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From: Jeff King <peff@peff.net>
To: Patrick Steinhardt <ps@pks.im>
Cc: git@vger.kernel.org
Subject: Re: [PATCH 2/2] p1400: Use `git-update-ref --stdin` to test multiple transactions
Date: Thu, 5 Nov 2020 14:34:55 -0500	[thread overview]
Message-ID: <20201105193455.GB121650@coredump.intra.peff.net> (raw)
In-Reply-To: <bfaac619112b04aa6545f229ea60433cbf8da73a.1604501265.git.ps@pks.im>

On Wed, Nov 04, 2020 at 03:57:22PM +0100, Patrick Steinhardt wrote:

> In commit 0a0fbbe3ff (refs: remove lookup cache for
> reference-transaction hook, 2020-08-25), a new benchmark was added to
> p1400 which has the intention to exercise creation of multiple
> transactions in a single process. As git-update-ref wasn't yet able to
> create multiple transactions with a single run we instead used git-push.
> As its non-atomic version creates a transaction per reference update,
> this was the best approximation we could make at that point in time.
> 
> Now that `git-update-ref --stdin` supports creation of multiple
> transactions, let's convert the benchmark to use that instead. It has
> less overhead and it's also a lot clearer what the actual intention is.

Good direction. The diff confused me for a moment...

> @@ -26,14 +27,7 @@ test_perf "update-ref" '
>  '
>  
>  test_perf "update-ref --stdin" '
> -	git update-ref --stdin <update &&
> -	git update-ref --stdin <delete &&
> -	git update-ref --stdin <create
> -'
> -
> -test_perf "nonatomic push" '
> -	git push ./target-repo.git $(test_seq 1000) &&
> -	git push --delete ./target-repo.git $(test_seq 1000)
> +	git update-ref --stdin <instructions >/dev/null
>  '

...because we're dropping _two_ tests here. But I think they were
testing the same thing, just with varying degrees of quality.

It could possibly be useful to have perf results broken down by
operation type (create vs delete vs update), but the original certainly
didn't do that. And it's not clear to me it would actually produce
interesting results; certainly not related to the hook, but possibly
related to benchmarking ref updates in general. So I don't think it's
worth worrying about.

-Peff

  reply	other threads:[~2020-11-05 19:35 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-04 14:57 [PATCH 0/2] update-ref: Allow creation of multiple transactions Patrick Steinhardt
2020-11-04 14:57 ` [PATCH 1/2] " Patrick Steinhardt
2020-11-05 19:29   ` Jeff King
2020-11-05 21:34     ` Junio C Hamano
2020-11-06 17:52       ` Jeff King
2020-11-06 19:30         ` Junio C Hamano
2020-11-06  6:36     ` Patrick Steinhardt
2020-11-04 14:57 ` [PATCH 2/2] p1400: Use `git-update-ref --stdin` to test " Patrick Steinhardt
2020-11-05 19:34   ` Jeff King [this message]
2020-11-09 10:06 ` [PATCH v2 0/4] update-ref: Allow creation of " Patrick Steinhardt
2020-11-09 10:06   ` [PATCH v2 1/4] t1400: Avoid touching refs on filesystem Patrick Steinhardt
2020-11-09 19:48     ` Junio C Hamano
2020-11-09 22:28       ` Jeff King
2020-11-10 12:34       ` Patrick Steinhardt
2020-11-10 17:04         ` Junio C Hamano
2020-11-09 10:06   ` [PATCH v2 2/4] update-ref: Allow creation of multiple transactions Patrick Steinhardt
2020-11-09 10:06   ` [PATCH v2 3/4] p1400: Use `git-update-ref --stdin` to test " Patrick Steinhardt
2020-11-09 10:07   ` [PATCH v2 4/4] update-ref: Disallow restart of ongoing transactions Patrick Steinhardt
2020-11-09 19:53     ` Junio C Hamano
2020-11-09 22:33   ` [PATCH v2 0/4] update-ref: Allow creation of multiple transactions Jeff King
2020-11-09 22:38     ` Junio C Hamano
2020-11-11  6:58 ` [PATCH v3 0/4] update-ref: allow " Patrick Steinhardt
2020-11-11  6:58   ` [PATCH v3 1/4] t1400: avoid touching refs on filesystem Patrick Steinhardt
2020-11-11  9:04     ` SZEDER Gábor
2020-11-11 10:00       ` Patrick Steinhardt
2020-11-11 10:24         ` SZEDER Gábor
2020-11-11 23:06     ` Jeff King
2020-11-13  8:08       ` Patrick Steinhardt
2020-11-11  6:58   ` [PATCH v3 2/4] update-ref: allow creation of multiple transactions Patrick Steinhardt
2020-11-11  6:58   ` [PATCH v3 3/4] p1400: use `git-update-ref --stdin` to test " Patrick Steinhardt
2020-11-11  6:58   ` [PATCH v3 4/4] update-ref: disallow "start" for ongoing transactions Patrick Steinhardt
2020-11-13  8:12 ` [PATCH v4 0/4] update-ref: allow creation of multiple transactions Patrick Steinhardt
2020-11-13  8:12   ` [PATCH v4 1/4] t1400: avoid touching refs on filesystem Patrick Steinhardt
2020-11-13 20:40     ` Jeff King
2020-11-18  6:48       ` Patrick Steinhardt
2020-11-18  7:02         ` Junio C Hamano
2020-11-13  8:12   ` [PATCH v4 2/4] update-ref: allow creation of multiple transactions Patrick Steinhardt
2020-11-13  8:12   ` [PATCH v4 3/4] p1400: use `git-update-ref --stdin` to test " Patrick Steinhardt
2020-11-13  8:12   ` [PATCH v4 4/4] update-ref: disallow "start" for ongoing transactions Patrick Steinhardt
2020-11-25 22:37   ` [PATCH v4 0/4] update-ref: allow creation of multiple transactions Junio C Hamano
2020-11-26  0:42     ` Jeff King

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