From: bugzilla-daemon@bugzilla.kernel.org
To: cpufreq@vger.kernel.org
Subject: [Bug 84851] New: CPU scaled down to 600 MHz even under load
Date: Sat, 20 Sep 2014 16:25:32 +0000 [thread overview]
Message-ID: <bug-84851-12968@https.bugzilla.kernel.org/> (raw)
https://bugzilla.kernel.org/show_bug.cgi?id=84851
Bug ID: 84851
Summary: CPU scaled down to 600 MHz even under load
Product: Power Management
Version: 2.5
Kernel Version: Tested at the moment with 3.17-rc5
Hardware: All
OS: Linux
Tree: Mainline
Status: NEW
Severity: normal
Priority: P1
Component: cpufreq
Assignee: cpufreq@vger.kernel.org
Reporter: bgamari@gmail.com
Regression: No
My Dell Latitude E7440 seems to occassionally enter periods where the
CPU clockrate of all cores (as shown by cpupower and powertop) is stuck in the
few-hundred-MHz range even under load. Often this is around 600 MHz.
At the moment I'm running 3.17-rc5 although I believe I have observed
similar behavior even under older kernels. I'm afraid I don't have a
reliable technique for reproducing the issue although it may be correlated with
S3 suspend. Various
If under load for long enough (several minutes) it seems it will eventually
clock back up to 2.0GHz. However, if I then kill the load it will clock back
down to 600MHz (as expected) and remain there until again subjected to
prolonged load.
I've attached a tarball with output from the various performance monitoring
tools (cpupower and turbostat) for several sets of conditions,
* while the machine is idle (v3.15-rc5-idle)
* while the machine is under load (provided by stress -c4) and clocked at
around 600 MHz (v3.15-rc5-loaded)
* after the machine has been load for roughly 3.5 minutes and has finally
clocked up to 2 GHz. Oddly it doesn't make it above 2.0GHz despite
cpuinfo_max_freq being 2.9GHz. (v3.15-rc5-loaded2)
Looking through sysfs I found the following a bit odd,
$ for i in /sys/devices/system/cpu/cpu0/cpufreq/*; do echo $i $(sudo cat $i);
done
cpufreq/affected_cpus 0
cpufreq/cpuinfo_cur_freq 628906
cpufreq/cpuinfo_max_freq 2900000
cpufreq/cpuinfo_min_freq 800000
cpufreq/cpuinfo_transition_latency 4294967295
cpufreq/related_cpus 0
cpufreq/scaling_available_governors performance powersave
cpufreq/scaling_driver intel_pstate
cpufreq/scaling_governor powersave
cpufreq/scaling_max_freq 2900000
cpufreq/scaling_min_freq 800000
cpufreq/scaling_setspeed <unsupported>
Note the peculiar value of cpuinfo_transition_latency. Seems just a tad long.
--
You are receiving this mail because:
You are the assignee for the bug.
next reply other threads:[~2014-09-20 16:25 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-20 16:25 bugzilla-daemon [this message]
2014-09-22 2:08 ` [Bug 84851] CPU scaled down to 600 MHz even under load bugzilla-daemon
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=bug-84851-12968@https.bugzilla.kernel.org/ \
--to=bugzilla-daemon@bugzilla.kernel.org \
--cc=cpufreq@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).