builtin-top.c
 *
 * Builtin top command: Display a continuously updated profile of
 * any workload, CPU or specific PID.
 *
 * Copyright (C) 2008, Red Hat Inc, Ingo Molnar <mingo@redhat.com>
 *               2011, Red Hat Inc, Arnaldo Carvalho de Melo <acme@redhat.com>
 *
 * Improvements and fixes by:
 *
 *   Arjan van de Ven <arjan@linux.intel.com>
 *   Yanmin Zhang <yanmin.zhang@intel.com>
 *   Wu Fengguang <fengguang.wu@intel.com>
 *   Mike Galbraith <efault@gmx.de>
 *   Paul Mackerras <paulus@samba.org>
 *
 * Released under the GPL v2. (and only v2, not any later version)
 */
#include "builtin.h"

#include "perf.h"

#include "util/annotate.h"
#include "util/config.h"
#include "util/color.h"
#include "util/drv_configs.h"
#include "util/evlist.h"
#include "util/evsel.h"
#include "util/event.h"
#include "util/machine.h"
#include "util/session.h"
#include "util/symbol.h"
#include "util/thread.h"
#include "util/thread_map.h"
#include "util/top.h"
#include <linux/rbtree.h>
#include <subcmd/parse-options.h>
#include "util/parse-events.h"
#include "util/cpumap.h"
#include "util/xyarray.h"
#include "util/sort.h"
#include "util/term.h"
#include "util/intlist.h"
#include "util/parse-branch-options.h"
#include "arch/common.h"

#include "util/debug.h"

#include <assert.h>
#include <elf.h>
#include <fcntl.h>

#include <stdio.h>
#include <termios.h>
#include <unistd.h>
#include <inttypes.h>

#include <errno.h>
#include <time.h>
#include <sched.h>
#include <signal.h>

#include <sys/syscall.h>
#include <sys/ioctl.h>
#include <poll.h>
#include <sys/prctl.h>
#include <sys/wait.h>
#include <sys/uio.h>
#include <sys/utsname.h>
#include <sys/mman.h>

#include <linux/stringify.h>
#include <linux/time64.h>
#include <linux/types.h>

#include "sane_ctype.h"

static volatile int done;
static volatile int resize;

#define HEADER_LINE_NR  5

static void perf_top__update_print_entries(struct perf_top *top)
{
        top->print_entries = top->winsize.ws_row - HEADER_LINE_NR;
}

static void winch_sig(int sig __maybe_unused)
{
        resize = 1;
}

static void perf_top__resize(struct perf_top *top)
{
        get_term_dimensions(&top->winsize);
        perf_top__update_print_entries(top);
}

static int perf_top__parse_source(struct perf_top *top, struct hist_entry *he)
{
        struct perf_evsel *evsel = hists_to_evsel(he->hists);
        struct symbol *sym;
        struct annotation *notes;
        struct map *map;
        int err = -1;

        if (!he || !he->ms.sym)
                return -1;

        sym = he->ms.sym;
        map = he->ms.map;

        /*
         * We can't annotate with just /proc/kallsyms
         */
        if (map->dso->symtab_type == DSO_BINARY_TYPE__KALLSYMS &&
            !dso__is_kcore(map->dso)) {
                pr_err("Can't annotate %s: No vmlinux file was found in the "
                       "path\n", sym->name);
                sleep(1);
                return -1;
        }

        notes = symbol__annotation(sym);
        if (notes->src != NULL) {
                pthread_mutex_lock(&notes->lock);
                goto out_assign;
        }

        pthread_mutex_lock(&notes->lock);

        if (symbol__alloc_hist(sym) < 0) {
                pthread_mutex_unlock(&notes->lock);
                pr_err("Not enough memory for annotating '%s' symbol!\n",
                       sym->name);
                sleep(1);
                return err;
        }

        err = symbol__annotate(sym, map, evsel, 0, NULL);
        if (err == 0) {
out_assign:
                top->sym_filter_entry = he;
        } else {
                char msg[BUFSIZ];
                symbol__strerror_disassemble(sym, map, err, msg, sizeof(msg));
                pr_err("Couldn't annotate %s: %s\n", sym->name, msg);
        }

        pthread_mutex_unlock(&notes->lock);
        return err;
}

static void __zero_source_counters(struct hist_entry *he)
{
        struct symbol *sym = he->ms.sym;
        symbol__annotate_zero_histograms(sym);
}

static void ui__warn_map_erange(struct map *map, struct symbol *sym, u64 ip)
{
        struct utsname uts;
        int err = uname(&uts);

        ui__warning("Out of bounds address found:\n\n"
                    "Addr:   %" PRIx64 "\n"
                    "DSO:    %s %c\n"
                    "Map:    %" PRIx64 "-%" PRIx64 "\n"
                    "Symbol: %" PRIx64 "-%" PRIx64 " %c %s\n"
                    "Arch:   %s\n"
                    "Kernel: %s\n"
                    "Tools:  %s\n\n"
                    "Not all samples will be on the annotation output.\n\n"
                    "Please report to linux-kernel@vger.kernel.org\n",
                    ip, map->dso->long_name, dso__symtab_origin(map->dso),
                    map->start, map->end, sym->start, sym->end,
                    sym->binding == STB_GLOBAL ? 'g' :
                    sym->binding == STB_LOCAL  ? 'l' : 'w', sym->name,
                    err ? "[unknown]" : uts.machine,
                    err ? "[unknown]" : uts.release, perf_version_string);
        if (use_browser <= 0)
                sleep(5);

        map->erange_warned = true;
}

static void perf_top__record_precise_ip(struct perf_top *top,
                                        struct hist_entry *he,
                                        struct perf_sample *sample,
                                        int counter, u64 ip)
{
        struct annotation *notes;
        struct symbol *sym = he->ms.sym;
        int err = 0;

        if (sym == NULL || (use_browser == 0 &&
                            (top->sym_filter_entry == NULL ||
                             top->sym_filter_entry->ms.sym != sym)))
                return;

        notes = symbol__annotation(sym);

        if (pthread_mutex_trylock(&notes->lock))
                return;

        err = hist_entry__inc_addr_samples(he, sample, counter, ip);

        pthread_mutex_unlock(&notes->lock);

