RE: [External Mail]Re: why git is so slow for a tiny git push?

From: 程洋 <chengyang@xiaomi.com>
Date: Oct 14, 2021, 06:47 UTC
Message-ID: <5063751fd4b94ccca3987080c96370d8@xiaomi.com>
In-Reply-To: <YWYAjRfLsDtc1Dkm@coredump.intra.peff.net>

Seems that git receive-pack only takes 1 seconds. After that, git rev-list takes the most time, I don't know what is it doing

-----Original Message-----
From: Jeff King <peff@peff.net>
Sent: Wednesday, October 13, 2021 5:39 AM
To: 程洋 <chengyang@xiaomi.com>
Cc: git@vger.kernel.org
Subject: Re: [External Mail]Re: why git is so slow for a tiny git push?

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On Tue, Oct 12, 2021 at 09:08:08AM +0000, 程洋 wrote:

Show 6 quoted lines

> Jesus. It works for me. After disable writebitmap, time cost decrease
> from 33 seconds to 0.9 seconds.
>
> But now it turns out that, remote side takes 13 seconds to receive the
> pack,  since git receive-pack is triggered automatically from remote
> side, is there anyway to enable GIT_TRACE2_PERF on server side?

For the environment variable, it depends on your protocol. If you can push over ssh (and the other side lets you execute arbitrary commands), then:

  git push --receive-pack='GIT_TRACE2_PERF=/tmp/foo.trace git-receive-pack'

Otherwise, you can look at setting the trace2.perfTarget config option on the server side. I haven't played with it myself before.

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