Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S268458AbUILFhs (ORCPT ); Sun, 12 Sep 2004 01:37:48 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S268479AbUILFhs (ORCPT ); Sun, 12 Sep 2004 01:37:48 -0400 Received: from smtp204.mail.sc5.yahoo.com ([216.136.130.127]:57678 "HELO smtp204.mail.sc5.yahoo.com") by vger.kernel.org with SMTP id S268458AbUILFhp (ORCPT ); Sun, 12 Sep 2004 01:37:45 -0400 Message-ID: <4143D491.6070006@yahoo.com.au> Date: Sun, 12 Sep 2004 14:46:09 +1000 From: Nick Piggin User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.2) Gecko/20040810 Debian/1.7.2-2 X-Accept-Language: en MIME-Version: 1.0 To: Zwane Mwaikambo CC: Andrew Morton , torvalds@osdl.org, paulus@samba.org, linux-kernel@vger.kernel.org, anton@samba.org, jun.nakajima@intel.com, ak@suse.de, mingo@elte.hu Subject: Re: [PATCH] Yielding processor resources during lock contention References: <16703.60725.153052.169532@cargo.ozlabs.ibm.com> <20040911220003.0e9061ad.akpm@osdl.org> <4143D16F.30500@yahoo.com.au> In-Reply-To: Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 842 Lines: 22 Zwane Mwaikambo wrote: > On Sun, 12 Sep 2004, Nick Piggin wrote: >>I presume the hypervisor switch much incur the same sorts of costs as >>a context switch? > > > In the PPC64 and P4/HT case the spinning on a lock is a bad utilisation of > the execution resources and that's what we're really trying to avoid, not > necessarily cache thrashing from a context switch. > But isn't yielding to the hypervisor and thus causing it to schedule something else basically the same as a context switch? (I don't know anything about POWER). If yes, then shouldn't your lock be a blocking lock anyway? - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/