From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756131Ab1EDWXh (ORCPT ); Wed, 4 May 2011 18:23:37 -0400 Received: from cantor.suse.de ([195.135.220.2]:54227 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753818Ab1EDWXg (ORCPT ); Wed, 4 May 2011 18:23:36 -0400 Date: Thu, 5 May 2011 00:23:33 +0200 From: Jan Kara To: Wu Fengguang Cc: Andrew Morton , Jan Kara , Dave Chinner , LKML , linux-fsdevel@vger.kernel.org Subject: Re: [PATCH 6/6] writeback: convert to relative older_than_this in trace events Message-ID: <20110504222333.GL6968@quack.suse.cz> References: <20110504091707.910929441@intel.com> <20110504091909.904141006@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110504091909.904141006@intel.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 04-05-11 17:17:13, Wu Fengguang wrote: > This is a format change that could break established scripts. > > But hopefully it's more human friendly to show the relative values like > "30000" (30s old) or "0" (all fresh ones) than long absolute jiffy > numbers. It's possibly more human friendly but probably also harder to handle in scripts. I especially don't like the fact that the number will be changing at different tracepoints - you'll then have to do some comparisons to find out whether just the timestamp has been changed or whether just the time passes by. It's not that hard to write a script doing absolute->relative conversion (since you have time stamps in the traces) for those cases where relative time is really what interests you. So do you have any particular usecase in mind for the relative value? Honza > > Note that the initial 30000 or 0 may increase over time as they are now > relative numbers. > > CC: Jan Kara > CC: Dave Chinner > Signed-off-by: Wu Fengguang > --- > include/trace/events/writeback.h | 11 ++++++----- > 1 file changed, 6 insertions(+), 5 deletions(-) > > --- linux-next.orig/include/trace/events/writeback.h 2011-05-04 16:09:59.000000000 +0800 > +++ linux-next/include/trace/events/writeback.h 2011-05-04 16:10:57.000000000 +0800 > @@ -115,7 +115,7 @@ DECLARE_EVENT_CLASS(wbc_class, > __field(int, for_reclaim) > __field(int, range_cyclic) > __field(int, more_io) > - __field(unsigned long, older_than_this) > + __field(int, older) > __field(long, range_start) > __field(long, range_end) > ), > @@ -130,14 +130,15 @@ DECLARE_EVENT_CLASS(wbc_class, > __entry->for_reclaim = wbc->for_reclaim; > __entry->range_cyclic = wbc->range_cyclic; > __entry->more_io = wbc->more_io; > - __entry->older_than_this = wbc->older_than_this ? > - *wbc->older_than_this : 0; > + __entry->older = wbc->older_than_this ? > + (jiffies - *wbc->older_than_this) * 1000 / HZ > + : -1; > __entry->range_start = (long)wbc->range_start; > __entry->range_end = (long)wbc->range_end; > ), > > TP_printk("bdi %s: towrt=%ld skip=%ld mode=%d kupd=%d " > - "bgrd=%d reclm=%d cyclic=%d more=%d older=0x%lx " > + "bgrd=%d reclm=%d cyclic=%d more=%d older=%d " > "start=0x%lx end=0x%lx", > __entry->name, > __entry->nr_to_write, > @@ -148,7 +149,7 @@ DECLARE_EVENT_CLASS(wbc_class, > __entry->for_reclaim, > __entry->range_cyclic, > __entry->more_io, > - __entry->older_than_this, > + __entry->older, > __entry->range_start, > __entry->range_end) > ) > > -- Jan Kara SUSE Labs, CR