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