        if (unlikely(err)) {
                /*
                 * This function is now called with he->hists->lock held.
                 * Release it before going to sleep.
                 */
                pthread_mutex_unlock(&he->hists->lock);

                if (err == -ERANGE && !he->ms.map->erange_warned)
                        ui__warn_map_erange(he->ms.map, sym, ip);
                else if (err == -ENOMEM) {
                        pr_err("Not enough memory for annotating '%s' symbol!\n",
                               sym->name);
                        sleep(1);
                }

                pthread_mutex_lock(&he->hists->lock);
        }
}

static void perf_top__show_details(struct perf_top *top)
{
        struct hist_entry *he = top->sym_filter_entry;
        struct perf_evsel *evsel = hists_to_evsel(he->hists);
        struct annotation *notes;
        struct symbol *symbol;
        int more;

        if (!he)
                return;

        symbol = he->ms.sym;
        notes = symbol__annotation(symbol);

        pthread_mutex_lock(&notes->lock);

        symbol__calc_percent(symbol, evsel);

        if (notes->src == NULL)
                goto out_unlock;

        printf("Showing %s for %s\n", perf_evsel__name(top->sym_evsel), symbol->name);
        printf("  Events  Pcnt (>=%d%%)\n", top->sym_pcnt_filter);

        more = symbol__annotate_printf(symbol, he->ms.map, top->sym_evsel,
                                       0, top->sym_pcnt_filter, top->print_entries, 4);

        if (top->evlist->enabled) {
                if (top->zero)
                        symbol__annotate_zero_histogram(symbol, top->sym_evsel->idx);
                else
                        symbol__annotate_decay_histogram(symbol, top->sym_evsel->idx);
        }
        if (more != 0)
                printf("%d lines not displayed, maybe increase display entries [e]\n", more);
out_unlock:
        pthread_mutex_unlock(&notes->lock);
}

static void perf_top__print_sym_table(struct perf_top *top)
{
        char bf[160];
        int printed = 0;
        const int win_width = top->winsize.ws_col - 1;
        struct perf_evsel *evsel = top->sym_evsel;
        struct hists *hists = evsel__hists(evsel);

        puts(CONSOLE_CLEAR);

        perf_top__header_snprintf(top, bf, sizeof(bf));
        printf("%s\n", bf);

        perf_top__reset_sample_counters(top);

        printf("%-*.*s\n", win_width, win_width, graph_dotted_line);

        if (!top->record_opts.overwrite &&
            (hists->stats.nr_lost_warned !=
            hists->stats.nr_events[PERF_RECORD_LOST])) {
                hists->stats.nr_lost_warned =
                              hists->stats.nr_events[PERF_RECORD_LOST];
                color_fprintf(stdout, PERF_COLOR_RED,
                              "WARNING: LOST %d chunks, Check IO/CPU overload",
                              hists->stats.nr_lost_warned);
                ++printed;
        }

        if (top->sym_filter_entry) {
                perf_top__show_details(top);
                return;
        }

        if (top->evlist->enabled) {
                if (top->zero) {
                        hists__delete_entries(hists);
                } else {
                        hists__decay_entries(hists, top->hide_user_symbols,
                                             top->hide_kernel_symbols);
                }
        }

        hists__collapse_resort(hists, NULL);
        perf_evsel__output_resort(evsel, NULL);

        hists__output_recalc_col_len(hists, top->print_entries - printed);
        putchar('\n');
        hists__fprintf(hists, false, top->print_entries - printed, win_width,
                       top->min_percent, stdout, symbol_conf.use_callchain);
}

static void prompt_integer(int *target, const char *msg)
{
        char *buf = malloc(0), *p;
        size_t dummy = 0;
        int tmp;

        fprintf(stdout, "\n%s: ", msg);
        if (getline(&buf, &dummy, stdin) < 0)
                return;

        p = strchr(buf, '\n');
        if (p)
                *p = 0;

        p = buf;
        while(*p) {
                if (!isdigit(*p))
                        goto out_free;
                p++;
        }
        tmp = strtoul(buf, NULL, 10);
        *target = tmp;
out_free:
        free(buf);
}

static void prompt_percent(int *target, const char *msg)
{
        int tmp = 0;

        prompt_integer(&tmp, msg);
        if (tmp >= 0 && tmp <= 100)
                *target = tmp;
}

static void perf_top__prompt_symbol(struct perf_top *top, const char *msg)
{
        char *buf = malloc(0), *p;
        struct hist_entry *syme = top->sym_filter_entry, *n, *found = NULL;
        struct hists *hists = evsel__hists(top->sym_evsel);
        struct rb_node *next;
        size_t dummy = 0;

        /* zero counters of active symbol */
        if (syme) {
                __zero_source_counters(syme);
                top->sym_filter_entry = NULL;
        }

        fprintf(stdout, "\n%s: ", msg);
        if (getline(&buf, &dummy, stdin) < 0)
                goto out_free;

        p = strchr(buf, '\n');
        if (p)
                *p = 0;

        next = rb_first(&hists->entries);
        while (next) {
                n = rb_entry(next, struct hist_entry, rb_node);
                if (n->ms.sym && !strcmp(buf, n->ms.sym->name)) {
                        found = n;
                        break;
                }
                next = rb_next(&n->rb_node);
        }

        if (!found) {
                fprintf(stderr, "Sorry, %s is not active.\n", buf);
                sleep(1);
        } else
                perf_top__parse_source(top, found);

out_free:
        free(buf);
}

static void perf_top__print_mapped_keys(struct perf_top *top)
{
        char *name = NULL;

        if (top->sym_filter_entry) {
                struct symbol *sym = top->sym_filter_entry->ms.sym;
                name = sym->name;
        }

        fprintf(stdout, "\nMapped keys:\n");
        fprintf(stdout, "\t[d]     display refresh delay.             \t(%d)\n", top->delay_secs);
        fprintf(stdout, "\t[e]     display entries (lines).           \t(%d)\n", top->print_entries);

        if (top->evlist->nr_entries > 1)
                fprintf(stdout, "\t[E]     active event counter.              \t(%s)\n", perf_evsel__name(top->sym_evsel));

        fprintf(stdout, "\t[f]     profile display filter (count).    \t(%d)\n", top->count_filter);

