From: Jeff King <peff@peff.net>
To: Junio C Hamano <gitster@pobox.com>
Cc: Patrick Steinhardt <ps@pks.im>, git@vger.kernel.org
Subject: Re: [PATCH] refs: fix interleaving hook calls with reference-transaction hook
Date: Fri, 7 Aug 2020 15:00:24 -0400 [thread overview]
Message-ID: <20200807190024.GA1307861@coredump.intra.peff.net> (raw)
In-Reply-To: <xmqqpn82gy51.fsf@gitster.c.googlers.com>
On Fri, Aug 07, 2020 at 10:32:26AM -0700, Junio C Hamano wrote:
> >> Test HEAD^ HEAD
> >> --------------------------------------------------------------------
> >> 1400.2: update-ref 1.93(1.57+0.42) 1.91(1.55+0.42) -1.0%
> >> 1400.3: update-ref --stdin 0.07(0.02+0.05) 0.07(0.02+0.05) +0.0%
> >>
> >> Running it a second time gets me +0.5%. :)
> >
> > Yeah, it's also been my take that OS-level overhead is probably going to
> > matter more than those access calls, and I argued such back when I
> > proposed the hook. So I'm perfectly happy to see this caching mechanism
> > go.
>
> Is the above about negative cache? IOW, does the above demonstrate
> that one extra access() to make sure there is no hook does not hurt
> us anything?
Yes, those numbers are with no cache at all, and without a hook. So they
are measuring the cost of access() only.
-Peff
next prev parent reply other threads:[~2020-08-07 19:00 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-07 7:05 [PATCH] refs: fix interleaving hook calls with reference-transaction hook Patrick Steinhardt
2020-08-07 7:58 ` Jeff King
2020-08-07 9:04 ` Patrick Steinhardt
2020-08-07 9:32 ` Jeff King
2020-08-07 9:49 ` Patrick Steinhardt
2020-08-07 17:32 ` Junio C Hamano
2020-08-07 19:00 ` Jeff King [this message]
2020-08-07 18:21 ` Jeff King
2020-08-07 19:26 ` Junio C Hamano
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