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From: Junio C Hamano <gitster@pobox.com>
To: Phillip Wood <phillip.wood123@gmail.com>
Cc: "Calvin Wan" <calvinwan@google.com>,
	git@vger.kernel.org, emilyshaffer@google.com,
	"Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
Subject: Re: [PATCH 4/4] diff-lib: parallelize run_diff_files for submodules
Date: Mon, 26 Sep 2022 10:11:21 -0700	[thread overview]
Message-ID: <xmqqedvyqcw6.fsf@gitster.g> (raw)
In-Reply-To: <88b194d9-7c78-c12e-1c29-95f768db7772@gmail.com> (Phillip Wood's message of "Sun, 25 Sep 2022 14:59:15 +0100")

Phillip Wood <phillip.wood123@gmail.com> writes:

>> +	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?

Good question.  I don't remember what the code in the patch I read
actually does, but I would imagine we would want to be able to say:

 - I do not trust the parallel mode yet, just use the single process
   method that we have always been using.

 - I do not know how many cores I have, just use a reasonable
   default parallelism.

 - I want to use N processes because I know better than auto-scaling
   based on num_cpus.

And the value of 1 would be a reasonable way to express the first
one, and 0 would be a reasonable thing to do for the second one.

>> -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,

Yes, absolutely.  Somewhere that is reachable from rev_info
structure would be more appropriate.

Thanks.

  reply	other threads:[~2022-09-26 17:44 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-22 23:29 [PATCH 0/4] submodule: parallelize status Calvin Wan
2022-09-22 23:29 ` [PATCH 1/4] run-command: add pipe_output to run_processes_parallel Calvin Wan
2022-09-23  7:52   ` Ævar Arnfjörð Bjarmason
2022-09-26 16:59     ` Calvin Wan
2022-09-27 10:52       ` Ævar Arnfjörð Bjarmason
2022-09-23 18:58   ` Junio C Hamano
2022-09-26 17:31     ` Calvin Wan
2022-09-27  4:45       ` Junio C Hamano
2022-09-27 18:10         ` Calvin Wan
2022-09-27 21:40           ` Junio C Hamano
2022-09-27  9:05       ` Ævar Arnfjörð Bjarmason
2022-09-27 17:55         ` Calvin Wan
2022-09-27 19:34           ` Ævar Arnfjörð Bjarmason
2022-09-27 20:45             ` Calvin Wan
2022-09-28  5:40               ` Ævar Arnfjörð Bjarmason
2022-09-29 20:52                 ` Calvin Wan
2022-09-22 23:29 ` [PATCH 2/4] submodule: move status parsing into function Calvin Wan
2022-09-22 23:29 ` [PATCH 3/4] diff-lib: refactor functions Calvin Wan
2022-09-23 20:36   ` Junio C Hamano
2022-09-26 17:35     ` Calvin Wan
2022-09-22 23:29 ` [PATCH 4/4] diff-lib: parallelize run_diff_files for submodules Calvin Wan
2022-09-23  8:06   ` Ævar Arnfjörð Bjarmason
2022-09-24 20:17     ` Junio C Hamano
2022-09-26 17:50     ` Calvin Wan
2022-09-23 21:44   ` Junio C Hamano
2022-09-26 19:12     ` Calvin Wan
2022-09-25 13:59   ` Phillip Wood
2022-09-26 17:11     ` Junio C Hamano [this message]
2022-09-26 19:22     ` Calvin Wan
2022-09-27 18:40   ` Emily Shaffer
2022-09-23 22:56 ` [PATCH 0/4] submodule: parallelize status Junio C Hamano
2022-09-26 16:33   ` Calvin Wan

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