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