From: Jeff King <peff@peff.net>
To: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
Cc: Jonas Bernoulli <jonas@bernoul.li>, git@vger.kernel.org
Subject: Re: "submodule foreach" much slower than removed "submodule--helper --list"
Date: Mon, 17 Oct 2022 13:46:23 -0400 [thread overview]
Message-ID: <Y02U7611DH6zFsK9@coredump.intra.peff.net> (raw)
In-Reply-To: <221017.86h702jsiq.gmgdl@evledraar.gmail.com>
On Mon, Oct 17, 2022 at 06:50:06PM +0200, Ævar Arnfjörð Bjarmason wrote:
> Sorry about the slowdown, the removal of "list" was just an in-between
> step to migrating "submodule" to a full built-in.
>
> I can't reproduce anything like the 8ms v.s. ~600ms difference you note
> here, but for me migrating it to a built-in is around 10% slower with
> "foreach" than the old "list". I wonder what results you get?
I don't think "foreach" can ever be as performant as a bare "list". It
inherently is going to do O(n) fork+execs. So it's OK if you have one or
two submodules, but not if you have hundreds.
If it treated "echo" as a builtin and served it in-process, it could
avoid that extra overhead. But there are so many corner cases there,
you'd probably do better to add "list --format" instead.
-Peff
next prev parent reply other threads:[~2022-10-17 17:46 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-15 16:50 "submodule foreach" much slower than removed "submodule--helper --list" Jonas Bernoulli
2022-10-15 17:34 ` Jonas Bernoulli
2022-10-15 18:13 ` Jeff King
2022-10-15 18:16 ` Junio C Hamano
2022-10-15 18:23 ` Jeff King
2022-10-15 18:37 ` Junio C Hamano
2022-10-15 22:40 ` Junio C Hamano
2022-10-17 17:02 ` Jeff King
2022-11-07 11:01 ` Matti Möll
2022-11-08 2:50 ` Taylor Blau
2022-11-08 3:37 ` Ævar Arnfjörð Bjarmason
2022-10-17 16:50 ` Ævar Arnfjörð Bjarmason
2022-10-17 17:46 ` Jeff King [this message]
2022-10-21 14:58 ` Jonas Bernoulli
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