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e596acc23a
Teach preload-index to avoid lstat() calls for index-entries
with skip-worktree bit set. This is a performance optimization.
During a sparse-checkout, the skip-worktree bit is set on items
that were not populated and therefore are not present in the
worktree. The per-thread preload-index loop performs a series
of tests on each index-entry as it attempts to compare the
worktree version with the index and mark them up-to-date.
This patch short-cuts that work.
On a Windows 10 system with a very large repo (450MB index)
and various levels of sparseness, performance was improved
in the {preloadindex=true, fscache=false} case by 80% and
in the {preloadindex=true, fscache=true} case by 20% for various
commands.
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
115 lines
2.5 KiB
C
115 lines
2.5 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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#ifdef NO_PTHREADS
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static void preload_index(struct index_state *index,
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const struct pathspec *pathspec)
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{
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; /* nothing */
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}
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#else
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#include <pthread.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 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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int offset, nr;
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};
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static void *preload_thread(void *_data)
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{
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int 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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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_path_match(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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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))
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continue;
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ce_mark_uptodate(ce);
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} while (--nr > 0);
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cache_def_clear(&cache);
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return NULL;
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}
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static void preload_index(struct index_state *index,
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const struct pathspec *pathspec)
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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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if (!core_preload_index)
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return;
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threads = index->cache_nr / THREAD_COST;
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if (threads < 2)
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return;
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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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for (i = 0; i < threads; i++) {
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struct thread_data *p = data+i;
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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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offset += work;
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if (pthread_create(&p->pthread, NULL, preload_thread, p))
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die("unable to create threaded lstat");
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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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}
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}
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#endif
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int read_index_preload(struct index_state *index,
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const struct pathspec *pathspec)
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{
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int retval = read_index(index);
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preload_index(index, pathspec);
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return retval;
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}
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