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