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From: Brandon Williams <bmwill@google•com>
To: Jeff King <peff@peff•net>
Cc: Junio C Hamano <gitster@pobox•com>, git@vger•kernel.org
Subject: Re: What's cooking in git.git (Nov 2016, #06; Mon, 28)
Date: Wed, 30 Nov 2016 11:54:27 -0800	[thread overview]
Message-ID: <20161130195427.GA166433@google.com> (raw)
In-Reply-To: <20161129065125.cwlbkctniy7oshj2@sigill.intra.peff.net>

On 11/29, Jeff King wrote:
> On Tue, Nov 29, 2016 at 01:37:59AM -0500, Jeff King wrote:
> 
> >   2. Grep threads doing more complicated stuff that needs to take a
> >      lock. You might try building with -fsanitize=thread to see if it
> >      turns up anything.
> 
> I tried this and it didn't find anything useful. It complains about
> multiple threads calling want_color() at the same time, which you can
> silence with something like:
> 
> diff --git a/builtin/grep.c b/builtin/grep.c
> index 2c727ef49..d48846f40 100644
> --- a/builtin/grep.c
> +++ b/builtin/grep.c
> @@ -207,6 +207,12 @@ static void start_threads(struct grep_opt *opt)
>  {
>  	int i;
>  
> +	/*
> +	 * trigger want_color() for its side effect of caching the result;
> +	 * otherwise the threads will fight over setting the cache
> +	 */
> +	want_color(GIT_COLOR_AUTO);
> +
>  	pthread_mutex_init(&grep_mutex, NULL);
>  	pthread_mutex_init(&grep_read_mutex, NULL);
>  	pthread_mutex_init(&grep_attr_mutex, NULL);
> 
> But the problem persists even with that patch, so it is something else.
> It may still be a threading problem; -fsanitize=thread isn't perfect. I
> also couldn't get the stress-test to fail when compiled with it. But
> that may simply mean that the timing of the resulting binary is changed
> enough not to trigger the issue.
> 
> -Peff

With you're stress script I'm able to see the failures.  The interesting
thing is that the entry missing is always from the non-submodule file.

-- 
Brandon Williams

  reply	other threads:[~2016-11-30 19:54 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-11-29  0:15 What's cooking in git.git (Nov 2016, #06; Mon, 28) Junio C Hamano
2016-11-29  1:05 ` Brandon Williams
2016-11-29  6:37   ` Jeff King
2016-11-29  6:51     ` Jeff King
2016-11-30 19:54       ` Brandon Williams [this message]
2016-11-30 23:28         ` Brandon Williams
2016-11-30 23:32           ` Jeff King
2016-11-30 23:40             ` Jeff King
2016-11-30 23:42               ` Brandon Williams
2016-11-30 23:46                 ` Jeff King
2016-11-30 23:57                   ` Brandon Williams
2016-11-30 23:59                   ` Jeff King
2016-12-01  0:04                     ` Jeff King
2016-12-01  0:08                       ` Brandon Williams
2016-12-01  0:14                         ` Stefan Beller
2016-12-01  1:14                           ` Brandon Williams
2016-12-01  0:06                     ` Brandon Williams
2016-12-01  0:19                       ` Jeff King
2016-11-30 23:43               ` Stefan Beller
2016-12-01  7:09               ` Johannes Sixt
2016-12-01  7:19                 ` Jeff King
2016-11-29  6:59 ` Jeff King
2016-11-29 18:31   ` Junio C Hamano
2016-11-29 18:37     ` Jeff King
2016-11-29 19:21 ` Stefan Beller
2016-11-29 19:26   ` Junio C Hamano
2016-11-29 19:29     ` Stefan Beller
2016-11-30  0:25   ` Stefan Beller
2016-12-01  8:30 ` bw/transport-protocol-policy Jeff King
2016-12-01 18:14   ` bw/transport-protocol-policy Brandon Williams
2016-12-01 19:20     ` bw/transport-protocol-policy Jeff King
2016-12-01 19:35       ` bw/transport-protocol-policy Brandon Williams
2016-12-01 19:46         ` bw/transport-protocol-policy Jeff King
2016-12-01 19:53           ` bw/transport-protocol-policy Brandon Williams

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