arch/powerpc/kvm/timing.c

   1 /*
   2  * This program is free software; you can redistribute it and/or modify
   3  * it under the terms of the GNU General Public License, version 2, as
   4  * published by the Free Software Foundation.
   5  *
   6  * This program is distributed in the hope that it will be useful,
   7  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   8  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   9  * GNU General Public License for more details.
  10  *
  11  * You should have received a copy of the GNU General Public License
  12  * along with this program; if not, write to the Free Software
  13  * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  14  *
  15  * Copyright IBM Corp. 2008
  16  *
  17  * Authors: Hollis Blanchard <hollisb@us.ibm.com>
  18  *          Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
  19  */
  20
  21 #include <linux/kvm_host.h>
  22 #include <linux/fs.h>
  23 #include <linux/seq_file.h>
  24 #include <linux/debugfs.h>
  25 #include <linux/uaccess.h>
  26 #include <linux/module.h>
  27
  28 #include <asm/time.h>
  29 #include <asm-generic/div64.h>
  30
  31 #include "timing.h"
  32
  33 void kvmppc_init_timing_stats(struct kvm_vcpu *vcpu)
  34 {
  35         int i;
  36
  37         /* Take a lock to avoid concurrent updates */
  38         mutex_lock(&vcpu->arch.exit_timing_lock);
  39
  40         vcpu->arch.last_exit_type = 0xDEAD;
  41         for (i = 0; i < __NUMBER_OF_KVM_EXIT_TYPES; i++) {
  42                 vcpu->arch.timing_count_type[i] = 0;
  43                 vcpu->arch.timing_max_duration[i] = 0;
  44                 vcpu->arch.timing_min_duration[i] = 0xFFFFFFFF;
  45                 vcpu->arch.timing_sum_duration[i] = 0;
  46                 vcpu->arch.timing_sum_quad_duration[i] = 0;
  47         }
  48         vcpu->arch.timing_last_exit = 0;
  49         vcpu->arch.timing_exit.tv64 = 0;
  50         vcpu->arch.timing_last_enter.tv64 = 0;
  51
  52         mutex_unlock(&vcpu->arch.exit_timing_lock);
  53 }
  54
  55 static void add_exit_timing(struct kvm_vcpu *vcpu, u64 duration, int type)
  56 {
  57         u64 old;
  58
  59         mutex_lock(&vcpu->arch.exit_timing_lock);
  60
  61         vcpu->arch.timing_count_type[type]++;
  62
  63         /* sum */
  64         old = vcpu->arch.timing_sum_duration[type];
  65         vcpu->arch.timing_sum_duration[type] += duration;
  66         if (unlikely(old > vcpu->arch.timing_sum_duration[type])) {
  67                 printk(KERN_ERR"%s - wrap adding sum of durations"
  68                         " old %lld new %lld type %d exit # of type %d\n",
  69                         __func__, old, vcpu->arch.timing_sum_duration[type],
  70                         type, vcpu->arch.timing_count_type[type]);
  71         }
  72
  73         /* square sum */
  74         old = vcpu->arch.timing_sum_quad_duration[type];
  75         vcpu->arch.timing_sum_quad_duration[type] += (duration*duration);
  76         if (unlikely(old > vcpu->arch.timing_sum_quad_duration[type])) {
  77                 printk(KERN_ERR"%s - wrap adding sum of squared durations"
  78                         " old %lld new %lld type %d exit # of type %d\n",
  79                         __func__, old,
  80                         vcpu->arch.timing_sum_quad_duration[type],
  81                         type, vcpu->arch.timing_count_type[type]);
  82         }
  83
  84         /* set min/max */
  85         if (unlikely(duration < vcpu->arch.timing_min_duration[type]))
  86                 vcpu->arch.timing_min_duration[type] = duration;
  87         if (unlikely(duration > vcpu->arch.timing_max_duration[type]))
  88                 vcpu->arch.timing_max_duration[type] = duration;
  89
  90         mutex_unlock(&vcpu->arch.exit_timing_lock);
  91 }
  92
  93 void kvmppc_update_timing_stats(struct kvm_vcpu *vcpu)
  94 {
  95         u64 exit = vcpu->arch.timing_last_exit;
  96         u64 enter = vcpu->arch.timing_last_enter.tv64;
  97
  98         /* save exit time, used next exit when the reenter time is known */
  99         vcpu->arch.timing_last_exit = vcpu->arch.timing_exit.tv64;
 100
 101         if (unlikely(vcpu->arch.last_exit_type == 0xDEAD || exit == 0))
 102                 return; /* skip incomplete cycle (e.g. after reset) */
 103
 104         /* update statistics for average and standard deviation */
 105         add_exit_timing(vcpu, (enter - exit), vcpu->arch.last_exit_type);
 106         /* enter -> timing_last_exit is time spent in guest - log this too */
 107         add_exit_timing(vcpu, (vcpu->arch.timing_last_exit - enter),
 108                         TIMEINGUEST);
 109 }
 110
 111 static const char *kvm_exit_names[__NUMBER_OF_KVM_EXIT_TYPES] = {
 112         [MMIO_EXITS] =              "MMIO",
 113         [SIGNAL_EXITS] =            "SIGNAL",
 114         [ITLB_REAL_MISS_EXITS] =    "ITLBREAL",
 115         [ITLB_VIRT_MISS_EXITS] =    "ITLBVIRT",
 116         [DTLB_REAL_MISS_EXITS] =    "DTLBREAL",
