preload-index.c

   1 /*
   2  * Copyright (C) 2008 Linus Torvalds
   3  */
   4
   5 #define USE_THE_REPOSITORY_VARIABLE
   6
   7 #include "git-compat-util.h"
   8 #include "pathspec.h"
   9 #include "dir.h"
  10 #include "environment.h"
  11 #include "fsmonitor.h"
  12 #include "gettext.h"
  13 #include "parse.h"
  14 #include "preload-index.h"
  15 #include "progress.h"
  16 #include "read-cache.h"
  17 #include "thread-utils.h"
  18 #include "repository.h"
  19 #include "symlinks.h"
  20 #include "trace2.h"
  21
  22 /*
  23  * Mostly randomly chosen maximum thread counts: we
  24  * cap the parallelism to 20 threads, and we want
  25  * to have at least 500 lstat's per thread for it to
  26  * be worth starting a thread.
  27  */
  28 #define MAX_PARALLEL (20)
  29 #define THREAD_COST (500)
  30
  31 struct progress_data {
  32         unsigned long n;
  33         struct progress *progress;
  34         pthread_mutex_t mutex;
  35 };
  36
  37 struct thread_data {
  38         pthread_t pthread;
  39         struct index_state *index;
  40         struct pathspec pathspec;
  41         struct progress_data *progress;
  42         int offset, nr;
  43         int t2_nr_lstat;
  44 };
  45
  46 static void *preload_thread(void *_data)
  47 {
  48         int nr, last_nr;
  49         struct thread_data *p = _data;
  50         struct index_state *index = p->index;
  51         struct cache_entry **cep = index->cache + p->offset;
  52         struct cache_def cache = CACHE_DEF_INIT;
  53
  54         nr = p->nr;
  55         if (nr + p->offset > index->cache_nr)
  56                 nr = index->cache_nr - p->offset;
  57         last_nr = nr;
  58
  59         do {
  60                 struct cache_entry *ce = *cep++;
  61                 struct stat st;
  62
  63                 if (ce_stage(ce))
  64                         continue;
  65                 if (S_ISGITLINK(ce->ce_mode))
  66                         continue;
  67                 if (ce_uptodate(ce))
  68                         continue;
  69                 if (ce_skip_worktree(ce))
  70                         continue;
  71                 if (ce->ce_flags & CE_FSMONITOR_VALID)
  72                         continue;
  73                 if (p->progress && !(nr & 31)) {
  74                         struct progress_data *pd = p->progress;
  75
  76                         pthread_mutex_lock(&pd->mutex);
  77                         pd->n += last_nr - nr;
  78                         display_progress(pd->progress, pd->n);
  79                         pthread_mutex_unlock(&pd->mutex);
  80                         last_nr = nr;
  81                 }
  82                 if (!ce_path_match(index, ce, &p->pathspec, NULL))
  83                         continue;
  84                 if (threaded_has_symlink_leading_path(&cache, ce->name, ce_namelen(ce)))
  85                         continue;
  86                 p->t2_nr_lstat++;
  87                 if (lstat(ce->name, &st))
  88                         continue;
  89                 if (ie_match_stat(index, ce, &st, CE_MATCH_RACY_IS_DIRTY|CE_MATCH_IGNORE_FSMONITOR))
  90                         continue;
  91                 ce_mark_uptodate(ce);
  92                 mark_fsmonitor_valid(index, ce);
  93         } while (--nr > 0);
  94         if (p->progress) {
  95                 struct progress_data *pd = p->progress;
  96
  97                 pthread_mutex_lock(&pd->mutex);
  98                 display_progress(pd->progress, pd->n + last_nr);
  99                 pthread_mutex_unlock(&pd->mutex);
 100         }
 101         cache_def_clear(&cache);
 102         return NULL;
 103 }
 104
 105 void preload_index(struct index_state *index,
 106                    const struct pathspec *pathspec,
 107                    unsigned int refresh_flags)
 108 {
 109         int threads, i, work, offset;
 110         struct thread_data data[MAX_PARALLEL];
 111         struct progress_data pd;
 112         int t2_sum_lstat = 0;
 113
 114         if (!HAVE_THREADS || !core_preload_index)
 115                 return;
 116
 117         threads = index->cache_nr / THREAD_COST;
 118         if ((index->cache_nr > 1) && (threads < 2) && git_env_bool("GIT_TEST_PRELOAD_INDEX", 0))
 119                 threads = 2;
 120         if (threads < 2)
 121                 return;
 122
 123         trace2_region_enter("index", "preload", NULL);
 124
 125         trace_performance_enter();
 126         if (threads > MAX_PARALLEL)
 127                 threads = MAX_PARALLEL;
 128         offset = 0;
 129         work = DIV_ROUND_UP(index->cache_nr, threads);
 130         memset(&data, 0, sizeof(data));
 131
 132         memset(&pd, 0, sizeof(pd));
 133         if (refresh_flags & REFRESH_PROGRESS && isatty(2)) {
 134                 pd.progress = start_delayed_progress(_("Refreshing index"), index->cache_nr);
 135                 pthread_mutex_init(&pd.mutex, NULL);
 136         }
 137
 138         for (i = 0; i < threads; i++) {
 139                 struct thread_data *p = data+i;
 140                 int err;
 141
 142                 p->index = index;
 143                 if (pathspec)
 144                         copy_pathspec(&p->pathspec, pathspec);
 145                 p->offset = offset;
 146                 p->nr = work;
 147                 if (pd.progress)
 148                         p->progress = &pd;
 149                 offset += work;
 150                 err = pthread_create(&p->pthread, NULL, preload_thread, p);
 151
 152                 if (err)
 153                         die(_("unable to create threaded lstat: %s"), strerror(err));
 154         }
 155         for (i = 0; i < threads; i++) {
 156                 struct thread_data *p = data+i;
 157                 if (pthread_join(p->pthread, NULL))
 158                         die("unable to join threaded lstat");
 159                 t2_sum_lstat += p->t2_nr_lstat;
 160         }
 161         stop_progress(&pd.progress);
 162
 163         if (pathspec) {
 164                 /* earlier we made deep copies for each thread to work with */
 165                 for (i = 0; i < threads; i++)
 166                         clear_pathspec(&data[i].pathspec);
 167         }
 168
 169         trace_performance_leave("preload index");
 170
 171         trace2_data_intmax("index", NULL, "preload/sum_lstat", t2_sum_lstat);
 172         trace2_region_leave("index", "preload", NULL);
 173 }
 174
 175 int repo_read_index_preload(struct repository *repo,
 176                             const struct pathspec *pathspec,
 177                             unsigned int refresh_flags)
 178 {
 179         int retval = repo_read_index(repo);
 180
 181         preload_index(repo->index, pathspec, refresh_flags);
 182         return retval;
 183 }