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Subject: Re: [PATCH v2 3/3] grep: disable threading in all but worktree case
Date: Fri, 23 Dec 2011 23:37:55 +0100
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References: <cover.1322830368.git.trast@student.ethz.ch> <5328add8b32f83b4cdbd2e66283f77c125ec127a.1322830368.git.trast@student.ethz.ch>
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	Eric Herman <eric@freesa.org>, git@vger.kernel.org,
	Junio C Hamano <gitster@pobox.com>,
	Fredrik Kuivinen <frekui@gmail.com>
To: Thomas Rast <trast@student.ethz.ch>
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On Fri, Dec 2, 2011 at 14:07, Thomas Rast <trast@student.ethz.ch> wrote:

> I conjecture that this is caused by contention on
> read_sha1_mutex. [...] So disable threading entirely when not
> scanning the worktree

Why does git-grep even need to keep a mutex to call read_sha1_file()?
It's inherently a read-only operation isn't it? If the lock is needed
because data is being shared between threads in sha1_file.c shouldn't
we tackle that instead of completely disabling threading?