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
  11 #ifdef NO_PTHREADS
  12 static void preload_index(struct index_state *index,
  13                           const struct pathspec *pathspec,
  14                           unsigned int refresh_flags)
  15 {
  16         ; /* nothing */
  17 }
  18 #else
  19
  20 #include <pthread.h>
  21
  22 /*
  23  * Mostly randomly chosen maximum thread counts: we
  24  * cap the parallelism to 20 threads, and we want
  25  * to have at least 500 lstat's per thread for it to
  26  * be worth starting a thread.
  27  */
  28 #define MAX_PARALLEL (20)
  29 #define THREAD_COST (500)
  30
  31 struct progress_data {
  32         unsigned long n;
  33         struct progress *progress;
  34         pthread_mutex_t mutex;
  35 };
  36
  37 struct thread_data {
  38         pthread_t pthread;
  39         struct index_state *index;
  40         struct pathspec pathspec;
  41         struct progress_data *progress;
  42         int offset, nr;
  43 };
  44
  45 static void *preload_thread(void *_data)
  46 {
  47         int nr, last_nr;
  48         struct thread_data *p = _data;
  49         struct index_state *index = p->index;
  50         struct cache_entry **cep = index->cache + p->offset;
  51         struct cache_def cache = CACHE_DEF_INIT;
  52
  53         nr = p->nr;
  54         if (nr + p->offset > index->cache_nr)
  55                 nr = index->cache_nr - p->offset;
  56         last_nr = nr;
  57
  58         do {
  59                 struct cache_entry *ce = *cep++;
  60                 struct stat st;
  61
  62                 if (ce_stage(ce))
  63                         continue;
  64                 if (S_ISGITLINK(ce->ce_mode))
  65                         continue;
  66                 if (ce_uptodate(ce))
  67                         continue;
  68                 if (ce_skip_worktree(ce))
  69                         continue;
  70                 if (ce->ce_flags & CE_FSMONITOR_VALID)
  71                         continue;
  72                 if (p->progress && !(nr & 31)) {
  73                         struct progress_data *pd = p->progress;
  74
  75                         pthread_mutex_lock(&pd->mutex);
  76                         pd->n += last_nr - nr;
  77                         display_progress(pd->progress, pd->n);
  78                         pthread_mutex_unlock(&pd->mutex);
  79                         last_nr = nr;
  80                 }
  81                 if (!ce_path_match(index, ce, &p->pathspec, NULL))
  82                         continue;
  83                 if (threaded_has_symlink_leading_path(&cache, ce->name, ce_namelen(ce)))
  84                         continue;
  85                 if (lstat(ce->name, &st))
  86                         continue;
  87                 if (ie_match_stat(index, ce, &st, CE_MATCH_RACY_IS_DIRTY|CE_MATCH_IGNORE_FSMONITOR))
  88                         continue;
  89                 ce_mark_uptodate(ce);
  90                 mark_fsmonitor_valid(ce);
  91         } while (--nr > 0);
  92         if (p->progress) {
  93                 struct progress_data *pd = p->progress;
  94
  95                 pthread_mutex_lock(&pd->mutex);
  96                 display_progress(pd->progress, pd->n + last_nr);
  97                 pthread_mutex_unlock(&pd->mutex);
  98         }
  99         cache_def_clear(&cache);
 100         return NULL;
 101 }
 102
 103 static void preload_index(struct index_state *index,
 104                           const struct pathspec *pathspec,
 105                           unsigned int refresh_flags)
 106 {
 107         int threads, i, work, offset;
 108         struct thread_data data[MAX_PARALLEL];
 109         struct progress_data pd;
 110
 111         if (!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         trace_performance_enter();
 120         if (threads > MAX_PARALLEL)
 121                 threads = MAX_PARALLEL;
 122         offset = 0;
 123         work = DIV_ROUND_UP(index->cache_nr, threads);
 124         memset(&data, 0, sizeof(data));
 125
 126         memset(&pd, 0, sizeof(pd));
 127         if (refresh_flags & REFRESH_PROGRESS && isatty(2)) {
 128                 pd.progress = start_delayed_progress(_("Refreshing index"), index->cache_nr);
 129                 pthread_mutex_init(&pd.mutex, NULL);
 130         }
 131
 132         for (i = 0; i < threads; i++) {
 133                 struct thread_data *p = data+i;
 134                 p->index = index;
 135                 if (pathspec)
 136                         copy_pathspec(&p->pathspec, pathspec);
 137                 p->offset = offset;
 138                 p->nr = work;
 139                 if (pd.progress)
 140                         p->progress = &pd;
 141                 offset += work;
 142                 if (pthread_create(&p->pthread, NULL, preload_thread, p))
 143                         die("unable to create threaded lstat");
 144         }
 145         for (i = 0; i < threads; i++) {
 146                 struct thread_data *p = data+i;
 147                 if (pthread_join(p->pthread, NULL))
 148                         die("unable to join threaded lstat");
 149         }
 150         stop_progress(&pd.progress);
 151
 152         trace_performance_leave("preload index");
 153 }
 154 #endif
 155
 156 int read_index_preload(struct index_state *index,
 157                        const struct pathspec *pathspec,
 158                        unsigned int refresh_flags)
 159 {
 160         int retval = read_index(index);
 161
 162         preload_index(index, pathspec, refresh_flags);
 163         return retval;
 164 }