        fprintf(stdout, "\t[F]     annotate display filter (percent). \t(%d%%)\n", top->sym_pcnt_filter);
        fprintf(stdout, "\t[s]     annotate symbol.                   \t(%s)\n", name?: "NULL");
        fprintf(stdout, "\t[S]     stop annotation.\n");

        fprintf(stdout,
                "\t[K]     hide kernel symbols.             \t(%s)\n",
                top->hide_kernel_symbols ? "yes" : "no");
        fprintf(stdout,
                "\t[U]     hide user symbols.               \t(%s)\n",
                top->hide_user_symbols ? "yes" : "no");
        fprintf(stdout, "\t[z]     toggle sample zeroing.             \t(%d)\n", top->zero ? 1 : 0);
        fprintf(stdout, "\t[qQ]    quit.\n");
}

static int perf_top__key_mapped(struct perf_top *top, int c)
{
        switch (c) {
                case 'd':
                case 'e':
                case 'f':
                case 'z':
                case 'q':
                case 'Q':
                case 'K':
                case 'U':
                case 'F':
                case 's':
                case 'S':
                        return 1;
                case 'E':
                        return top->evlist->nr_entries > 1 ? 1 : 0;
                default:
                        break;
        }

        return 0;
}

static bool perf_top__handle_keypress(struct perf_top *top, int c)
{
        bool ret = true;

        if (!perf_top__key_mapped(top, c)) {
                struct pollfd stdin_poll = { .fd = 0, .events = POLLIN };
                struct termios save;

                perf_top__print_mapped_keys(top);
                fprintf(stdout, "\nEnter selection, or unmapped key to continue: ");
                fflush(stdout);

                set_term_quiet_input(&save);

                poll(&stdin_poll, 1, -1);
                c = getc(stdin);

                tcsetattr(0, TCSAFLUSH, &save);
                if (!perf_top__key_mapped(top, c))
                        return ret;
        }

        switch (c) {
                case 'd':
                        prompt_integer(&top->delay_secs, "Enter display delay");
                        if (top->delay_secs < 1)
                                top->delay_secs = 1;
                        break;
                case 'e':
                        prompt_integer(&top->print_entries, "Enter display entries (lines)");
                        if (top->print_entries == 0) {
                                perf_top__resize(top);
                                signal(SIGWINCH, winch_sig);
                        } else {
                                signal(SIGWINCH, SIG_DFL);
                        }
                        break;
                case 'E':
                        if (top->evlist->nr_entries > 1) {
                                /* Select 0 as the default event: */
                                int counter = 0;

                                fprintf(stderr, "\nAvailable events:");

                                evlist__for_each_entry(top->evlist, top->sym_evsel)
                                        fprintf(stderr, "\n\t%d %s", top->sym_evsel->idx, perf_evsel__name(top->sym_evsel));

                                prompt_integer(&counter, "Enter details event counter");

                                if (counter >= top->evlist->nr_entries) {
                                        top->sym_evsel = perf_evlist__first(top->evlist);
                                        fprintf(stderr, "Sorry, no such event, using %s.\n", perf_evsel__name(top->sym_evsel));
                                        sleep(1);
                                        break;
                                }
                                evlist__for_each_entry(top->evlist, top->sym_evsel)
                                        if (top->sym_evsel->idx == counter)
                                                break;
                        } else
                                top->sym_evsel = perf_evlist__first(top->evlist);
                        break;
                case 'f':
                        prompt_integer(&top->count_filter, "Enter display event count filter");
                        break;
                case 'F':
                        prompt_percent(&top->sym_pcnt_filter,
                                       "Enter details display event filter (percent)");
                        break;
                case 'K':
                        top->hide_kernel_symbols = !top->hide_kernel_symbols;
                        break;
                case 'q':
                case 'Q':
                        printf("exiting.\n");
                        if (top->dump_symtab)
                                perf_session__fprintf_dsos(top->session, stderr);
                        ret = false;
                        break;
                case 's':
                        perf_top__prompt_symbol(top, "Enter details symbol");
                        break;
                case 'S':
                        if (!top->sym_filter_entry)
                                break;
                        else {
                                struct hist_entry *syme = top->sym_filter_entry;

                                top->sym_filter_entry = NULL;
                                __zero_source_counters(syme);
                        }
                        break;
                case 'U':
                        top->hide_user_symbols = !top->hide_user_symbols;
                        break;
                case 'z':
                        top->zero = !top->zero;
                        break;
                default:
                        break;
        }

        return ret;
}

static void perf_top__sort_new_samples(void *arg)
{
        struct perf_top *t = arg;
        struct perf_evsel *evsel = t->sym_evsel;
        struct hists *hists;

        perf_top__reset_sample_counters(t);

        if (t->evlist->selected != NULL)
                t->sym_evsel = t->evlist->selected;

        hists = evsel__hists(evsel);

        if (t->evlist->enabled) {
                if (t->zero) {
                        hists__delete_entries(hists);
                } else {
                        hists__decay_entries(hists, t->hide_user_symbols,
                                             t->hide_kernel_symbols);
                }
        }

        hists__collapse_resort(hists, NULL);
        perf_evsel__output_resort(evsel, NULL);
}

static void *display_thread_tui(void *arg)
{
        struct perf_evsel *pos;
        struct perf_top *top = arg;
        const char *help = "For a higher level overview, try: perf top --sort comm,dso";
        struct hist_browser_timer hbt = {
                .timer          = perf_top__sort_new_samples,
                .arg            = top,
                .refresh        = top->delay_secs,
        };

        /* In order to read symbols from other namespaces perf to  needs to call
         * setns(2).  This isn't permitted if the struct_fs has multiple users.
         * unshare(2) the fs so that we may continue to setns into namespaces
         * that we're observing.
         */
        unshare(CLONE_FS);

        perf_top__sort_new_samples(top);

