Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752640AbZAECJS (ORCPT ); Sun, 4 Jan 2009 21:09:18 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751526AbZAECJF (ORCPT ); Sun, 4 Jan 2009 21:09:05 -0500 Received: from cn.fujitsu.com ([222.73.24.84]:51794 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1751342AbZAECJE (ORCPT ); Sun, 4 Jan 2009 21:09:04 -0500 Message-ID: <49616B0B.5000102@cn.fujitsu.com> Date: Mon, 05 Jan 2009 10:06:03 +0800 From: Lai Jiangshan User-Agent: Thunderbird 2.0.0.18 (Windows/20081105) MIME-Version: 1.0 To: Frederic Weisbecker CC: Arnaldo Carvalho de Melo , Ingo Molnar , Steven Rostedt , Linux Kernel Mailing List Subject: Re: [PATCH 2/5] ftrace: infrastructure for supporting binary record References: <495ADF45.2030203@cn.fujitsu.com> <20081231045956.GC28472@nowhere> <39e6f6c70901021424v28c1a7dbgbaaf67ac12ca9526@mail.gmail.com> In-Reply-To: <39e6f6c70901021424v28c1a7dbgbaaf67ac12ca9526@mail.gmail.com> 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 Content-Length: 1504 Lines: 45 >> >> Just for curiosity. Why do you need such a binary tracing? >> Do you need it because a string output is really too slow for your needs? Hi, Frederic Weisbecker, We have 1) lots of kinds events source(FUNCTION trace, TRACE_CTX, tracepoint, markers ...) 2) a generic and mature events log buffer - trace/ringbuffer.c 3) a generic and mature trace framework - trace/trace.c trace_ouput.c But we don't have a generic events log format, we record different events with different record formats: TRACE_FN, TRACE_CTX, TRACE_GRAPH_RET, TRACE_SPECIAL, ... We use different struct for recording different formats. Too many kinds different formats, so we need a generic events log format. This patch provide generic events log format. Actually, We can use: __ftrace_bprintk(0, "# %ld %ld %ld\n", arg1, arg2, arg3) instead of TRACE_SPECIAL. (maybe I should remove the "unsigned long ip" arg for __ftrace_bprintk() and trace_vbprintk(), users need know the call_addr, just use "%pS") And binary record is a little slower than string output. Lai. Arnaldo Carvalho de Melo wrote: > > warning: I haven't looked at the patch details > > But I would love to use something like this to provide the exact > contents the userspace blktrace utilities want. > -- 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/