From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752338Ab1ARPuN (ORCPT ); Tue, 18 Jan 2011 10:50:13 -0500 Received: from mx1.redhat.com ([209.132.183.28]:62727 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751781Ab1ARPuM (ORCPT ); Tue, 18 Jan 2011 10:50:12 -0500 From: Jeff Moyer To: Tao Ma Cc: linux-kernel@vger.kernel.org, Jens Axboe , Steven Rostedt , Frederic Weisbecker Subject: Re: [PATCH] blktrace: Don't output messages if the user sets some action mask. References: <1295333017-5659-1-git-send-email-tm@tao.ma> X-PGP-KeyID: 1F78E1B4 X-PGP-CertKey: F6FE 280D 8293 F72C 65FD 5A58 1FF8 A7CA 1F78 E1B4 X-PCLoadLetter: What the f**k does that mean? Date: Tue, 18 Jan 2011 10:50:01 -0500 In-Reply-To: <1295333017-5659-1-git-send-email-tm@tao.ma> (Tao Ma's message of "Tue, 18 Jan 2011 14:43:37 +0800") Message-ID: User-Agent: Gnus/5.110011 (No Gnus v0.11) Emacs/23.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Tao Ma writes: > From: Tao Ma > > Now if we enable blktrace, cfq has too many messages output to the > trace buffer. It is fine if we don't specify any action mask. > But if I do like this: > blktrace /dev/sdb -a issue -a complete -o - | blkparse -i - > I only want to see 'D' and 'C', while with the following command > dd if=/mnt/ocfs2/test of=/dev/null bs=4k count=1 iflag=direct > > I will get(with a 2.6.37 vanilla kernel): > 8,16 0 0 0.000000000 0 m N cfq3805 alloced > 8,16 0 0 0.000004126 0 m N cfq3805 insert_request > 8,16 0 0 0.000004884 0 m N cfq3805 add_to_rr > 8,16 0 0 0.000008417 0 m N cfq workload slice:300 > 8,16 0 0 0.000009557 0 m N cfq3805 set_active wl_prio:0 wl_type:2 > 8,16 0 0 0.000010640 0 m N cfq3805 fifo= (null) > 8,16 0 0 0.000011193 0 m N cfq3805 dispatch_insert > 8,16 0 0 0.000012221 0 m N cfq3805 dispatched a request > 8,16 0 0 0.000012802 0 m N cfq3805 activate rq, drv=1 > 8,16 0 1 0.000013181 3805 D R 114759 + 8 [dd] > 8,16 0 2 0.000164244 0 C R 114759 + 8 [0] > 8,16 0 0 0.000167997 0 m N cfq3805 complete rqnoidle 0 > 8,16 0 0 0.000168782 0 m N cfq3805 set_slice=100 > 8,16 0 0 0.000169874 0 m N cfq3805 arm_idle: 8 group_idle: 0 > 8,16 0 0 0.000170189 0 m N cfq schedule dispatch > 8,16 0 0 0.000397938 0 m N cfq3805 slice expired t=0 > 8,16 0 0 0.000399763 0 m N cfq3805 sl_used=1 disp=1 charge=1 iops=0 sect=8 > 8,16 0 0 0.000400227 0 m N cfq3805 del_from_rr > 8,16 0 0 0.000400882 0 m N cfq3805 put_queue > > See, there are 19 lines while I only need 2. I don't think it is > appropriate for a user. > > So this patch will disable any messages if the user specify what he want to > see. Now the output for the same command will look like: > 8,16 0 1 0.000000000 4908 D R 114759 + 8 [dd] > 8,16 0 2 0.000146827 0 C R 114759 + 8 [0] > > Yes, it is what I want to see. > > Cc: Jens Axboe > Cc: Steven Rostedt > Cc: Frederic Weisbecker > Signed-off-by: Tao Ma > --- > kernel/trace/blktrace.c | 8 ++++++++ > 1 files changed, 8 insertions(+), 0 deletions(-) > > diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c > index 153562d..8219ffa 100644 > --- a/kernel/trace/blktrace.c > +++ b/kernel/trace/blktrace.c > @@ -138,6 +138,14 @@ void __trace_note_message(struct blk_trace *bt, const char *fmt, ...) > !blk_tracer_enabled)) > return; > > + /* > + * If the user does specify some action masks, don't send any note > + * message to the trace so that it won't pollute what the user really > + * want to see. > + */ > + if (bt->act_mask != (u16) -1) > + return; > + I think you want to check for the BLK_TC_NOTIFY bit. Cheers, Jeff