        /*
         * Initialize the uid_filter_str, in the future the TUI will allow
         * Zooming in/out UIDs. For now juse use whatever the user passed
         * via --uid.
         */
        evlist__for_each_entry(top->evlist, pos) {
                struct hists *hists = evsel__hists(pos);
                hists->uid_filter_str = top->record_opts.target.uid_str;
        }

        perf_evlist__tui_browse_hists(top->evlist, help, &hbt,
                                      top->min_percent,
                                      &top->session->header.env,
                                      !top->record_opts.overwrite);

        done = 1;
        return NULL;
}

static void display_sig(int sig __maybe_unused)
{
        done = 1;
}

static void display_setup_sig(void)
{
        signal(SIGSEGV, sighandler_dump_stack);
        signal(SIGFPE, sighandler_dump_stack);
        signal(SIGINT,  display_sig);
        signal(SIGQUIT, display_sig);
        signal(SIGTERM, display_sig);
}

static void *display_thread(void *arg)
{
        struct pollfd stdin_poll = { .fd = 0, .events = POLLIN };
        struct termios save;
        struct perf_top *top = arg;
        int delay_msecs, c;

        /* In order to read symbols from other namespaces perf to  needs to call
         * setns(2).  This isn't permitted if the struct_fs has multiple users.
         * unshare(2) the fs so that we may continue to setns into namespaces
         * that we're observing.
         */
        unshare(CLONE_FS);

        display_setup_sig();
        pthread__unblock_sigwinch();
repeat:
        delay_msecs = top->delay_secs * MSEC_PER_SEC;
        set_term_quiet_input(&save);
        /* trash return*/
        getc(stdin);

        while (!done) {
                perf_top__print_sym_table(top);
                /*
                 * Either timeout expired or we got an EINTR due to SIGWINCH,
                 * refresh screen in both cases.
                 */
                switch (poll(&stdin_poll, 1, delay_msecs)) {
                case 0:
                        continue;
                case -1:
                        if (errno == EINTR)
                                continue;
                        __fallthrough;
                default:
                        c = getc(stdin);
                        tcsetattr(0, TCSAFLUSH, &save);

                        if (perf_top__handle_keypress(top, c))
                                goto repeat;
                        done = 1;
                }
        }

        tcsetattr(0, TCSAFLUSH, &save);
        return NULL;
}

static int hist_iter__top_callback(struct hist_entry_iter *iter,
                                   struct addr_location *al, bool single,
                                   void *arg)
{
        struct perf_top *top = arg;
        struct hist_entry *he = iter->he;
        struct perf_evsel *evsel = iter->evsel;

        if (perf_hpp_list.sym && single)
                perf_top__record_precise_ip(top, he, iter->sample, evsel->idx, al->addr);

        hist__account_cycles(iter->sample->branch_stack, al, iter->sample,
                     !(top->record_opts.branch_stack & PERF_SAMPLE_BRANCH_ANY));
        return 0;
}

static void perf_event__process_sample(struct perf_tool *tool,
                                       const union perf_event *event,
                                       struct perf_evsel *evsel,
                                       struct perf_sample *sample,
                                       struct machine *machine)
{
        struct perf_top *top = container_of(tool, struct perf_top, tool);
        struct addr_location al;
        int err;

        if (!machine && perf_guest) {
                static struct intlist *seen;

                if (!seen)
                        seen = intlist__new(NULL);

                if (!intlist__has_entry(seen, sample->pid)) {
                        pr_err("Can't find guest [%d]'s kernel information\n",
                                sample->pid);
                        intlist__add(seen, sample->pid);
                }
                return;
        }

        if (!machine) {
                pr_err("%u unprocessable samples recorded.\r",
                       top->session->evlist->stats.nr_unprocessable_samples++);
                return;
        }

        if (event->header.misc & PERF_RECORD_MISC_EXACT_IP)
                top->exact_samples++;

        if (machine__resolve(machine, &al, sample) < 0)
                return;

        if (!machine->kptr_restrict_warned &&
            symbol_conf.kptr_restrict &&
            al.cpumode == PERF_RECORD_MISC_KERNEL) {
                if (!perf_evlist__exclude_kernel(top->session->evlist)) {
                        ui__warning(
"Kernel address maps (/proc/{kallsyms,modules}) are restricted.\n\n"
"Check /proc/sys/kernel/kptr_restrict.\n\n"
"Kernel%s samples will not be resolved.\n",
                          al.map && !RB_EMPTY_ROOT(&al.map->dso->symbols[MAP__FUNCTION]) ?
                          " modules" : "");
                        if (use_browser <= 0)
                                sleep(5);
                }
                machine->kptr_restrict_warned = true;
        }

        if (al.sym == NULL) {
                const char *msg = "Kernel samples will not be resolved.\n";
                /*
                 * As we do lazy loading of symtabs we only will know if the
                 * specified vmlinux file is invalid when we actually have a
                 * hit in kernel space and then try to load it. So if we get
                 * here and there are _no_ symbols in the DSO backing the
                 * kernel map, bail out.
                 *
                 * We may never get here, for instance, if we use -K/
                 * --hide-kernel-symbols, even if the user specifies an
                 * invalid --vmlinux ;-)
                 */
                if (!machine->kptr_restrict_warned && !top->vmlinux_warned &&
                    al.map == machine->vmlinux_maps[MAP__FUNCTION] &&
                    RB_EMPTY_ROOT(&al.map->dso->symbols[MAP__FUNCTION])) {
                        if (symbol_conf.vmlinux_name) {
                                char serr[256];
                                dso__strerror_load(al.map->dso, serr, sizeof(serr));
                                ui__warning("The %s file can't be used: %s\n%s",
                                            symbol_conf.vmlinux_name, serr, msg);
                        } else {
                                ui__warning("A vmlinux file was not found.\n%s",
                                            msg);
                        }

