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