From mboxrd@z Thu Jan 1 00:00:00 1970 From: Folkert van Heusden Subject: Re: [GIT PULL] adaptive spinning mutexes Date: Fri, 16 Jan 2009 15:07:34 +0100 Message-ID: <20090116140734.GG29002@vanheusden.com> References: <1231952436.14825.28.camel@laptop> <20090114183319.GA18630@elte.hu> <20090114184746.GA21334@elte.hu> <20090114192811.GA19691@elte.hu> <20090115174440.GF29283@parisc-linux.org> <20090115180844.GL22472@elte.hu> <20090116005351.GD6763@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: "Paul E. McKenney" , Ingo Molnar , Matthew Wilcox , Peter Zijlstra , Gregory Haskins , Andi Kleen , Chris Mason , Andrew Morton , Linux Kernel Mailing List , linux-fsdevel , linux-btrfs , Thomas Gleixner , Nick Piggin , Peter Morreale , Sven Dietrich , Dmitry Adamushko , Johannes Weiner To: Linus Torvalds Return-path: Received: from smtp-vbr1.xs4all.nl ([194.109.24.21]:1529 "EHLO smtp-vbr1.xs4all.nl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1764921AbZAPOIh (ORCPT ); Fri, 16 Jan 2009 09:08:37 -0500 Content-Disposition: inline In-Reply-To: Sender: linux-fsdevel-owner@vger.kernel.org List-ID: > So I don't dispute at all that "mutex with spinning" performs better than > a mutex, but I _do_ claim that it has some potentially huge downsides > compared to a real spinlock. It may perform as well as a spinlock in the > nice common case, but then when you hit the non-common case you see the > difference between well-written code and badly written code. Make it mount-point dependant. Then your mail-spool can use the spinlock version and e.g. the /usr filesystem uses regular mutexes. Might be tricky to implement I guess. Folkert van Heusden -- MultiTail cok yonlu kullanimli bir program, loglari okumak, verilen kommandolari yerine getirebilen. Filter, renk verme, merge, 'diff- view', vs. http://www.vanheusden.com/multitail/ ---------------------------------------------------------------------- Phone: +31-6-41278122, PGP-key: 1F28D8AE, www.vanheusden.com