preload-index.c

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