From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758243AbZKYCIv (ORCPT ); Tue, 24 Nov 2009 21:08:51 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758185AbZKYCIu (ORCPT ); Tue, 24 Nov 2009 21:08:50 -0500 Received: from cn.fujitsu.com ([222.73.24.84]:65413 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1758174AbZKYCIu (ORCPT ); Tue, 24 Nov 2009 21:08:50 -0500 Message-ID: <4B0C918E.1070101@cn.fujitsu.com> Date: Wed, 25 Nov 2009 10:08:14 +0800 From: Lai Jiangshan User-Agent: Thunderbird 2.0.0.6 (Windows/20070728) MIME-Version: 1.0 To: Steven Rostedt CC: Frederic Weisbecker , Ingo Molnar , Jason Baron , LKML Subject: Re: [PATCH] tracing: separate raw syscall from syscall tracer References: <4AEFC37C.5080609@cn.fujitsu.com> <20091103082311.GA4815@nowhere> In-Reply-To: <20091103082311.GA4815@nowhere> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Frederic Weisbecker wrote: > On Tue, Nov 03, 2009 at 01:45:32PM +0800, Lai Jiangshan wrote: >> current syscall tracer mixes raw syscalls and real syscalls. >> >> echo 1 > events/syscalls/enable >> And we get these from the output: >> >> (XXXX insteads " grep-20914 [001] 588211.446347" .. etc) >> >> XXXX: sys_read(fd: 3, buf: 80609a8, count: 7000) >> XXXX: sys_enter: NR 3 (3, 80609a8, 7000, a, 1000, bfce8ef8) >> XXXX: sys_read -> 0x138 >> XXXX: sys_exit: NR 3 = 312 >> XXXX: sys_read(fd: 3, buf: 8060ae0, count: 7000) >> XXXX: sys_enter: NR 3 (3, 8060ae0, 7000, a, 1000, bfce8ef8) >> XXXX: sys_read -> 0x138 >> XXXX: sys_exit: NR 3 = 312 >> >> There are 2 drawbacks here. >> A) two almost identical records are saved in ringbuffer >> when a syscall enters or exits. (4 records for every syscall) >> it wastes too much. >> B) the lines include "sys_enter/sys_exit" makes >> we hardly get the useful information for the output. >> >> The user can use this method to prevent these drawbacks: >> echo 1 > events/syscalls/enable >> echo 0 > events/syscalls/sys_enter/enable >> echo 0 > events/syscalls/sys_exit/enable >> >> But it's not friendly for users. So we separate raw syscall >> from syscall tracer. >> >> After this fix applied: >> syscall tracer's output (echo 1 > events/syscalls/enable): >> >> XXXX: sys_read(fd: 3, buf: bfe87d88, count: 200) >> XXXX: sys_read -> 0x200 >> XXXX: sys_fstat64(fd: 3, statbuf: bfe87c98) >> XXXX: sys_fstat64 -> 0x0 >> XXXX: sys_close(fd: 3) >> >> raw syscall tracer's output (echo 1 > events/raw_syscalls/enable): >> >> XXXX: sys_enter: NR 175 (0, bf92bf18, bf92bf98, 8, b748cff4, bf92bef8) >> XXXX: sys_exit: NR 175 = 0 >> XXXX: sys_enter: NR 175 (2, bf92bf98, 0, 8, b748cff4, bf92bef8) >> XXXX: sys_exit: NR 175 = 0 >> XXXX: sys_enter: NR 3 (9, bf927f9c, 4000, b77e2518, b77dce60, bf92bff8) >> >> Signed-off-by: Lai Jiangshan >> --- > > > Agreed, that's indeed not convenient. > > Acked-by: Frederic Weisbecker > > > Hi, Steven Could you accept this patch? Lai