From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751499Ab2FLChF (ORCPT ); Mon, 11 Jun 2012 22:37:05 -0400 Received: from mail9.hitachi.co.jp ([133.145.228.44]:34697 "EHLO mail9.hitachi.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751054Ab2FLChD (ORCPT ); Mon, 11 Jun 2012 22:37:03 -0400 X-AuditID: b753bd60-9f483ba000000655-e6-4fd6ab4c19d5 X-AuditID: b753bd60-9f483ba000000655-e6-4fd6ab4c19d5 Message-ID: <4FD6AB49.3010809@hitachi.com> Date: Tue, 12 Jun 2012 11:36:57 +0900 From: Yoshihiro YUNOMAE Reply-To: yoshihiro.yunomae.ez@hitachi.com User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:12.0) Gecko/20120428 Thunderbird/12.0.1 MIME-Version: 1.0 To: Mathieu Desnoyers Cc: linux-kernel@vger.kernel.org, Masami Hiramatsu , Steven Rostedt , Peter Zijlstra , Ingo Molnar Subject: Re: ivring driver References: <20120605152947.GA21787@Krystal> In-Reply-To: <20120605152947.GA21787@Krystal> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Brightmail-Tracker: AAAAAA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org (2012/06/06 0:29), Mathieu Desnoyers wrote: > Hi Yoshihiro, > > I stumbled on your post on ivring (https://lkml.org/lkml/2012/6/5/143) > for buffering trace data from guest to host. I notice that it would be > very interesting to see a comparison of its performance against: > > - ftrace ring buffer > - perf ring buffer > - lttng 2.0 ring buffer > - lttng-ust 2.0 (user-space tracing) ring buffer Hi Mathieu. Thank you for commenting on how to compare among ring-buffer's performances. And sorry, I'm late for replying to you. > Comparing only with network-related mechanisms does not seem to provide > a complete picture of where it stands wrt other ring buffers out there. > > One of the metric we have used in the past is the number of nanoseconds > it takes to write a single event, based on a test that writes lots of > events into various buffer sizes, into flight recorder mode buffers > (which overwrites oldest information on buffer full condition, with data > collection to disk disabled, to remove I/O from the picture -- I/O can > then be performed in "snapshot" mode, after some error condition is > detected). OK, I see. When the overhead of ring-buffers will be evaluated in the next, I may use the metric as a reference. Thank you, -- Yoshihiro YUNOMAE Software Platform Research Dept. Linux Technology Center Hitachi, Ltd., Yokohama Research Laboratory E-mail: yoshihiro.yunomae.ez@hitachi.com