 117         [DTLB_VIRT_MISS_EXITS] =    "DTLBVIRT",
 118         [SYSCALL_EXITS] =           "SYSCALL",
 119         [ISI_EXITS] =               "ISI",
 120         [DSI_EXITS] =               "DSI",
 121         [EMULATED_INST_EXITS] =     "EMULINST",
 122         [EMULATED_MTMSRWE_EXITS] =  "EMUL_WAIT",
 123         [EMULATED_WRTEE_EXITS] =    "EMUL_WRTEE",
 124         [EMULATED_MTSPR_EXITS] =    "EMUL_MTSPR",
 125         [EMULATED_MFSPR_EXITS] =    "EMUL_MFSPR",
 126         [EMULATED_MTMSR_EXITS] =    "EMUL_MTMSR",
 127         [EMULATED_MFMSR_EXITS] =    "EMUL_MFMSR",
 128         [EMULATED_TLBSX_EXITS] =    "EMUL_TLBSX",
 129         [EMULATED_TLBWE_EXITS] =    "EMUL_TLBWE",
 130         [EMULATED_RFI_EXITS] =      "EMUL_RFI",
 131         [DEC_EXITS] =               "DEC",
 132         [EXT_INTR_EXITS] =          "EXTINT",
 133         [HALT_WAKEUP] =             "HALT",
 134         [USR_PR_INST] =             "USR_PR_INST",
 135         [FP_UNAVAIL] =              "FP_UNAVAIL",
 136         [DEBUG_EXITS] =             "DEBUG",
 137         [TIMEINGUEST] =             "TIMEINGUEST"
 138 };
 139
 140 static int kvmppc_exit_timing_show(struct seq_file *m, void *private)
 141 {
 142         struct kvm_vcpu *vcpu = m->private;
 143         int i;
 144         u64 min, max, sum, sum_quad;
 145
 146         seq_puts(m, "type       count   min     max     sum     sum_squared\n");
 147
 148         for (i = 0; i < __NUMBER_OF_KVM_EXIT_TYPES; i++) {
 149
 150                 min = vcpu->arch.timing_min_duration[i];
 151                 do_div(min, tb_ticks_per_usec);
 152                 max = vcpu->arch.timing_max_duration[i];
 153                 do_div(max, tb_ticks_per_usec);
 154                 sum = vcpu->arch.timing_sum_duration[i];
 155                 do_div(sum, tb_ticks_per_usec);
 156                 sum_quad = vcpu->arch.timing_sum_quad_duration[i];
 157                 do_div(sum_quad, tb_ticks_per_usec);
 158
 159                 seq_printf(m, "%12s     %10d    %10lld  %10lld  %20lld  %20lld\n",
 160                         kvm_exit_names[i],
 161                         vcpu->arch.timing_count_type[i],
 162                         min,
 163                         max,
 164                         sum,
 165                         sum_quad);
 166
 167         }
 168         return 0;
 169 }
 170
 171 /* Write 'c' to clear the timing statistics. */
 172 static ssize_t kvmppc_exit_timing_write(struct file *file,
 173                                        const char __user *user_buf,
 174                                        size_t count, loff_t *ppos)
 175 {
 176         int err = -EINVAL;
 177         char c;
 178
 179         if (count > 1) {
 180                 goto done;
 181         }
 182
 183         if (get_user(c, user_buf)) {
 184                 err = -EFAULT;
 185                 goto done;
 186         }
 187
 188         if (c == 'c') {
 189                 struct seq_file *seqf = file->private_data;
 190                 struct kvm_vcpu *vcpu = seqf->private;
 191                 /* Write does not affect our buffers previously generated with
 192                  * show. seq_file is locked here to prevent races of init with
 193                  * a show call */
 194                 mutex_lock(&seqf->lock);
 195                 kvmppc_init_timing_stats(vcpu);
 196                 mutex_unlock(&seqf->lock);
 197                 err = count;
 198         }
 199
 200 done:
 201         return err;
 202 }
 203
 204 static int kvmppc_exit_timing_open(struct inode *inode, struct file *file)
 205 {
 206         return single_open(file, kvmppc_exit_timing_show, inode->i_private);
 207 }
 208
 209 static const struct file_operations kvmppc_exit_timing_fops = {
 210         .owner   = THIS_MODULE,
 211         .open    = kvmppc_exit_timing_open,
 212         .read    = seq_read,
 213         .write   = kvmppc_exit_timing_write,
 214         .llseek  = seq_lseek,
 215         .release = single_release,
 216 };
 217
 218 void kvmppc_create_vcpu_debugfs(struct kvm_vcpu *vcpu, unsigned int id)
 219 {
 220         static char dbg_fname[50];
 221         struct dentry *debugfs_file;
 222
 223         snprintf(dbg_fname, sizeof(dbg_fname), "vm%u_vcpu%u_timing",
 224                  current->pid, id);
 225         debugfs_file = debugfs_create_file(dbg_fname, 0666,
 226                                         kvm_debugfs_dir, vcpu,
 227                                         &kvmppc_exit_timing_fops);
 228
 229         if (!debugfs_file) {
 230                 printk(KERN_ERR"%s: error creating debugfs file %s\n",
 231                         __func__, dbg_fname);
 232                 return;
 233         }
 234
 235         vcpu->arch.debugfs_exit_timing = debugfs_file;
 236 }
 237
 238 void kvmppc_remove_vcpu_debugfs(struct kvm_vcpu *vcpu)
 239 {
 240         if (vcpu->arch.debugfs_exit_timing) {
 241                 debugfs_remove(vcpu->arch.debugfs_exit_timing);
 242                 vcpu->arch.debugfs_exit_timing = NULL;
 243         }
 244 }