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![Jeff Hostetler](/assets/img/avatar_default.png)
Report the total number of calls made to lstat() inside preload_index(). FSMonitor improves the performance of commands like `git status` by avoiding scanning the disk for changed files. This can be seen in `preload_index()`. Let's measure this. Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com> Reviewed-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
169 lines
4 KiB
C
169 lines
4 KiB
C
/*
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* Copyright (C) 2008 Linus Torvalds
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*/
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#include "cache.h"
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#include "pathspec.h"
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#include "dir.h"
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#include "fsmonitor.h"
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#include "config.h"
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#include "progress.h"
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#include "thread-utils.h"
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#include "repository.h"
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/*
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* Mostly randomly chosen maximum thread counts: we
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* cap the parallelism to 20 threads, and we want
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* to have at least 500 lstat's per thread for it to
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* be worth starting a thread.
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*/
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#define MAX_PARALLEL (20)
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#define THREAD_COST (500)
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struct progress_data {
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unsigned long n;
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struct progress *progress;
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pthread_mutex_t mutex;
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};
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struct thread_data {
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pthread_t pthread;
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struct index_state *index;
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struct pathspec pathspec;
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struct progress_data *progress;
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int offset, nr;
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int t2_nr_lstat;
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};
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static void *preload_thread(void *_data)
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{
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int nr, last_nr;
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struct thread_data *p = _data;
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struct index_state *index = p->index;
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struct cache_entry **cep = index->cache + p->offset;
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struct cache_def cache = CACHE_DEF_INIT;
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nr = p->nr;
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if (nr + p->offset > index->cache_nr)
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nr = index->cache_nr - p->offset;
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last_nr = nr;
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do {
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struct cache_entry *ce = *cep++;
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struct stat st;
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if (ce_stage(ce))
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continue;
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if (S_ISGITLINK(ce->ce_mode))
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continue;
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if (ce_uptodate(ce))
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continue;
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if (ce_skip_worktree(ce))
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continue;
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if (ce->ce_flags & CE_FSMONITOR_VALID)
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continue;
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if (p->progress && !(nr & 31)) {
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struct progress_data *pd = p->progress;
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pthread_mutex_lock(&pd->mutex);
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pd->n += last_nr - nr;
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display_progress(pd->progress, pd->n);
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pthread_mutex_unlock(&pd->mutex);
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last_nr = nr;
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}
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if (!ce_path_match(index, ce, &p->pathspec, NULL))
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continue;
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if (threaded_has_symlink_leading_path(&cache, ce->name, ce_namelen(ce)))
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continue;
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p->t2_nr_lstat++;
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if (lstat(ce->name, &st))
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continue;
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if (ie_match_stat(index, ce, &st, CE_MATCH_RACY_IS_DIRTY|CE_MATCH_IGNORE_FSMONITOR))
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continue;
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ce_mark_uptodate(ce);
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mark_fsmonitor_valid(index, ce);
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} while (--nr > 0);
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if (p->progress) {
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struct progress_data *pd = p->progress;
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pthread_mutex_lock(&pd->mutex);
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display_progress(pd->progress, pd->n + last_nr);
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pthread_mutex_unlock(&pd->mutex);
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}
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cache_def_clear(&cache);
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return NULL;
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}
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void preload_index(struct index_state *index,
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const struct pathspec *pathspec,
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unsigned int refresh_flags)
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{
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int threads, i, work, offset;
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struct thread_data data[MAX_PARALLEL];
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struct progress_data pd;
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int t2_sum_lstat = 0;
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if (!HAVE_THREADS || !core_preload_index)
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return;
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threads = index->cache_nr / THREAD_COST;
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if ((index->cache_nr > 1) && (threads < 2) && git_env_bool("GIT_TEST_PRELOAD_INDEX", 0))
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threads = 2;
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if (threads < 2)
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return;
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trace2_region_enter("index", "preload", NULL);
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trace_performance_enter();
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if (threads > MAX_PARALLEL)
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threads = MAX_PARALLEL;
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offset = 0;
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work = DIV_ROUND_UP(index->cache_nr, threads);
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memset(&data, 0, sizeof(data));
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memset(&pd, 0, sizeof(pd));
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if (refresh_flags & REFRESH_PROGRESS && isatty(2)) {
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pd.progress = start_delayed_progress(_("Refreshing index"), index->cache_nr);
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pthread_mutex_init(&pd.mutex, NULL);
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}
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for (i = 0; i < threads; i++) {
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struct thread_data *p = data+i;
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int err;
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p->index = index;
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if (pathspec)
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copy_pathspec(&p->pathspec, pathspec);
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p->offset = offset;
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p->nr = work;
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if (pd.progress)
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p->progress = &pd;
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offset += work;
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err = pthread_create(&p->pthread, NULL, preload_thread, p);
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if (err)
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die(_("unable to create threaded lstat: %s"), strerror(err));
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}
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for (i = 0; i < threads; i++) {
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struct thread_data *p = data+i;
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if (pthread_join(p->pthread, NULL))
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die("unable to join threaded lstat");
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t2_sum_lstat += p->t2_nr_lstat;
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}
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stop_progress(&pd.progress);
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trace_performance_leave("preload index");
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trace2_data_intmax("index", NULL, "preload/sum_lstat", t2_sum_lstat);
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trace2_region_leave("index", "preload", NULL);
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}
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int repo_read_index_preload(struct repository *repo,
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const struct pathspec *pathspec,
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unsigned int refresh_flags)
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{
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int retval = repo_read_index(repo);
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preload_index(repo->index, pathspec, refresh_flags);
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return retval;
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}
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