Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754215Ab0DOPFz (ORCPT ); Thu, 15 Apr 2010 11:05:55 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.125]:57577 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753779Ab0DOPFy (ORCPT ); Thu, 15 Apr 2010 11:05:54 -0400 X-Authority-Analysis: v=1.1 cv=wzQuF8Yqs4IO6CYUtTy28yZyBjSHZbbofww7aEg0rsQ= c=1 sm=0 a=IkcTkHD0fZMA:10 a=gMqfjgEr1zLu/65IO0LwxA==:17 a=D19gQVrFAAAA:8 a=PpKaerNTvt2m38JixWMA:9 a=DpBJh3Lxepyrfg9d6BrlnNs7YpgA:4 a=QEXdDO2ut3YA:10 a=gMqfjgEr1zLu/65IO0LwxA==:117 X-Cloudmark-Score: 0 X-Originating-IP: 74.67.89.75 Subject: Re: sched_clock - microblaze From: Steven Rostedt To: michal.simek@petalogix.com Cc: Thomas Gleixner , LKML , Wu Zhangjin In-Reply-To: <4BC728DD.5020404@petalogix.com> References: <4BC728DD.5020404@petalogix.com> Content-Type: text/plain; charset="UTF-8" Date: Thu, 15 Apr 2010 11:04:48 -0400 Message-ID: <1271343888.1880.1.camel@localhost> Mime-Version: 1.0 X-Mailer: Evolution 2.28.3 (2.28.3-1.fc12) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2040 Lines: 54 On Thu, 2010-04-15 at 16:55 +0200, Michal Simek wrote: > Hi Thomas and Steven, > > I would like to improve time measuring for ftrace (Log below) > > I looked at http://lkml.org/lkml/2009/11/16/181 > where Thomas suggested to create sched_clock() function. > I used the same solution as Wu proposed but it is not nice. > > Is unimplemented sched_clock the reason why ftrace not show fine grain time? Yeah, sched_clock is used by ftrace for timings, so if it only returns jiffies, then that will, unfortunately, be the resolution of the tracer. I've been told that if you make a higher resolution timer for sched clock, it will improve the scheduling in CFS. -- Steve > > Or is there any other thing which is wrong? > > Thanks, > Michal > > > > Dumping ftrace buffer: > --------------------------------- > 0) ! 10000.00 us | } > 0) <========== | > 0) ! 10000.00 us | } > 0) ! 10000.00 us | } > 0) 0.000 us | get_seconds(); > 0) 0.000 us | tcp_rcv_rtt_update(); > 0) 0.000 us | tcp_ack(); > 0) 0.000 us | tcp_rcv_rtt_update(); > 0) 0.000 us | tcp_urg(); > 0) | tcp_data_queue() { > 0) 0.000 us | __sk_mem_schedule(); > 0) 0.000 us | tcp_event_data_recv(); > 0) 0.000 us | sock_def_readable(); > 0) 0.000 us | } > 0) 0.000 us | tcp_check_space(); > 0) | __tcp_ack_snd_check() { > > -- 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/