[Dell Latitude E6520] After suspend, machine very slow with ondemand governor

[Laurent Bonnaud]

After several suspend/resume cycles and several days of uptime, using the ondemand governor the system is very slow to answer some inputs. The text output pauses for several seconds while I am typing this text. Trying to scroll a firefox window takes several seconds. Switching tabs in firefox takes several seconds:
cat /sys/devices/system/cpu/c*/cpufreq/scaling_governor
ondemand
ondemand
ondemand
ondemand

WORKAROUND: Setting the governor to "performance" fixes this problem.

ProblemType: Bug
DistroRelease: Ubuntu 13.10
Package: linux-image-3.11.0-15-generic 3.11.0-15.23
ProcVersionSignature: Ubuntu 3.11.0-15.23-generic 3.11.10
Uname: Linux 3.11.0-15-generic x86_64
NonfreeKernelModules: wl
ApportVersion: 2.12.5-0ubuntu2.2
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: bonnaudl 2373 F.... pulseaudio
Date: Thu Dec 26 18:17:23 2013
EcryptfsInUse: Yes
HibernationDevice: RESUME=UUID=cf81afe7-8427-45fa-9149-c11d060a5a26
InstallationDate: Installed on 2013-04-27 (243 days ago)
InstallationMedia: Ubuntu 13.04 "Raring Ringtail" - Release amd64 (20130424)
MachineType: Dell Inc. Latitude E6520
MarkForUpload: True
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.11.0-15-generic root=UUID=749a9901-bdd3-4b5f-b80e-69414667e058 ro quiet splash vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-3.11.0-15-generic N/A
 linux-backports-modules-3.11.0-15-generic N/A
 linux-firmware 1.116
SourcePackage: linux
UpgradeStatus: Upgraded to saucy on 2013-10-01 (86 days ago)
dmi.bios.date: 02/28/2012
dmi.bios.vendor: Dell Inc.
dmi.bios.version: A12
dmi.board.name: 0NVF5K
dmi.board.vendor: Dell Inc.
dmi.board.version: A01
dmi.chassis.type: 9
dmi.chassis.vendor: Dell Inc.
dmi.modalias: dmi:bvnDellInc.:bvrA12:bd02/28/2012:svnDellInc.:pnLatitudeE6520:pvr01:rvnDellInc.:rn0NVF5K:rvrA01:cvnDellInc.:ct9:cvr:
dmi.product.name: Latitude E6520
dmi.product.version: 01
dmi.sys.vendor: Dell Inc.

[Laurent Bonnaud (laurent-bonnaud)]

Running frequency_governors_test sheds some light on this bug because it exposes this error:

ERROR On demand performance vs maximum of 380.0% is not within 10.0% margin

# /usr/lib/checkbox/bin/frequency_governors_test
2013-12-26 18:15:54 INFO System Capabilites:
2013-12-26 18:15:54 INFO -------------------------------------------------
2013-12-26 18:15:54 INFO System has 4 cpus
2013-12-26 18:15:54 INFO Supported CPU Frequencies:
2013-12-26 18:15:54 INFO 2801 MHz
2013-12-26 18:15:54 INFO 2800 MHz
2013-12-26 18:15:54 INFO 2600 MHz
2013-12-26 18:15:54 INFO 2400 MHz
2013-12-26 18:15:54 INFO 2200 MHz
2013-12-26 18:15:54 INFO 2000 MHz
2013-12-26 18:15:54 INFO 1800 MHz
2013-12-26 18:15:54 INFO 1600 MHz
2013-12-26 18:15:54 INFO 1400 MHz
2013-12-26 18:15:54 INFO 1200 MHz
2013-12-26 18:15:54 INFO 1000 MHz
2013-12-26 18:15:54 INFO 800 MHz
2013-12-26 18:15:54 INFO Supported Governors:
2013-12-26 18:15:54 INFO conservative
2013-12-26 18:15:54 INFO ondemand
2013-12-26 18:15:54 INFO userspace
2013-12-26 18:15:54 INFO powersave
2013-12-26 18:15:54 INFO performance
2013-12-26 18:15:54 INFO Current governors:
2013-12-26 18:15:54 INFO cpu0: conservative
2013-12-26 18:15:54 INFO cpu1: conservative
2013-12-26 18:15:54 INFO cpu2: conservative
2013-12-26 18:15:54 INFO cpu3: conservative
2013-12-26 18:15:54 INFO Beginning Frequency Governors Testing
2013-12-26 18:15:54 INFO Userspace Governor Test:
2013-12-26 18:15:54 INFO -------------------------------------------------
2013-12-26 18:15:54 INFO Setting governor to userspace
2013-12-26 18:16:25 INFO Setting CPU frequency to 800 MHz
2013-12-26 18:16:25 INFO Running CPU load test...
2013-12-26 18:16:25 INFO pid 4613's current affinity list: 0-3
2013-12-26 18:16:25 INFO pid 4613's new affinity list: 0
2013-12-26 18:16:25 INFO Minimum frequency load test time: 0.23
2013-12-26 18:16:25 INFO Setting CPU frequency to 2801 MHz
2013-12-26 18:16:25 INFO Running CPU load test...
2013-12-26 18:16:25 INFO pid 4613's current affinity list: 0
2013-12-26 18:16:25 INFO pid 4613's new affinity list: 0
2013-12-26 18:16:25 INFO Maximum frequency load test time: 0.05
2013-12-26 18:16:25 INFO Found ida flag, increasing expected speedup by 8.0%
2013-12-26 18:16:25 INFO CPU Frequency Speed Up: 3.81
2013-12-26 18:16:25 INFO Measured Speed Up: 4.60
2013-12-26 18:16:25 INFO Percentage Difference 20.9%
2013-12-26 18:16:25 ERROR Measured speedup vs expected speedup is 20.9% and is not within 10.0% margin.
2013-12-26 18:16:25 INFO On Demand Governor Test:
2013-12-26 18:16:25 INFO -------------------------------------------------
2013-12-26 18:16:25 INFO Setting governor to ondemand
2013-12-26 18:16:25 INFO Waiting 5 seconds...
2013-12-26 18:16:30 INFO Done.
2013-12-26 18:16:30 INFO Running CPU load test...
2013-12-26 18:16:30 INFO pid 4613's current affinity list: 0
2013-12-26 18:16:30 INFO pid 4613's new affinity list: 0
2013-12-26 18:16:31 IN...

[Laurent Bonnaud (laurent-bonnaud)]

This bug is similar to bug #326149 but I preferred to report a new one because this other bug:
 - is closed
 - concerns a very old kernel
 - concerns a very different processor

[Brad Figg (brad-figg)]

This change was made by a bot.

[Laurent Bonnaud (laurent-bonnaud)]

I changed the bug description to state the difficulty of reproducing this bug.

[Laurent Bonnaud (laurent-bonnaud)]

Since my initial report I updated the BIOS of this laptop:

$ sudo dmidecode -s bios-version && sudo dmidecode -s bios-release-date
A19
11/14/2013

and today (after 8 days of uptime and perhaps 20 suspend/resume cycles) the bug reappeared:

# /usr/lib/checkbox/bin/frequency_governors_test
2014-01-23 12:09:52 INFO System Capabilites:
2014-01-23 12:09:52 INFO -------------------------------------------------
2014-01-23 12:09:52 INFO System has 4 cpus
2014-01-23 12:09:52 INFO Supported CPU Frequencies:
2014-01-23 12:09:52 INFO 2801 MHz
2014-01-23 12:09:52 INFO 2800 MHz
2014-01-23 12:09:52 INFO 2600 MHz
2014-01-23 12:09:52 INFO 2400 MHz
2014-01-23 12:09:52 INFO 2200 MHz
2014-01-23 12:09:52 INFO 2000 MHz
2014-01-23 12:09:52 INFO 1800 MHz
2014-01-23 12:09:52 INFO 1600 MHz
2014-01-23 12:09:52 INFO 1400 MHz
2014-01-23 12:09:52 INFO 1200 MHz
2014-01-23 12:09:52 INFO 1000 MHz
2014-01-23 12:09:52 INFO 800 MHz
2014-01-23 12:09:52 INFO Supported Governors:
2014-01-23 12:09:52 INFO conservative
2014-01-23 12:09:52 INFO ondemand
2014-01-23 12:09:52 INFO userspace
2014-01-23 12:09:52 INFO powersave
2014-01-23 12:09:52 INFO performance
2014-01-23 12:09:52 INFO Current governors:
2014-01-23 12:09:52 INFO cpu0: ondemand
2014-01-23 12:09:52 INFO cpu1: ondemand
2014-01-23 12:09:52 INFO cpu2: ondemand
2014-01-23 12:09:52 INFO cpu3: ondemand
2014-01-23 12:09:52 INFO Beginning Frequency Governors Testing
2014-01-23 12:09:52 INFO Userspace Governor Test:
2014-01-23 12:09:52 INFO -------------------------------------------------
2014-01-23 12:09:52 INFO Setting governor to userspace
2014-01-23 12:10:22 INFO Setting CPU frequency to 800 MHz
2014-01-23 12:10:22 INFO Running CPU load test...
2014-01-23 12:10:22 INFO pid 4285's current affinity list: 0-3
2014-01-23 12:10:22 INFO pid 4285's new affinity list: 0
2014-01-23 12:10:23 INFO Minimum frequency load test time: 0.25
2014-01-23 12:10:23 INFO Setting CPU frequency to 2801 MHz
2014-01-23 12:10:23 INFO Running CPU load test...
2014-01-23 12:10:23 INFO pid 4285's current affinity list: 0
2014-01-23 12:10:23 INFO pid 4285's new affinity list: 0
2014-01-23 12:10:23 INFO Maximum frequency load test time: 0.05
2014-01-23 12:10:23 INFO Found ida flag, increasing expected speedup by 8.0%
2014-01-23 12:10:23 INFO CPU Frequency Speed Up: 3.81
2014-01-23 12:10:23 INFO Measured Speed Up: 5.00
2014-01-23 12:10:23 INFO Percentage Difference 31.4%
2014-01-23 12:10:23 ERROR Measured speedup vs expected speedup is 31.4% and is not within 10.0% margin.
2014-01-23 12:10:23 INFO On Demand Governor Test:
2014-01-23 12:10:23 INFO -------------------------------------------------
2014-01-23 12:10:23 INFO Setting governor to ondemand
2014-01-23 12:10:23 INFO Waiting 5 seconds...
2014-01-23 12:10:28 INFO Done.
2014-01-23 12:10:28 INFO Running CPU load test...
2014-01-23 12:10:28 INFO pid 4285's current affinity list: 0
2014-01-23 12:10:28 INFO pi...

[penalvch (penalvch)]

Laurent Bonnaud, thank you for updating your BIOS. Could you please confirm this issue exists with the latest development release of Ubuntu? ISO images are available from http://cdimage.ubuntu.com/daily-live/current/ . If the issue remains, please just make a comment to this.

If reproducible, could you also please test the latest upstream kernel available (not the daily folder) following https://wiki.ubuntu.com/KernelMainlineBuilds ? It will allow additional upstream developers to examine the issue. Once you've tested the upstream kernel, please comment on which kernel version specifically you tested. If this bug is fixed in the mainline kernel, please add the following tags:
kernel-fixed-upstream
kernel-fixed-upstream-VERSION-NUMBER

where VERSION-NUMBER is the version number of the kernel you tested. For example:
kernel-fixed-upstream-3.13

This can be done by clicking on the yellow circle with a black pencil icon next to the word Tags located at the bottom of the bug description. As well, please remove the tag:
needs-upstream-testing

If the mainline kernel does not fix this bug, please add the following tags:
kernel-bug-exists-upstream
kernel-bug-exists-upstream-VERSION-NUMBER

As well, please remove the tag:
needs-upstream-testing

Once testing of the upstream kernel is complete, please mark this bug's Status as Confirmed. Please let us know your results. Thank you for your understanding.