                        if (use_browser <= 0)
                                sleep(5);
                        top->vmlinux_warned = true;
                }
        }

        if (al.sym == NULL || !al.sym->idle) {
                struct hists *hists = evsel__hists(evsel);
                struct hist_entry_iter iter = {
                        .evsel          = evsel,
                        .sample         = sample,
                        .add_entry_cb   = hist_iter__top_callback,
                };

                if (symbol_conf.cumulate_callchain)
                        iter.ops = &hist_iter_cumulative;
                else
                        iter.ops = &hist_iter_normal;

                pthread_mutex_lock(&hists->lock);

                err = hist_entry_iter__add(&iter, &al, top->max_stack, top);
                if (err < 0)
                        pr_err("Problem incrementing symbol period, skipping event\n");

                pthread_mutex_unlock(&hists->lock);
        }

        addr_location__put(&al);
}

static void perf_top__mmap_read_idx(struct perf_top *top, int idx)
{
        struct record_opts *opts = &top->record_opts;
        struct perf_evlist *evlist = top->evlist;
        struct perf_sample sample;
        struct perf_evsel *evsel;
        struct perf_mmap *md;
        struct perf_session *session = top->session;
        union perf_event *event;
        struct machine *machine;
        u64 end, start;
        int ret;

        md = opts->overwrite ? &evlist->overwrite_mmap[idx] : &evlist->mmap[idx];
        if (perf_mmap__read_init(md, opts->overwrite, &start, &end) < 0)
                return;

        while ((event = perf_mmap__read_event(md, opts->overwrite, &start, end)) != NULL) {
                ret = perf_evlist__parse_sample(evlist, event, &sample);
                if (ret) {
                        pr_err("Can't parse sample, err = %d\n", ret);
                        goto next_event;
                }

                evsel = perf_evlist__id2evsel(session->evlist, sample.id);
                assert(evsel != NULL);

                if (event->header.type == PERF_RECORD_SAMPLE)
                        ++top->samples;

                switch (sample.cpumode) {
                case PERF_RECORD_MISC_USER:
                        ++top->us_samples;
                        if (top->hide_user_symbols)
                                goto next_event;
                        machine = &session->machines.host;
                        break;
                case PERF_RECORD_MISC_KERNEL:
                        ++top->kernel_samples;
                        if (top->hide_kernel_symbols)
                                goto next_event;
                        machine = &session->machines.host;
                        break;
                case PERF_RECORD_MISC_GUEST_KERNEL:
                        ++top->guest_kernel_samples;
                        machine = perf_session__find_machine(session,
                                                             sample.pid);
                        break;
                case PERF_RECORD_MISC_GUEST_USER:
                        ++top->guest_us_samples;
                        /*
                         * TODO: we don't process guest user from host side
                         * except simple counting.
                         */
                        goto next_event;
                default:
                        if (event->header.type == PERF_RECORD_SAMPLE)
                                goto next_event;
                        machine = &session->machines.host;
                        break;
                }


                if (event->header.type == PERF_RECORD_SAMPLE) {
                        perf_event__process_sample(&top->tool, event, evsel,
                                                   &sample, machine);
                } else if (event->header.type < PERF_RECORD_MAX) {
                        hists__inc_nr_events(evsel__hists(evsel), event->header.type);
                        machine__process_event(machine, event, &sample);
                } else
                        ++session->evlist->stats.nr_unknown_events;
next_event:
                perf_mmap__consume(md, opts->overwrite);
        }

        perf_mmap__read_done(md);
}

static void perf_top__mmap_read(struct perf_top *top)
{
        bool overwrite = top->record_opts.overwrite;
        struct perf_evlist *evlist = top->evlist;
        unsigned long long start, end;
        int i;

        start = rdclock();
        if (overwrite)
                perf_evlist__toggle_bkw_mmap(evlist, BKW_MMAP_DATA_PENDING);

        for (i = 0; i < top->evlist->nr_mmaps; i++)
                perf_top__mmap_read_idx(top, i);

        if (overwrite) {
                perf_evlist__toggle_bkw_mmap(evlist, BKW_MMAP_EMPTY);
                perf_evlist__toggle_bkw_mmap(evlist, BKW_MMAP_RUNNING);
        }
        end = rdclock();

        if ((end - start) > (unsigned long long)top->delay_secs * NSEC_PER_SEC)
                ui__warning("Too slow to read ring buffer.\n"
                            "Please try increasing the period (-c) or\n"
                            "decreasing the freq (-F) or\n"
                            "limiting the number of CPUs (-C)\n");
}

/*
 * Check per-event overwrite term.
 * perf top should support consistent term for all events.
 * - All events don't have per-event term
 *   E.g. "cpu/cpu-cycles/,cpu/instructions/"
 *   Nothing change, return 0.
 * - All events have same per-event term
 *   E.g. "cpu/cpu-cycles,no-overwrite/,cpu/instructions,no-overwrite/
 *   Using the per-event setting to replace the opts->overwrite if
 *   they are different, then return 0.
 * - Events have different per-event term
 *   E.g. "cpu/cpu-cycles,overwrite/,cpu/instructions,no-overwrite/"
 *   Return -1
 * - Some of the event set per-event term, but some not.
 *   E.g. "cpu/cpu-cycles/,cpu/instructions,no-overwrite/"
 *   Return -1
 */
static int perf_top__overwrite_check(struct perf_top *top)
{
        struct record_opts *opts = &top->record_opts;
        struct perf_evlist *evlist = top->evlist;
        struct perf_evsel_config_term *term;
        struct list_head *config_terms;
        struct perf_evsel *evsel;
        int set, overwrite = -1;

        evlist__for_each_entry(evlist, evsel) {
                set = -1;
                config_terms = &evsel->config_terms;
                list_for_each_entry(term, config_terms, list) {
                        if (term->type == PERF_EVSEL__CONFIG_TERM_OVERWRITE)
                                set = term->val.overwrite ? 1 : 0;
                }

                /* no term for current and previous event (likely) */
                if ((overwrite < 0) && (set < 0))
                        continue;

                /* has term for both current and previous event, compare */
                if ((overwrite >= 0) && (set >= 0) && (overwrite != set))
                        return -1;

                /* no term for current event but has term for previous one */
                if ((overwrite >= 0) && (set < 0))
                        return -1;

                /* has term for current event */
                if ((overwrite < 0) && (set >= 0)) {
                        /* if it's first event, set overwrite */
                        if (evsel == perf_evlist__first(evlist))
                                overwrite = set;
                        else
                                return -1;
                }
        }

        if ((overwrite >= 0) && (opts->overwrite != overwrite))
                opts->overwrite = overwrite;

        return 0;
}

static int perf_top_overwrite_fallback(struct perf_top *top,
                                       struct perf_evsel *evsel)
{
        struct record_opts *opts = &top->record_opts;
        struct perf_evlist *evlist = top->evlist;
        struct perf_evsel *counter;

        if (!opts->overwrite)
                return 0;

