Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756904AbYLQEQm (ORCPT ); Tue, 16 Dec 2008 23:16:42 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750945AbYLQEQc (ORCPT ); Tue, 16 Dec 2008 23:16:32 -0500 Received: from tomts13-srv.bellnexxia.net ([209.226.175.34]:59683 "EHLO tomts13-srv.bellnexxia.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750916AbYLQEQb (ORCPT ); Tue, 16 Dec 2008 23:16:31 -0500 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: Av8EAKwGSElMROB9/2dsb2JhbACBbLp4V5E+gn8 Date: Tue, 16 Dec 2008 23:16:28 -0500 From: Mathieu Desnoyers To: Ingo Molnar Cc: Andrew Morton , linux-kernel@vger.kernel.org, Steven Rostedt , ltt-dev@lists.casi.polymtl.ca, Linus Torvalds , Pekka Enberg , Thomas Gleixner Subject: Re: [ltt-dev] [PATCH] Simple LTTng userspace events through debugfs Message-ID: <20081217041628.GA5409@Krystal> References: <20081215231040.GA5936@Krystal> <20081216194201.GE843@elte.hu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline In-Reply-To: <20081216194201.GE843@elte.hu> X-Editor: vi X-Info: http://krystal.dyndns.org:8080 X-Operating-System: Linux/2.6.21.3-grsec (i686) X-Uptime: 23:12:00 up 30 days, 4:52, 2 users, load average: 4.68, 4.81, 3.36 User-Agent: Mutt/1.5.16 (2007-06-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Ingo Molnar (mingo@elte.hu) wrote: > > * Mathieu Desnoyers wrote: > > > Hi, > > > > I looked at kmemtrace and noticed that the presence of a debugfs > > "marker" file, which lets userspace write events into the trace buffers. > > > > So I just did the same with a > > > > /debugfs/ltt/write_event > > you mean similar to ftrace's /debug/tracing/trace_marker ? ;-) > Quite similar, yes :) Looking at tracing_mark_write(), I am wondering if the fact that it returns a count including the added \n is an expected side effect ? A write() returning a count larger than the number of bytes written seems to be a bit unexpected... But if we remove the \n from the count, then the case where one write \0 into the event content would end up doing an endless loop. Mathieu > Ingo > > _______________________________________________ > ltt-dev mailing list > ltt-dev@lists.casi.polymtl.ca > http://lists.casi.polymtl.ca/cgi-bin/mailman/listinfo/ltt-dev > -- Mathieu Desnoyers OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68 -- 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/