t5800: point out that deleting branches does not work
[git/dscho.git] / preload-index.c
blob49cb08df96faa90101bb25d8f96acaffc066f19b
1 /*
2  * Copyright (C) 2008 Linus Torvalds
3  */
4 #include "cache.h"
6 #ifdef NO_PTHREADS
7 static void preload_index(struct index_state *index, const char **pathspec)
9         ; /* nothing */
11 #else
13 #include <pthread.h>
16  * Mostly randomly chosen maximum thread counts: we
17  * cap the parallelism to 20 threads, and we want
18  * to have at least 500 lstat's per thread for it to
19  * be worth starting a thread.
20  */
21 #define MAX_PARALLEL (20)
22 #define THREAD_COST (500)
24 struct thread_data {
25         pthread_t pthread;
26         struct index_state *index;
27         const char **pathspec;
28         int offset, nr;
31 static void *preload_thread(void *_data)
33         int nr;
34         struct thread_data *p = _data;
35         struct index_state *index = p->index;
36         struct cache_entry **cep = index->cache + p->offset;
37         struct cache_def cache;
38         struct pathspec pathspec;
40         init_pathspec(&pathspec, p->pathspec);
41         memset(&cache, 0, sizeof(cache));
42         nr = p->nr;
43         if (nr + p->offset > index->cache_nr)
44                 nr = index->cache_nr - p->offset;
46         do {
47                 struct cache_entry *ce = *cep++;
48                 struct stat st;
50                 if (ce_stage(ce))
51                         continue;
52                 if (S_ISGITLINK(ce->ce_mode))
53                         continue;
54                 if (ce_uptodate(ce))
55                         continue;
56                 if (!ce_path_match(ce, &pathspec))
57                         continue;
58                 if (threaded_has_symlink_leading_path(&cache, ce->name, ce_namelen(ce)))
59                         continue;
60                 if (lstat(ce->name, &st))
61                         continue;
62                 if (ie_match_stat(index, ce, &st, CE_MATCH_RACY_IS_DIRTY))
63                         continue;
64                 ce_mark_uptodate(ce);
65         } while (--nr > 0);
66         free_pathspec(&pathspec);
67         return NULL;
70 static void preload_index(struct index_state *index, const char **pathspec)
72         int threads, i, work, offset;
73         struct thread_data data[MAX_PARALLEL];
75         if (!core_preload_index)
76                 return;
78         threads = index->cache_nr / THREAD_COST;
79         if (threads < 2)
80                 return;
81         if (threads > MAX_PARALLEL)
82                 threads = MAX_PARALLEL;
83         offset = 0;
84         work = DIV_ROUND_UP(index->cache_nr, threads);
85         for (i = 0; i < threads; i++) {
86                 struct thread_data *p = data+i;
87                 p->index = index;
88                 p->pathspec = pathspec;
89                 p->offset = offset;
90                 p->nr = work;
91                 offset += work;
92                 if (pthread_create(&p->pthread, NULL, preload_thread, p))
93                         die("unable to create threaded lstat");
94         }
95         for (i = 0; i < threads; i++) {
96                 struct thread_data *p = data+i;
97                 if (pthread_join(p->pthread, NULL))
98                         die("unable to join threaded lstat");
99         }
101 #endif
103 int read_index_preload(struct index_state *index, const char **pathspec)
105         int retval = read_index(index);
107         preload_index(index, pathspec);
108         return retval;