From: Christoph Hellwig <hch@infradead.org>
To: Jeff Moyer <jmoyer@redhat.com>
Cc: jens.axboe@fusionio.com, linux-kernel@vger.kernel.org
Subject: Re: blk_classic tracing horribly broken
Date: Thu, 22 Sep 2011 14:12:16 -0400 [thread overview]
Message-ID: <20110922181216.GA13772@infradead.org> (raw)
In-Reply-To: <x491uv8h348.fsf@segfault.boston.devel.redhat.com>
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.
next prev parent reply other threads:[~2011-09-22 18:12 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-22 17:57 blk_classic tracing horribly broken Jeff Moyer
2011-09-22 18:12 ` Christoph Hellwig [this message]
2011-09-22 18:32 ` Jeff Moyer
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