From: Vincent Hanquez <vincent@xensource.com>
To: Peter Teoh <htmldeveloper@gmail.com>
Cc: xen-devel@lists.xensource.com
Subject: Re: pthread_mutex_lock() and Xenstored
Date: Thu, 13 Sep 2007 17:03:09 +0200 [thread overview]
Message-ID: <20070913150309.GA21282@snarc.org> (raw)
In-Reply-To: <05c801c7eb94$850ae780$9a010a0a@eeyore>
On Fri, Aug 31, 2007 at 01:51:18PM +0800, Peter Teoh wrote:
> pthread_mutex_lock() are not async-signal safe (ref:
> http://www.gelato.org/pdf/Illinois/gelato_IL2004_libatomic_boehm.pdf)
> but I still see that it is used extensively in xenstored
> implementation (eg, xs.c).
xs is the client part of the xenstore protocol. it's not used in
xenstored (the daemon).
> Moreover, pthread_mutex_lock() suffered a higher performance penalty
> than other synchronization option. For a one-time effort like domain
> creation this is ok, but Xenstore is used repeatedly to access data,
> and therefore performance could potentially be enhanced.
>
> Does all these sound logical?
Not really. xenstored is single threaded and has a file-backed-storage
anyway, so most of the time you're going to wait for that.
I expect the pthread_mutex_lock to be insignificant compared to the time
waiting for xenstored to reply. Also the xs interface is not meant to be
use massively in parallel.
Cheers,
--
Vincent Hanquez
next prev parent reply other threads:[~2007-09-13 15:03 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-08-31 5:51 pthread_mutex_lock() and Xenstored Peter Teoh
2007-09-13 15:03 ` Vincent Hanquez [this message]
2007-09-13 15:21 ` Daniel P. Berrange
2007-09-15 6:01 ` Peter Teoh
2007-09-15 9:48 ` Bastian Blank
2007-09-15 16:51 ` Peter Teoh
2007-09-15 13:50 ` Daniel P. Berrange
2007-09-15 17:57 ` John Levon
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