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Re: why does rwlock prefer readers by default?
- From: OndÅej BÃlka <neleai at seznam dot cz>
- To: Torvald Riegel <triegel at redhat dot com>
- Cc: GLIBC Devel <libc-alpha at sourceware dot org>
- Date: Wed, 7 May 2014 13:25:36 +0200
- Subject: Re: why does rwlock prefer readers by default?
- Authentication-results: sourceware.org; auth=none
- References: <1399458831 dot 32485 dot 12625 dot camel at triegel dot csb>
On Wed, May 07, 2014 at 12:33:51PM +0200, Torvald Riegel wrote:
> POSIX makes it an implementation-defined choice whether readers or
> writers are preferred. Our current implementation's default is that
> readers are to be preferred. I couldn't find the rationale for this;
> does anybody know what it was?
>
> Otherwise, if this was an arbitrary choice, what do you all think the
> default should be? Can we change it? Should we change it to preferring
> writers?
See archives, original thread was here
https://sourceware.org/ml/libc-alpha/2013-07/msg00232.html
This was recently pinged in this thread.
https://sourceware.org/ml/libc-alpha/2014-04/msg00049.html
A relevant part from Wang's mail is following: "
Cyril Hrubis once reported a bug about pthread_rwlock() posix tests in
LTP:
https://sourceware.org/bugzilla/show_bug.cgi?id=13701
And there were some clarification requests for Austin Group about this
issue.
see:
http://austingroupbugs.net/view.php?id=720
http://austingroupbugs.net/view.php?id=722
According to the discussion results, it seems that write locks should be
implemented to take precedence before the read locks.
"