* blk_classic tracing horribly broken
@ 2011-09-22 17:57 Jeff Moyer
2011-09-22 18:12 ` Christoph Hellwig
0 siblings, 1 reply; 3+ messages in thread
From: Jeff Moyer @ 2011-09-22 17:57 UTC (permalink / raw)
To: jens.axboe; +Cc: linux-kernel
Hi,
I've stared at the code for a while, and I've come up empty. Would
anyone care to take a stab at fixing this?
To reproduce:
mount -t debugfs none /sys/kernel/debug
cd /sys/kernel/debug/tracing
echo blk > current_tracer
echo 1 > events/block/enable
echo 1 > options/blk_classic
echo 1 > tracing_on
dd if=/dev/<device> of=/dev/null bs=1M count=1 iflag=direct
cat trace
This is what I see:
# tracer: blk
#
# DEV CPU TIMESTAMP PID ACT FLG
# | | | | | |
Unknown action 52
Unknown action 52
Unknown action bce
Unknown action 52
Unknown action 52
Unknown action 52
Unknown action 52
Unknown action 52
Unknown action 52
Unknown action 0
Unknown action 0
Unknown action 0
Unknown action 0
Unknown action 0
Unknown action 0
Unknown action 0
Unknown action 0
Unknown action 0
Unknown action 0
Unknown action 0
Unknown action 0
Unknown action 0
0,0 2 110.941937315 2584 F R [pgrep]
Unknown action 52
Unknown action 52
Unknown action 231
Unknown action 0
Unknown action 0
Unknown action 0
Unknown action 0
0,0 0 110.949383287 2584 F R [pgrep]
Unknown action 52
Unknown action 52
Unknown action 7fd1
Unknown action 0
Unknown action 0
Unknown action 0
Unknown action 0
0,0 3 110.984565328 2581 F R [ps]
Unknown action 52
Unknown action 52
Unknown action 5ad1
Unknown action 0
Unknown action 0
Unknown action 0
Unknown action 0
0,0 3 111.003843579 2581 F R [ps]
Unknown action 52
Unknown action 52
Unknown action 7551
Unknown action 0
Unknown action 0
Unknown action 0
Unknown action 0
Cheers,
Jeff
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: blk_classic tracing horribly broken
2011-09-22 17:57 blk_classic tracing horribly broken Jeff Moyer
@ 2011-09-22 18:12 ` Christoph Hellwig
2011-09-22 18:32 ` Jeff Moyer
0 siblings, 1 reply; 3+ messages in thread
From: Christoph Hellwig @ 2011-09-22 18:12 UTC (permalink / raw)
To: Jeff Moyer; +Cc: jens.axboe, linux-kernel
On Thu, Sep 22, 2011 at 01:57:11PM -0400, Jeff Moyer wrote:
> Hi,
>
> I've stared at the code for a while, and I've come up empty. Would
> anyone care to take a stab at fixing this?
>
> To reproduce:
>
> mount -t debugfs none /sys/kernel/debug
> cd /sys/kernel/debug/tracing
> echo blk > current_tracer
> echo 1 > events/block/enable
> echo 1 > options/blk_classic
> echo 1 > tracing_on
>
> dd if=/dev/<device> of=/dev/null bs=1M count=1 iflag=direct
> cat trace
Why are you using this interface anyway? We actually had planned to
drop it long time ago, but for some reason that never happened.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: blk_classic tracing horribly broken
2011-09-22 18:12 ` Christoph Hellwig
@ 2011-09-22 18:32 ` Jeff Moyer
0 siblings, 0 replies; 3+ messages in thread
From: Jeff Moyer @ 2011-09-22 18:32 UTC (permalink / raw)
To: Christoph Hellwig; +Cc: jens.axboe, linux-kernel
Christoph Hellwig <hch@infradead.org> writes:
> On Thu, Sep 22, 2011 at 01:57:11PM -0400, Jeff Moyer wrote:
>> Hi,
>>
>> I've stared at the code for a while, and I've come up empty. Would
>> anyone care to take a stab at fixing this?
>>
>> To reproduce:
>>
>> mount -t debugfs none /sys/kernel/debug
>> cd /sys/kernel/debug/tracing
>> echo blk > current_tracer
>> echo 1 > events/block/enable
>> echo 1 > options/blk_classic
>> echo 1 > tracing_on
>>
>> dd if=/dev/<device> of=/dev/null bs=1M count=1 iflag=direct
>> cat trace
>
> Why are you using this interface anyway? We actually had planned to
> drop it long time ago, but for some reason that never happened.
I was using it when testing the flush+fua reporting in blktrace, to be
sure we didn't break it. Since it was already broken, I didn't have to
worry, but I put it on my todo list to investigate why. Dropping broken
code is fine with me (given that there are two alternatives to use).
Cheers,
Jeff
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2011-09-22 18:32 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2011-09-22 17:57 blk_classic tracing horribly broken Jeff Moyer
2011-09-22 18:12 ` Christoph Hellwig
2011-09-22 18:32 ` Jeff Moyer
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