        /* only fall back when first event fails */
        if (evsel != perf_evlist__first(evlist))
                return 0;

        evlist__for_each_entry(evlist, counter)
                counter->attr.write_backward = false;
        opts->overwrite = false;
        ui__warning("fall back to non-overwrite mode\n");
        return 1;
}

static int perf_top__start_counters(struct perf_top *top)
{
        char msg[BUFSIZ];
        struct perf_evsel *counter;
        struct perf_evlist *evlist = top->evlist;
        struct record_opts *opts = &top->record_opts;

        if (perf_top__overwrite_check(top)) {
                ui__error("perf top only support consistent per-event "
                          "overwrite setting for all events\n");
                goto out_err;
        }

        perf_evlist__config(evlist, opts, &callchain_param);

        evlist__for_each_entry(evlist, counter) {
try_again:
                if (perf_evsel__open(counter, top->evlist->cpus,
                                     top->evlist->threads) < 0) {

                        /*
                         * Specially handle overwrite fall back.
                         * Because perf top is the only tool which has
                         * overwrite mode by default, support
                         * both overwrite and non-overwrite mode, and
                         * require consistent mode for all events.
                         *
                         * May move it to generic code with more tools
                         * have similar attribute.
                         */
                        if (perf_missing_features.write_backward &&
                            perf_top_overwrite_fallback(top, counter))
                                goto try_again;

                        if (perf_evsel__fallback(counter, errno, msg, sizeof(msg))) {
                                if (verbose > 0)
                                        ui__warning("%s\n", msg);
                                goto try_again;
                        }

                        perf_evsel__open_strerror(counter, &opts->target,
                                                  errno, msg, sizeof(msg));
                        ui__error("%s\n", msg);
                        goto out_err;
                }
        }

        if (perf_evlist__mmap(evlist, opts->mmap_pages) < 0) {
                ui__error("Failed to mmap with %d (%s)\n",
                            errno, str_error_r(errno, msg, sizeof(msg)));
                goto out_err;
        }

        return 0;

out_err:
        return -1;
}

static int callchain_param__setup_sample_type(struct callchain_param *callchain)
{
        if (!perf_hpp_list.sym) {
                if (callchain->enabled) {
                        ui__error("Selected -g but \"sym\" not present in --sort/-s.");
                        return -EINVAL;
                }
        } else if (callchain->mode != CHAIN_NONE) {
                if (callchain_register_param(callchain) < 0) {
                        ui__error("Can't register callchain params.\n");
                        return -EINVAL;
                }
        }

        return 0;
}

static int __cmd_top(struct perf_top *top)
{
        char msg[512];
        struct perf_evsel *pos;
        struct perf_evsel_config_term *err_term;
        struct perf_evlist *evlist = top->evlist;
        struct record_opts *opts = &top->record_opts;
        pthread_t thread;
        int ret;

        top->session = perf_session__new(NULL, false, NULL);
        if (top->session == NULL)
                return -1;

        if (!objdump_path) {
                ret = perf_env__lookup_objdump(&top->session->header.env);
                if (ret)
                        goto out_delete;
        }

        ret = callchain_param__setup_sample_type(&callchain_param);
        if (ret)
                goto out_delete;

        if (perf_session__register_idle_thread(top->session) < 0)
                goto out_delete;

        if (top->nr_threads_synthesize > 1)
                perf_set_multithreaded();

        machine__synthesize_threads(&top->session->machines.host, &opts->target,
                                    top->evlist->threads, false,
                                    opts->proc_map_timeout,
                                    top->nr_threads_synthesize);

        if (top->nr_threads_synthesize > 1)
                perf_set_singlethreaded();

        if (perf_hpp_list.socket) {
                ret = perf_env__read_cpu_topology_map(&perf_env);
                if (ret < 0)
                        goto out_err_cpu_topo;
        }

        ret = perf_top__start_counters(top);
        if (ret)
                goto out_delete;

        ret = perf_evlist__apply_drv_configs(evlist, &pos, &err_term);
        if (ret) {
                pr_err("failed to set config \"%s\" on event %s with %d (%s)\n",
                        err_term->val.drv_cfg, perf_evsel__name(pos), errno,
                        str_error_r(errno, msg, sizeof(msg)));
                goto out_delete;
        }

        top->session->evlist = top->evlist;
        perf_session__set_id_hdr_size(top->session);

        /*
         * When perf is starting the traced process, all the events (apart from
         * group members) have enable_on_exec=1 set, so don't spoil it by
         * prematurely enabling them.
         *
         * XXX 'top' still doesn't start workloads like record, trace, but should,
         * so leave the check here.
         */
        if (!target__none(&opts->target))
                perf_evlist__enable(top->evlist);

        /* Wait for a minimal set of events before starting the snapshot */
        perf_evlist__poll(top->evlist, 100);

        perf_top__mmap_read(top);

        ret = -1;
        if (pthread_create(&thread, NULL, (use_browser > 0 ? display_thread_tui :
                                                            display_thread), top)) {
                ui__error("Could not create display thread.\n");
                goto out_delete;
        }

        if (top->realtime_prio) {
                struct sched_param param;

                param.sched_priority = top->realtime_prio;
                if (sched_setscheduler(0, SCHED_FIFO, &param)) {
                        ui__error("Could not set realtime priority.\n");
                        goto out_join;
                }
        }

        while (!done) {
                u64 hits = top->samples;

                perf_top__mmap_read(top);

                if (opts->overwrite || (hits == top->samples))
                        ret = perf_evlist__poll(top->evlist, 100);

                if (resize) {
                        perf_top__resize(top);
                        resize = 0;
                }
        }

        ret = 0;
out_join:
        pthread_join(thread, NULL);
out_delete:
        perf_session__delete(top->session);
        top->session = NULL;

        return ret;

out_err_cpu_topo: {
        char errbuf[BUFSIZ];
        const char *err = str_error_r(-ret, errbuf, sizeof(errbuf));

        ui__error("Could not read the CPU topology map: %s\n", err);
        goto out_delete;
}
}

static int
callchain_opt(const struct option *opt, const char *arg, int unset)
{
        symbol_conf.use_callchain = true;
        return record_callchain_opt(opt, arg, unset);
}

static int
parse_callchain_opt(const struct option *opt, const char *arg, int unset)
{
        struct callchain_param *callchain = opt->value;

        callchain->enabled = !unset;
        callchain->record_mode = CALLCHAIN_FP;

