From: "Stephan Bärwolf" <stephan.baerwolf@tu-ilmenau.de>
To: linux-kernel@vger.kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Michael Buesch <mb@bu3sch.de>,
Chris Wilson <chris@chris-wilson.co.uk>,
Alex Deucher <alexdeucher@gmail.com>,
Dave Airlie <airlied@redhat.com>
Subject: responsiveness: newer kernels causing lagging and blocking
Date: Thu, 23 Feb 2012 17:30:41 +0100 [thread overview]
Message-ID: <4F4669B1.4020306@tu-ilmenau.de> (raw)
Under various conditions linux since 2.6.39-rc1 laggs and blocks enormously the whole system.
(For example while starting "winecfg" (on a thinkpad X220) and parallel moving the
mousecursor you can observe a periodic blocking for some seconds)
After bisecting a little while, commit "4819d2e4310796c4e9eef674499af9b9caf36b5a"
(" drm: Retry i2c transfer of EDID block after failure ") seems to be responsible.
Because function "drm_do_probe_ddc_edid" loops trying "i2c_transfer" it consumes a lot
of time during errors. Reverting or changing "retries" from 5 to 1 extremly minimizes the
problem to "not perceptible".
It seems the locking within "i2c_transfer" slows everything down.
So maybe it is possible to yield() before calling it?
regards Stephan
next reply other threads:[~2012-02-23 17:02 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-23 16:30 Stephan Bärwolf [this message]
2012-02-23 17:12 ` responsiveness: newer kernels causing lagging and blocking Linus Torvalds
2012-02-23 17:26 ` Stephan Bärwolf
2012-02-23 17:21 ` Chris Wilson
2012-02-23 17:29 ` Linus Torvalds
2012-02-23 17:31 ` Dave Airlie
2012-02-23 18:15 ` Linus Torvalds
2012-02-23 19:52 ` [PATCH] drm: Reduce the number of retries whilst reading EDIDs Chris Wilson
2012-02-23 20:15 ` Linus Torvalds
2012-02-23 20:36 ` Linus Torvalds
2012-02-23 21:36 ` Eugeni Dodonov
2012-02-23 21:40 ` Linus Torvalds
2012-02-24 15:17 ` Adam Jackson
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