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 };
  35
  36 static void *preload_thread(void *_data)
  37 {
  38         int nr, last_nr;
  39         struct thread_data *p = _data;
  40         struct index_state *index = p->index;
  41         struct cache_entry **cep = index->cache + p->offset;
  42         struct cache_def cache = CACHE_DEF_INIT;
  43
  44         nr = p->nr;
  45         if (nr + p->offset > index->cache_nr)
  46                 nr = index->cache_nr - p->offset;
  47         last_nr = nr;
  48
  49         do {
  50                 struct cache_entry *ce = *cep++;
  51                 struct stat st;
  52
  53                 if (ce_stage(ce))
  54                         continue;
  55                 if (S_ISGITLINK(ce->ce_mode))
  56                         continue;
  57                 if (ce_uptodate(ce))
  58                         continue;
  59                 if (ce_skip_worktree(ce))
  60                         continue;
  61                 if (ce->ce_flags & CE_FSMONITOR_VALID)
  62                         continue;
  63                 if (p->progress && !(nr & 31)) {
  64                         struct progress_data *pd = p->progress;
  65
  66                         pthread_mutex_lock(&pd->mutex);
  67                         pd->n += last_nr - nr;
  68                         display_progress(pd->progress, pd->n);
  69                         pthread_mutex_unlock(&pd->mutex);
  70                         last_nr = nr;
  71                 }
  72                 if (!ce_path_match(index, ce, &p->pathspec, NULL))
  73                         continue;
  74                 if (threaded_has_symlink_leading_path(&cache, ce->name, ce_namelen(ce)))
  75                         continue;
  76                 if (lstat(ce->name, &st))
  77                         continue;
  78                 if (ie_match_stat(index, ce, &st, CE_MATCH_RACY_IS_DIRTY|CE_MATCH_IGNORE_FSMONITOR))
  79                         continue;
  80                 ce_mark_uptodate(ce);
  81                 mark_fsmonitor_valid(index, ce);
  82         } while (--nr > 0);
  83         if (p->progress) {
  84                 struct progress_data *pd = p->progress;
  85
  86                 pthread_mutex_lock(&pd->mutex);
  87                 display_progress(pd->progress, pd->n + last_nr);
  88                 pthread_mutex_unlock(&pd->mutex);
  89         }
  90         cache_def_clear(&cache);
  91         return NULL;
  92 }
  93
  94 void preload_index(struct index_state *index,
  95                    const struct pathspec *pathspec,
  96                    unsigned int refresh_flags)
  97 {
  98         int threads, i, work, offset;
  99         struct thread_data data[MAX_PARALLEL];
 100         struct progress_data pd;
 101
 102         if (!HAVE_THREADS || !core_preload_index)
 103                 return;
 104
 105         threads = index->cache_nr / THREAD_COST;
 106         if ((index->cache_nr > 1) && (threads < 2) && git_env_bool("GIT_TEST_PRELOAD_INDEX", 0))
 107                 threads = 2;
 108         if (threads < 2)
 109                 return;
 110         trace_performance_enter();
 111         if (threads > MAX_PARALLEL)
 112                 threads = MAX_PARALLEL;
 113         offset = 0;
 114         work = DIV_ROUND_UP(index->cache_nr, threads);
 115         memset(&data, 0, sizeof(data));
 116
 117         memset(&pd, 0, sizeof(pd));
 118         if (refresh_flags & REFRESH_PROGRESS && isatty(2)) {
 119                 pd.progress = start_delayed_progress(_("Refreshing index"), index->cache_nr);
 120                 pthread_mutex_init(&pd.mutex, NULL);
 121         }
 122
 123         for (i = 0; i < threads; i++) {
 124                 struct thread_data *p = data+i;
 125                 int err;
 126
 127                 p->index = index;
 128                 if (pathspec)
 129                         copy_pathspec(&p->pathspec, pathspec);
 130                 p->offset = offset;
 131                 p->nr = work;
 132                 if (pd.progress)
 133                         p->progress = &pd;
 134                 offset += work;
 135                 err = pthread_create(&p->pthread, NULL, preload_thread, p);
 136
 137                 if (err)
 138                         die(_("unable to create threaded lstat: %s"), strerror(err));
 139         }
 140         for (i = 0; i < threads; i++) {
 141                 struct thread_data *p = data+i;
 142                 if (pthread_join(p->pthread, NULL))
 143                         die("unable to join threaded lstat");
 144         }
 145         stop_progress(&pd.progress);
 146
 147         trace_performance_leave("preload index");
 148 }
 149
 150 int repo_read_index_preload(struct repository *repo,
 151                             const struct pathspec *pathspec,
 152                             unsigned int refresh_flags)
 153 {
 154         int retval = repo_read_index(repo);
 155
 156         preload_index(repo->index, pathspec, refresh_flags);
 157         return retval;
 158 }