Hi Calvin
On 23/09/2022 00:29, Calvin Wan wrote:
During the iteration of the index entries in run_diff_files, whenever
a submodule is found and needs its status checked, a subprocess is
spawned for it. Instead of spawning the subprocess immediately and
waiting for its completion to continue, hold onto all submodules and
relevant information in a list. Then use that list to create tasks for
run_processes_parallel. Finished subprocesses pipe their output to
status_finish which parses it and sets the relevant variables.
Add config option status.parallelSubmodules to set the maximum number
of parallel jobs.
I suspect in the future we may want to parallelize other commands for
submodules in which case a more general name such as submodules.threads
might be a better choice. The speed up in the cover letter is
impressive, could this be safely enabled by default?
index fcf9c85947..c5147a7952 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -1468,6 +1468,12 @@ static int git_status_config(const char *k, const char *v, void *cb)
s->detect_rename = git_config_rename(k, v);
return 0;
}
+ if (!strcmp(k, "status.parallelsubmodules")) {
+ s->parallel_jobs_submodules = git_config_int(k, v);
+ if (s->parallel_jobs_submodules < 0)
+ die(_("status.parallelsubmodules cannot be negative"));
What does a value of zero mean?
diff --git a/diff-lib.c b/diff-lib.c
index 2e148b79e6..ec745755fc 100644
--- a/diff-lib.c
+++ b/diff-lib.c
-int run_diff_files(struct rev_info *revs, unsigned int option)
+int run_diff_files(struct rev_info *revs, unsigned int option, int parallel_jobs)
Another possibility would be to add a member to struct diff_opts, rather
than changing the function signature here, I'm wondering what the trade
offs of the two approaches are. Also seeing all the callers from other
commands being changed made me wonder if they would benefit from
parallelizing submodules as well. There aren't any tests - could we use
GIT_TRACE2 to check that we are running the submodule diffs in parallel?
Best Wishes
Phillip
