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git/preload-index.c
Ben Peart 3e2c66961a preload-index: add override to enable testing preload-index
By default, the preload index code path doesn't run unless there is a
minimum of 1000 files. To enable running the test suite and having it
execute the preload-index path, add an environment variable
(GIT_FORCE_PRELOAD_TEST) which will override that minimum and set it to 2.

This enables you run existing tests and have the core.preloadindex code
path execute as long as the test has at least 2 files by setting
GIT_FORCE_PRELOAD_TEXT=1 before running the test.

Signed-off-by: Ben Peart <benpeart@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-24 10:39:40 +09:00

118 lines
2.6 KiB
C

/*
* Copyright (C) 2008 Linus Torvalds
*/
#include "cache.h"
#include "pathspec.h"
#include "dir.h"
#ifdef NO_PTHREADS
static void preload_index(struct index_state *index,
const struct pathspec *pathspec)
{
; /* nothing */
}
#else
#include <pthread.h>
/*
* Mostly randomly chosen maximum thread counts: we
* cap the parallelism to 20 threads, and we want
* to have at least 500 lstat's per thread for it to
* be worth starting a thread.
*/
#define MAX_PARALLEL (20)
#define THREAD_COST (500)
struct thread_data {
pthread_t pthread;
struct index_state *index;
struct pathspec pathspec;
int offset, nr;
};
static void *preload_thread(void *_data)
{
int nr;
struct thread_data *p = _data;
struct index_state *index = p->index;
struct cache_entry **cep = index->cache + p->offset;
struct cache_def cache = CACHE_DEF_INIT;
nr = p->nr;
if (nr + p->offset > index->cache_nr)
nr = index->cache_nr - p->offset;
do {
struct cache_entry *ce = *cep++;
struct stat st;
if (ce_stage(ce))
continue;
if (S_ISGITLINK(ce->ce_mode))
continue;
if (ce_uptodate(ce))
continue;
if (ce_skip_worktree(ce))
continue;
if (!ce_path_match(ce, &p->pathspec, NULL))
continue;
if (threaded_has_symlink_leading_path(&cache, ce->name, ce_namelen(ce)))
continue;
if (lstat(ce->name, &st))
continue;
if (ie_match_stat(index, ce, &st, CE_MATCH_RACY_IS_DIRTY))
continue;
ce_mark_uptodate(ce);
} while (--nr > 0);
cache_def_clear(&cache);
return NULL;
}
static void preload_index(struct index_state *index,
const struct pathspec *pathspec)
{
int threads, i, work, offset;
struct thread_data data[MAX_PARALLEL];
if (!core_preload_index)
return;
threads = index->cache_nr / THREAD_COST;
if ((index->cache_nr > 1) && (threads < 2) && getenv("GIT_FORCE_PRELOAD_TEST"))
threads = 2;
if (threads < 2)
return;
if (threads > MAX_PARALLEL)
threads = MAX_PARALLEL;
offset = 0;
work = DIV_ROUND_UP(index->cache_nr, threads);
memset(&data, 0, sizeof(data));
for (i = 0; i < threads; i++) {
struct thread_data *p = data+i;
p->index = index;
if (pathspec)
copy_pathspec(&p->pathspec, pathspec);
p->offset = offset;
p->nr = work;
offset += work;
if (pthread_create(&p->pthread, NULL, preload_thread, p))
die("unable to create threaded lstat");
}
for (i = 0; i < threads; i++) {
struct thread_data *p = data+i;
if (pthread_join(p->pthread, NULL))
die("unable to join threaded lstat");
}
}
#endif
int read_index_preload(struct index_state *index,
const struct pathspec *pathspec)
{
int retval = read_index(index);
preload_index(index, pathspec);
return retval;
}