In builtin/grep.c:add_work() we pre-load the userdiff drivers before
adding the grep_source in the todo list. This operation is currently
being performed after acquiring the grep_mutex, but as it's already
thread-safe, we don't need to protect it here. So let's move it out of
the critical section which should avoid thread contention and improve
performance.
Running[1] `git grep --threads=8 abcd[02] HEAD` on chromium's
repository[2], I got the following mean times for 30 executions after 2
warmups:
Original | 6.2886s
-------------------------|-----------
Out of critical section | 5.7852s
[1]: Tests performed on an i7-7700HQ with 16GB of RAM and SSD, running
Manjaro Linux.
[2]: chromium’s repo at commit 03ae96f (“Add filters testing at DSF=2”,
04-06-2019), after a 'git gc' execution.
Signed-off-by: Matheus Tavares <[email protected]>
---
builtin/grep.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/builtin/grep.c b/builtin/grep.c
index 163f14b60d..d275b76647 100644
--- a/builtin/grep.c
+++ b/builtin/grep.c
@@ -92,8 +92,11 @@ static pthread_cond_t cond_result;
static int skip_first_line;
-static void add_work(struct grep_opt *opt, const struct grep_source *gs)
+static void add_work(struct grep_opt *opt, struct grep_source *gs)
{
+ if (opt->binary != GREP_BINARY_TEXT)
+ grep_source_load_driver(gs, opt->repo->index);
+
grep_lock();
while ((todo_end+1) % ARRAY_SIZE(todo) == todo_done) {
@@ -101,9 +104,6 @@ static void add_work(struct grep_opt *opt, const struct
grep_source *gs)
}
todo[todo_end].source = *gs;
- if (opt->binary != GREP_BINARY_TEXT)
- grep_source_load_driver(&todo[todo_end].source,
- opt->repo->index);
todo[todo_end].done = 0;
strbuf_reset(&todo[todo_end].out);
todo_end = (todo_end + 1) % ARRAY_SIZE(todo);
--
2.23.0
