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