git

1
/*
2
 * Copyright (C) 2008 Linus Torvalds
3
 */
4
#include "git-compat-util.h"
5
#include "pathspec.h"
6
#include "dir.h"
7
#include "environment.h"
8
#include "fsmonitor.h"
9
#include "gettext.h"
10
#include "parse.h"
11
#include "preload-index.h"
12
#include "progress.h"
13
#include "read-cache.h"
14
#include "thread-utils.h"
15
#include "repository.h"
16
#include "symlinks.h"
17
#include "trace2.h"
18

19
/*
20
 * Mostly randomly chosen maximum thread counts: we
21
 * cap the parallelism to 20 threads, and we want
22
 * to have at least 500 lstat's per thread for it to
23
 * be worth starting a thread.
24
 */
25
#define MAX_PARALLEL (20)
26
#define THREAD_COST (500)
27

28
struct progress_data {
29
	unsigned long n;
30
	struct progress *progress;
31
	pthread_mutex_t mutex;
32
};
33

34
struct thread_data {
35
	pthread_t pthread;
36
	struct index_state *index;
37
	struct pathspec pathspec;
38
	struct progress_data *progress;
39
	int offset, nr;
40
	int t2_nr_lstat;
41
};
42

43
static void *preload_thread(void *_data)
44
{
45
	int nr, last_nr;
46
	struct thread_data *p = _data;
47
	struct index_state *index = p->index;
48
	struct cache_entry **cep = index->cache + p->offset;
49
	struct cache_def cache = CACHE_DEF_INIT;
50

51
	nr = p->nr;
52
	if (nr + p->offset > index->cache_nr)
53
		nr = index->cache_nr - p->offset;
54
	last_nr = nr;
55

56
	do {
57
		struct cache_entry *ce = *cep++;
58
		struct stat st;
59

60
		if (ce_stage(ce))
61
			continue;
62
		if (S_ISGITLINK(ce->ce_mode))
63
			continue;
64
		if (ce_uptodate(ce))
65
			continue;
66
		if (ce_skip_worktree(ce))
67
			continue;
68
		if (ce->ce_flags & CE_FSMONITOR_VALID)
69
			continue;
70
		if (p->progress && !(nr & 31)) {
71
			struct progress_data *pd = p->progress;
72

73
			pthread_mutex_lock(&pd->mutex);
74
			pd->n += last_nr - nr;
75
			display_progress(pd->progress, pd->n);
76
			pthread_mutex_unlock(&pd->mutex);
77
			last_nr = nr;
78
		}
79
		if (!ce_path_match(index, ce, &p->pathspec, NULL))
80
			continue;
81
		if (threaded_has_symlink_leading_path(&cache, ce->name, ce_namelen(ce)))
82
			continue;
83
		p->t2_nr_lstat++;
84
		if (lstat(ce->name, &st))
85
			continue;
86
		if (ie_match_stat(index, ce, &st, CE_MATCH_RACY_IS_DIRTY|CE_MATCH_IGNORE_FSMONITOR))
87
			continue;
88
		ce_mark_uptodate(ce);
89
		mark_fsmonitor_valid(index, ce);
90
	} while (--nr > 0);
91
	if (p->progress) {
92
		struct progress_data *pd = p->progress;
93

94
		pthread_mutex_lock(&pd->mutex);
95
		display_progress(pd->progress, pd->n + last_nr);
96
		pthread_mutex_unlock(&pd->mutex);
97
	}
98
	cache_def_clear(&cache);
99
	return NULL;
100
}
101

102
void preload_index(struct index_state *index,
103
		   const struct pathspec *pathspec,
104
		   unsigned int refresh_flags)
105
{
106
	int threads, i, work, offset;
107
	struct thread_data data[MAX_PARALLEL];
108
	struct progress_data pd;
109
	int t2_sum_lstat = 0;
110

111
	if (!HAVE_THREADS || !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

120
	trace2_region_enter("index", "preload", NULL);
121

122
	trace_performance_enter();
123
	if (threads > MAX_PARALLEL)
124
		threads = MAX_PARALLEL;
125
	offset = 0;
126
	work = DIV_ROUND_UP(index->cache_nr, threads);
127
	memset(&data, 0, sizeof(data));
128

129
	memset(&pd, 0, sizeof(pd));
130
	if (refresh_flags & REFRESH_PROGRESS && isatty(2)) {
131
		pd.progress = start_delayed_progress(_("Refreshing index"), index->cache_nr);
132
		pthread_mutex_init(&pd.mutex, NULL);
133
	}
134

135
	for (i = 0; i < threads; i++) {
136
		struct thread_data *p = data+i;
137
		int err;
138

139
		p->index = index;
140
		if (pathspec)
141
			copy_pathspec(&p->pathspec, pathspec);
142
		p->offset = offset;
143
		p->nr = work;
144
		if (pd.progress)
145
			p->progress = &pd;
146
		offset += work;
147
		err = pthread_create(&p->pthread, NULL, preload_thread, p);
148

149
		if (err)
150
			die(_("unable to create threaded lstat: %s"), strerror(err));
151
	}
152
	for (i = 0; i < threads; i++) {
153
		struct thread_data *p = data+i;
154
		if (pthread_join(p->pthread, NULL))
155
			die("unable to join threaded lstat");
156
		t2_sum_lstat += p->t2_nr_lstat;
157
	}
158
	stop_progress(&pd.progress);
159

160
	if (pathspec) {
161
		/* earlier we made deep copies for each thread to work with */
162
		for (i = 0; i < threads; i++)
163
			clear_pathspec(&data[i].pathspec);
164
	}
165

166
	trace_performance_leave("preload index");
167

168
	trace2_data_intmax("index", NULL, "preload/sum_lstat", t2_sum_lstat);
169
	trace2_region_leave("index", "preload", NULL);
170
}
171

172
int repo_read_index_preload(struct repository *repo,
173
			    const struct pathspec *pathspec,
174
			    unsigned int refresh_flags)
175
{
176
	int retval = repo_read_index(repo);
177

178
	preload_index(repo->index, pathspec, refresh_flags);
179
	return retval;
180
}
181