From: Rolf Fokkens <rolf@rolffokkens.nl>
To: Kent Overstreet <kmo@daterainc.com>
Cc: linux-bcache@vger.kernel.org
Subject: Re: bcache_writebac task 100% CPU
Date: Tue, 20 May 2014 21:38:35 +0200 [thread overview]
Message-ID: <537BAF3B.2020607@rolffokkens.nl> (raw)
In-Reply-To: <20140519165550.GD2276@kmo>
On 05/19/2014 06:55 PM, Kent Overstreet wrote:
> ...Changing it back to 25% doesn't do anything? _that_ is odd...
>
> Can you send me the output of writeback_rate_debug? Check it once before you've
> done anything, when things are working normally (after a fresh boot when
> writeback_percent is nonzero, probably), then grab it again after you've set
> writeback_percent to 0 and then back to 25, when it's still spinning.
I collected the requested data by logging both writeback_percent and
writeback_rate_debug every second. Every second also the cumulative CPU
usage of the bcache_writebac task is logged (as shown by ps -efw),
showing that the task is burning CPU cycles.
Both the collecting script and the log file can be found here:
https://bugzilla.kernel.org/show_bug.cgi?id=76391
> Also, what kernel are you running?
As mentioned before, the kernel is Fedora kernel
kernel-3.14.4-200.fc20.x86_64
prev parent reply other threads:[~2014-05-20 19:38 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-18 8:23 bcache_writebac task 100% CPU Rolf Fokkens
2014-05-19 16:55 ` Kent Overstreet
2014-05-19 18:01 ` Rolf Fokkens
2014-05-20 19:38 ` Rolf Fokkens [this message]
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