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Message-Id: <1295333017-5659-1-git-send-email-tm@tao.ma> Date: Tue, 18 Jan 2011 14:43:37 +0800 From: Tao Ma <tm@....ma> To: linux-kernel@...r.kernel.org Cc: Jens Axboe <axboe@...nel.dk>, Steven Rostedt <rostedt@...dmis.org>, Frederic Weisbecker <fweisbec@...il.com> Subject: [PATCH] blktrace: Don't output messages if the user sets some action mask. From: Tao Ma <boyu.mt@...bao.com> 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 <axboe@...nel.dk> Cc: Steven Rostedt <rostedt@...dmis.org> Cc: Frederic Weisbecker <fweisbec@...il.com> Signed-off-by: Tao Ma <boyu.mt@...bao.com> --- 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; + local_irq_save(flags); buf = per_cpu_ptr(bt->msg_data, smp_processor_id()); va_start(args, fmt); -- 1.6.3.GIT -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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