Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756753AbYLESgs (ORCPT ); Fri, 5 Dec 2008 13:36:48 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753418AbYLESgk (ORCPT ); Fri, 5 Dec 2008 13:36:40 -0500 Received: from smtp-out.google.com ([216.239.45.13]:11032 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752652AbYLESgj (ORCPT ); Fri, 5 Dec 2008 13:36:39 -0500 DomainKey-Signature: a=rsa-sha1; s=beta; d=google.com; c=nofws; q=dns; h=mime-version:in-reply-to:references:date:message-id:subject:from:to: cc:content-type:content-transfer-encoding; b=gRn/3aQtO+9qCiW1sa/uy4f5wQIebqRVCm/X8KO+5ePMYt5yBiI5Cjkfe78z+sPch 1b11l3ZxSnet4W7yuSCBg== MIME-Version: 1.0 In-Reply-To: References: <5df78e1d0812021626y68c7241ahfdba4d37c7840e10@mail.gmail.com> <1228278908.4886.49.camel@localhost.localdomain> <5df78e1d0812022130g7c5a004bnd729d0a8454f24ed@mail.gmail.com> <5df78e1d0812050004q505cba8dnee39997a84d67847@mail.gmail.com> Date: Fri, 5 Dec 2008 10:36:34 -0800 Message-ID: <5df78e1d0812051036v6a619c2end01138b60217a74e@mail.gmail.com> Subject: Re: [RFC PATCH 3/3] kernel tracing prototype From: Jiaying Zhang To: "Frank Ch. Eigler" Cc: Steven Rostedt , linux-kernel@vger.kernel.org, Michael Rubin , Martin Bligh , Michael Davidson , Andrew Morton Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1533 Lines: 44 On Fri, Dec 5, 2008 at 7:34 AM, Frank Ch. Eigler wrote: > Jiaying Zhang writes: > >> To better answer the question why we want to implement a new kernel >> tracing prototype, here are some performance results we collected before >> with the tbench benchmark. > > Thanks. > >> - vanilla 2.6.26 kernel, CONFIG_MARKERS=n >> Throughput 759.352 MB/sec 4 >> - markers compiled in, tracing disabled >> Throughput 754.18 MB/sec 4 > > Is your kernel built with -freorder-blocks? This option dramatically > reduces the cost of inactive markers/tracepoints. No. I will try this this flag and let you know if I see any performance difference. Thanks for your suggestion! > >> - tracing syscall entry/exit, use markers, not logging data to ring_buffer >> Throughput 715.68 MB/sec 4 >> - tracing syscall entry/exit, use markers, logging data to ring_buffer >> Throughput 654.056 MB/sec 4 > > (By the way, how are you doing syscall entry/exit tracing?) The way we trace syscall entry/exit is similar to the approach used in LTTng. When tracing is enabled, a special flag, TIF_KERNEL_TRACE is set so syscall entry and exit call special syscall_trace_enter and syscall_trace_exit that are patched to call trace_mark in our old prototype. Jiaying > > > - FChE > -- 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/