Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751852Ab0HBPUF (ORCPT ); Mon, 2 Aug 2010 11:20:05 -0400 Received: from claw.goop.org ([74.207.240.146]:56852 "EHLO claw.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751284Ab0HBPUD (ORCPT ); Mon, 2 Aug 2010 11:20:03 -0400 Message-ID: <4C56E221.6050800@goop.org> Date: Mon, 02 Aug 2010 08:20:01 -0700 From: Jeremy Fitzhardinge User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.7) Gecko/20100720 Fedora/3.1.1-1.fc13 Lightning/1.0b2pre Thunderbird/3.1.1 MIME-Version: 1.0 To: Avi Kivity CC: vatsa@linux.vnet.ibm.com, Marcelo Tosatti , Gleb Natapov , linux-kernel@vger.kernel.org, npiggin@suse.de, kvm@vger.kernel.org, bharata@in.ibm.com, Balbir Singh , Jan Beulich Subject: Re: [PATCH RFC 3/4] Paravirtualized spinlock implementation for KVM guests References: <20100726061150.GB21699@linux.vnet.ibm.com> <20100726061537.GC8402@linux.vnet.ibm.com> <4C568669.40001@redhat.com> In-Reply-To: <4C568669.40001@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1210 Lines: 41 On 08/02/2010 01:48 AM, Avi Kivity wrote: > On 07/26/2010 09:15 AM, Srivatsa Vaddagiri wrote: >> Paravirtual spinlock implementation for KVM guests, based heavily on >> Xen guest's >> spinlock implementation. >> >> >> + >> +static struct spinlock_stats >> +{ >> + u64 taken; >> + u32 taken_slow; >> + >> + u64 released; >> + >> +#define HISTO_BUCKETS 30 >> + u32 histo_spin_total[HISTO_BUCKETS+1]; >> + u32 histo_spin_spinning[HISTO_BUCKETS+1]; >> + u32 histo_spin_blocked[HISTO_BUCKETS+1]; >> + >> + u64 time_total; >> + u64 time_spinning; >> + u64 time_blocked; >> +} spinlock_stats; > > Could these be replaced by tracepoints when starting to spin/stopping > spinning etc? Then userspace can reconstruct the histogram as well as > see which locks are involved and what call paths. Unfortunately not; the tracing code uses spinlocks. (TBH I haven't actually tried, but I did give the code an eyeball to this end.) J -- 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/