preload-index.c

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