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Mon, 2 Mar 2026 13:54:20 -0500 (EST) From: Junio C Hamano To: Adrian Ratiu Cc: Jeff King , Patrick Steinhardt , git@vger.kernel.org Subject: Re: Performance regression in "update" hooks In-Reply-To: <87wlzu5cug.fsf@collabora.com> (Adrian Ratiu's message of "Mon, 02 Mar 2026 20:02:31 +0200") References: <87bjh673o0.fsf@gentoo.mail-host-address-is-not-set> <874imy7220.fsf@collabora.com> <20260302175052.GA28275@coredump.intra.peff.net> <87wlzu5cug.fsf@collabora.com> Date: Mon, 02 Mar 2026 10:54:19 -0800 Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Precedence: bulk X-Mailing-List: git@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain Adrian Ratiu writes: > On Mon, 02 Mar 2026, Jeff King wrote: >> On Mon, Mar 02, 2026 at 03:27:22PM +0100, Patrick Steinhardt wrote: >> >>> > > I don't have the benchmark setup and it might be easier for you to >>> > > confirm? >>> >>> All you need is a normal development infra and hyperfine. The >>> benchmarking scripts in the repo I linked should then "just work" with >>> the above invocation. >> >> Thanks, these were very cool and easy to use. >> >> Looking at the patch, my guess was that the problem is that we are now >> setting up and tearing down the sideband muxer for each hook invocation. >> This is expensive for the "update" hook, since it fires once per ref. > > I independently root caused it and came up with (mostly) the same fix, > so this is a very good confirmation, thanks! > > Please wait for my patch because it needs fixing it 3 places, for 3 > hooks which spin up/down no-op async threads. :) Thanks for working on the problem report and coming to a fix so quickly.