        /*
         * --no-call-graph
         */
        if (unset) {
                symbol_conf.use_callchain = false;
                callchain->record_mode = CALLCHAIN_NONE;
                return 0;
        }

        return parse_callchain_top_opt(arg);
}

static int perf_top_config(const char *var, const char *value, void *cb __maybe_unused)
{
        if (!strcmp(var, "top.call-graph"))
                var = "call-graph.record-mode"; /* fall-through */
        if (!strcmp(var, "top.children")) {
                symbol_conf.cumulate_callchain = perf_config_bool(var, value);
                return 0;
        }

        return 0;
}

static int
parse_percent_limit(const struct option *opt, const char *arg,
                    int unset __maybe_unused)
{
        struct perf_top *top = opt->value;

        top->min_percent = strtof(arg, NULL);
        return 0;
}

const char top_callchain_help[] = CALLCHAIN_RECORD_HELP CALLCHAIN_REPORT_HELP
        "\n\t\t\t\tDefault: fp,graph,0.5,caller,function";

int cmd_top(int argc, const char **argv)
{
        char errbuf[BUFSIZ];
        struct perf_top top = {
                .count_filter        = 5,
                .delay_secs          = 2,
                .record_opts = {
                        .mmap_pages     = UINT_MAX,
                        .user_freq      = UINT_MAX,
                        .user_interval  = ULLONG_MAX,
                        .freq           = 4000, /* 4 KHz */
                        .target         = {
                                .uses_mmap   = true,
                        },
                        .proc_map_timeout    = 500,
                        .overwrite      = 1,
                },
                .max_stack           = sysctl_perf_event_max_stack,
                .sym_pcnt_filter     = 5,
                .nr_threads_synthesize = UINT_MAX,
        };
        struct record_opts *opts = &top.record_opts;
        struct target *target = &opts->target;
        const struct option options[] = {
        OPT_CALLBACK('e', "event", &top.evlist, "event",
                     "event selector. use 'perf list' to list available events",
                     parse_events_option),
        OPT_U64('c', "count", &opts->user_interval, "event period to sample"),
        OPT_STRING('p', "pid", &target->pid, "pid",
                    "profile events on existing process id"),
        OPT_STRING('t', "tid", &target->tid, "tid",
                    "profile events on existing thread id"),
        OPT_BOOLEAN('a', "all-cpus", &target->system_wide,
                            "system-wide collection from all CPUs"),
        OPT_STRING('C', "cpu", &target->cpu_list, "cpu",
                    "list of cpus to monitor"),
        OPT_STRING('k', "vmlinux", &symbol_conf.vmlinux_name,
                   "file", "vmlinux pathname"),
        OPT_BOOLEAN(0, "ignore-vmlinux", &symbol_conf.ignore_vmlinux,
                    "don't load vmlinux even if found"),
        OPT_BOOLEAN('K', "hide_kernel_symbols", &top.hide_kernel_symbols,
                    "hide kernel symbols"),
        OPT_CALLBACK('m', "mmap-pages", &opts->mmap_pages, "pages",
                     "number of mmap data pages",
                     perf_evlist__parse_mmap_pages),
        OPT_INTEGER('r', "realtime", &top.realtime_prio,
                    "collect data with this RT SCHED_FIFO priority"),
        OPT_INTEGER('d', "delay", &top.delay_secs,
                    "number of seconds to delay between refreshes"),
        OPT_BOOLEAN('D', "dump-symtab", &top.dump_symtab,
                            "dump the symbol table used for profiling"),
        OPT_INTEGER('f', "count-filter", &top.count_filter,
                    "only display functions with more events than this"),
        OPT_BOOLEAN(0, "group", &opts->group,
                            "put the counters into a counter group"),
        OPT_BOOLEAN('i', "no-inherit", &opts->no_inherit,
                    "child tasks do not inherit counters"),
        OPT_STRING(0, "sym-annotate", &top.sym_filter, "symbol name",
                    "symbol to annotate"),
        OPT_BOOLEAN('z', "zero", &top.zero, "zero history across updates"),
        OPT_UINTEGER('F', "freq", &opts->user_freq, "profile at this frequency"),
        OPT_INTEGER('E', "entries", &top.print_entries,
                    "display this many functions"),
        OPT_BOOLEAN('U', "hide_user_symbols", &top.hide_user_symbols,
                    "hide user symbols"),
        OPT_BOOLEAN(0, "tui", &top.use_tui, "Use the TUI interface"),
        OPT_BOOLEAN(0, "stdio", &top.use_stdio, "Use the stdio interface"),
        OPT_INCR('v', "verbose", &verbose,
                    "be more verbose (show counter open errors, etc)"),
        OPT_STRING('s', "sort", &sort_order, "key[,key2...]",
                   "sort by key(s): pid, comm, dso, symbol, parent, cpu, srcline, ..."
                   " Please refer the man page for the complete list."),
        OPT_STRING(0, "fields", &field_order, "key[,keys...]",
                   "output field(s): overhead, period, sample plus all of sort keys"),
        OPT_BOOLEAN('n', "show-nr-samples", &symbol_conf.show_nr_samples,
                    "Show a column with the number of samples"),
        OPT_CALLBACK_NOOPT('g', NULL, &callchain_param,
                           NULL, "enables call-graph recording and display",
                           &callchain_opt),
        OPT_CALLBACK(0, "call-graph", &callchain_param,
                     "record_mode[,record_size],print_type,threshold[,print_limit],order,sort_key[,branch]",
                     top_callchain_help, &parse_callchain_opt),
        OPT_BOOLEAN(0, "children", &symbol_conf.cumulate_callchain,
                    "Accumulate callchains of children and show total overhead as well"),
        OPT_INTEGER(0, "max-stack", &top.max_stack,
                    "Set the maximum stack depth when parsing the callchain. "
                    "Default: kernel.perf_event_max_stack or " __stringify(PERF_MAX_STACK_DEPTH)),
        OPT_CALLBACK(0, "ignore-callees", NULL, "regex",
                   "ignore callees of these functions in call graphs",
                   report_parse_ignore_callees_opt),
        OPT_BOOLEAN(0, "show-total-period", &symbol_conf.show_total_period,
                    "Show a column with the sum of periods"),
        OPT_STRING(0, "dsos", &symbol_conf.dso_list_str, "dso[,dso...]",
                   "only consider symbols in these dsos"),
        OPT_STRING(0, "comms", &symbol_conf.comm_list_str, "comm[,comm...]",
                   "only consider symbols in these comms"),
        OPT_STRING(0, "symbols", &symbol_conf.sym_list_str, "symbol[,symbol...]",
                   "only consider these symbols"),
        OPT_BOOLEAN(0, "source", &symbol_conf.annotate_src,
                    "Interleave source code with assembly code (default)"),
        OPT_BOOLEAN(0, "asm-raw", &symbol_conf.annotate_asm_raw,
                    "Display raw encoding of assembly instructions (default)"),
        OPT_BOOLEAN(0, "demangle-kernel", &symbol_conf.demangle_kernel,
                    "Enable kernel symbol demangling"),
        OPT_STRING(0, "objdump", &objdump_path, "path",
                    "objdump binary to use for disassembly and annotations"),
        OPT_STRING('M', "disassembler-style", &disassembler_style, "disassembler style",
                   "Specify disassembler style (e.g. -M intel for intel syntax)"),
        OPT_STRING('u', "uid", &target->uid_str, "user", "user to profile"),
        OPT_CALLBACK(0, "percent-limit", &top, "percent",
                     "Don't show entries under that percent", parse_percent_limit),
        OPT_CALLBACK(0, "percentage", NULL, "relative|absolute",
                     "How to display percentage of filtered entries", parse_filter_percentage),
        OPT_STRING('w', "column-widths", &symbol_conf.col_width_list_str,
                   "width[,width...]",
                   "don't try to adjust column width, use these fixed values"),
        OPT_UINTEGER(0, "proc-map-timeout", &opts->proc_map_timeout,
                        "per thread proc mmap processing timeout in ms"),
        OPT_CALLBACK_NOOPT('b', "branch-any", &opts->branch_stack,
                     "branch any", "sample any taken branches",
                     parse_branch_stack),
        OPT_CALLBACK('j', "branch-filter", &opts->branch_stack,
                     "branch filter mask", "branch stack filter modes",
                     parse_branch_stack),
        OPT_BOOLEAN(0, "raw-trace", &symbol_conf.raw_trace,
                    "Show raw trace event output (do not use print fmt or plugins)"),
        OPT_BOOLEAN(0, "hierarchy", &symbol_conf.report_hierarchy,
                    "Show entries in a hierarchy"),
        OPT_BOOLEAN(0, "force", &symbol_conf.force, "don't complain, do it"),
        OPT_UINTEGER(0, "num-thread-synthesize", &top.nr_threads_synthesize,
                        "number of thread to run event synthesize"),
        OPT_END()
        };
        const char * const top_usage[] = {
                "perf top [<options>]",
                NULL
        };
        int status = hists__init();

