From mboxrd@z Thu Jan 1 00:00:00 1970
From: bugme-daemon@bugzilla.kernel.org
Subject: [Bug 9729] ondemand cpufreq governor doesn't see when
kcryptd/dm-crypt is busy
Date: Fri, 18 Jan 2008 14:42:43 -0800 (PST)
Message-ID: <20080118224243.DE720108069@picon.linux-foundation.org>
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http://bugzilla.kernel.org/show_bug.cgi?id=9729
tch@wpkg.org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|REOPENED |REJECTED
Resolution| |INVALID
------- Comment #3 from tch@wpkg.org 2008-01-18 14:42 -------
This indeed must be some kind of dm-crypt/kcryptd "feature" and/or some
confusion on how to read CPU usage.
While reading from that dm-crypt device, the following CPU usage was shown (the
numbers are consistent across a few tests):
187 MHz -> ~75% system CPU time in top
375 MHz -> ~66% system CPU time in top
562 MHz -> ~94% system CPU time in top
750 MHz -> ~85% system CPU time in top
937 MHz -> ~85% system CPU time in top
1125 MHz -> ~83% system CPU time in top
1312 MHz -> ~70% system CPU time in top
1500 MHz -> ~70% system CPU time in top
Looks like dm-crypt won't eat the whole CPU power for some reason.
With default 80 as up_threshold for "ondemand" governor, no wonder the
frequency didn't scale up.
So a "fix" for this bug is a matter of lowering up_threshold.
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