From: Jacob Keller <jacob.keller@gmail.com>
To: Philip Oakley <philipoakley@iee.org>
Cc: Johannes Sixt <j6t@kdbg.org>, Stefan Beller <sbeller@google.com>,
Junio C Hamano <gitster@pobox.com>,
Johannes Schindelin <Johannes.Schindelin@gmx.de>,
Git mailing list <git@vger.kernel.org>,
Simon Ruderich <simon@ruderich.org>, Jeff King <peff@peff.net>
Subject: Re: [PATCH] compat: Allow static initializer for pthreads on Windows
Date: Fri, 28 Oct 2016 11:49:25 -0700 [thread overview]
Message-ID: <CA+P7+xoNSrhaQ50GZ4RzLregznw+0yf2=ttNuYf1VUw+YabdFQ@mail.gmail.com> (raw)
In-Reply-To: <B5FD05E58E36480894F1BDBBC9589EE1@PhilipOakley>
On Fri, Oct 28, 2016 at 6:01 AM, Philip Oakley <philipoakley@iee.org> wrote:
> From: "Johannes Sixt" <j6t@kdbg.org>
>>
>>
>> One point is that the DCLP idiom must be implemented correctly. There are
>> solutions, of course, and when the initialization is over, we have a
>> miniscule overhead at each pthread_mutex_lock call.
>>
>
> I had to look up DCLP ( = Double Checked Locking Patterns), and found a good
> write up on the issues..
>
> http://www.aristeia.com/Papers/DDJ_Jul_Aug_2004_revised.pdf "C++ and the
> Perils of Double-Checked Locking", which include 'C' issues, and
> multi-thread, multi-processor issues. Not an easy issue when fighting
> optimisers..
>
> --
>
> Philip
Yep, this is why we have memory barriers. Ofcourse languages like C
don't really allow you to express them in the language and we restore
to various platform specific methods.
Thanks,
Jake
next prev parent reply other threads:[~2016-10-28 18:49 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-26 21:57 [PATCH] compat: Allow static initializer for pthreads on Windows Stefan Beller
2016-10-26 22:14 ` Stefan Beller
2016-10-27 5:49 ` Johannes Sixt
2016-10-27 6:02 ` Junio C Hamano
2016-10-27 6:10 ` Johannes Sixt
2016-10-27 6:21 ` Junio C Hamano
2016-10-27 6:29 ` Johannes Sixt
2016-10-27 6:33 ` Junio C Hamano
2016-10-27 17:01 ` Stefan Beller
2016-10-27 17:11 ` Jeff King
2016-10-27 18:22 ` Johannes Sixt
2016-10-27 18:49 ` Junio C Hamano
2016-10-27 19:08 ` Stefan Beller
2016-10-27 20:05 ` Johannes Sixt
2016-10-27 21:49 ` Jacob Keller
2016-10-27 21:59 ` Stefan Beller
2016-10-28 5:55 ` Johannes Sixt
2016-10-28 6:11 ` Jacob Keller
2016-10-28 13:01 ` Philip Oakley
2016-10-28 18:49 ` Jacob Keller [this message]
2016-10-28 11:58 ` Johannes Schindelin
2016-10-28 18:48 ` Jacob Keller
2016-10-28 20:26 ` Johannes Sixt
2016-10-28 20:29 ` Junio C Hamano
2016-10-28 20:36 ` Stefan Beller
2016-10-28 20:38 ` Junio C Hamano
2016-10-28 20:49 ` Johannes Sixt
2016-10-28 20:52 ` Junio C Hamano
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