        if (status < 0)
                return status;

        top.evlist = perf_evlist__new();
        if (top.evlist == NULL)
                return -ENOMEM;

        status = perf_config(perf_top_config, &top);
        if (status)
                return status;

        argc = parse_options(argc, argv, options, top_usage, 0);
        if (argc)
                usage_with_options(top_usage, options);

        if (!top.evlist->nr_entries &&
            perf_evlist__add_default(top.evlist) < 0) {
                pr_err("Not enough memory for event selector list\n");
                goto out_delete_evlist;
        }

        if (symbol_conf.report_hierarchy) {
                /* disable incompatible options */
                symbol_conf.event_group = false;
                symbol_conf.cumulate_callchain = false;

                if (field_order) {
                        pr_err("Error: --hierarchy and --fields options cannot be used together\n");
                        parse_options_usage(top_usage, options, "fields", 0);
                        parse_options_usage(NULL, options, "hierarchy", 0);
                        goto out_delete_evlist;
                }
        }

        sort__mode = SORT_MODE__TOP;
        /* display thread wants entries to be collapsed in a different tree */
        perf_hpp_list.need_collapse = 1;

        if (top.use_stdio)
                use_browser = 0;
        else if (top.use_tui)
                use_browser = 1;

        setup_browser(false);

        if (setup_sorting(top.evlist) < 0) {
                if (sort_order)
                        parse_options_usage(top_usage, options, "s", 1);
                if (field_order)
                        parse_options_usage(sort_order ? NULL : top_usage,
                                            options, "fields", 0);
                goto out_delete_evlist;
        }

        status = target__validate(target);
        if (status) {
                target__strerror(target, status, errbuf, BUFSIZ);
                ui__warning("%s\n", errbuf);
        }

        status = target__parse_uid(target);
        if (status) {
                int saved_errno = errno;

                target__strerror(target, status, errbuf, BUFSIZ);
                ui__error("%s\n", errbuf);

                status = -saved_errno;
                goto out_delete_evlist;
        }

        if (target__none(target))
                target->system_wide = true;

        if (perf_evlist__create_maps(top.evlist, target) < 0) {
                ui__error("Couldn't create thread/CPU maps: %s\n",
                          errno == ENOENT ? "No such process" : str_error_r(errno, errbuf, sizeof(errbuf)));
                goto out_delete_evlist;
        }

        symbol_conf.nr_events = top.evlist->nr_entries;

        if (top.delay_secs < 1)
                top.delay_secs = 1;

        if (record_opts__config(opts)) {
                status = -EINVAL;
                goto out_delete_evlist;
        }

        top.sym_evsel = perf_evlist__first(top.evlist);

        if (!callchain_param.enabled) {
                symbol_conf.cumulate_callchain = false;
                perf_hpp__cancel_cumulate();
        }

        if (symbol_conf.cumulate_callchain && !callchain_param.order_set)
                callchain_param.order = ORDER_CALLER;

        status = symbol__annotation_init();
        if (status < 0)
                goto out_delete_evlist;

        symbol_conf.try_vmlinux_path = (symbol_conf.vmlinux_name == NULL);
        if (symbol__init(NULL) < 0)
                return -1;

        sort__setup_elide(stdout);

        get_term_dimensions(&top.winsize);
        if (top.print_entries == 0) {
                perf_top__update_print_entries(&top);
                signal(SIGWINCH, winch_sig);
        }

        status = __cmd_top(&top);

out_delete_evlist:
        perf_evlist__delete(top.evlist);

        return status;
}