[Allan Crooks (amcone)]

Having this problem as well with my Dell Latitude E7440 - switching to performance seemed to help as well (thanks Laurent!)

The slowdown doesn't always happen, but it does appear to happen after sometimes resuming from standby. I've not known whether to blame it on the DE I was using (Cinnamon) or some other component.

[Laurent Bonnaud (laurent-bonnaud)]

> Could you please confirm this issue exists with the latest development release of Ubuntu?

I am using this system as my main computing platform and therefore I cannot do tests that span several days.

> It will allow additional upstream developers to examine the issue.

Unfortunately my kernel is "tainted" (because it has a Wifi adapter that requires a non-free driver) and therefore I am afraid that upstream kernel developers will not consider this bug. I am in the process of replacing this Wifi adapter but it will take time...

[Laurent Bonnaud (laurent-bonnaud)]

> The slowdown doesn't always happen, but it does appear to happen after sometimes resuming from standby.

In my case I suspect that the problem might be caused by a non-compatible power adapter (I am using several ones). Since I reported the problem I changed this power adapter and did not see the problem again. Do you use a non-Dell or non-compatible Dell power adapter ?

> I've not known whether to blame it on the DE I was using (Cinnamon) or some other component.

The DE should have nothing to do with it. This is clearly a kernel/BIOS problem.

[Allan Crooks (amcone)]

> Since I reported the problem I changed this power adapter and did not see the problem again. Do you use a non-Dell or non-compatible Dell power adapter ?

I've always been using the standard Dell power adapter that came with the laptop. The last time it happened, the laptop was running from battery. The problem does seem to be a lot less frequent, but when it does happen, it seems the CPU is pegged at 756 MHz (a number in the 700's anyway, I can't recall the precise figure at the moment.) I've been using an applet to keep an eye on the frequency.

[penalvch (penalvch)]

Allan Crooks, thank you for your comment. So your hardware and problem may be tracked, could you please file a new report with Ubuntu by executing the following in a terminal while booted into a Ubuntu repository kernel (not a mainline one) via:
ubuntu-bug linux

For more on this, please read the official Ubuntu documentation:
Ubuntu Bug Control and Ubuntu Bug Squad: https://wiki.ubuntu.com/Bugs/BestPractices#X.2BAC8-Reporting.Focus_on_One_Issue
Ubuntu Kernel Team: https://wiki.ubuntu.com/KernelTeam/KernelTeamBugPolicies#Filing_Kernel_Bug_reports
Ubuntu Community: https://help.ubuntu.com/community/ReportingBugs#Bug_reporting_etiquette

When opening up the new report, please feel free to subscribe me to it.

Thank you for your understanding.

Helpful bug reporting tips:
https://wiki.ubuntu.com/ReportingBugs

[Laurent Bonnaud (laurent-bonnaud)]

I cannot reproduce the problem with trusty, therefore I am going to close this bug...

[Jeroen Claeys (jeroenclaeys)]

I'm still having this problem after updating to 14.10.

This issue exclusively arises if I suspend my laptop when connected to the power cord, then unplug it during suspend and wake it up on battery. It does not happen every time, maybe once in seven times.

The scaling_governor keeps all cores at "powersave". As soon as I replace that with "performance" through cpufreq-set the issue is solved.

[penalvch (penalvch)]

Jere, as this bug report is closed, this bug report is not scoped to you, your hardware, or your problem. So your hardware and problem may be tracked, could you please file a new report with Ubuntu by executing the following in a terminal while booted into the default Ubuntu kernel (not a mainline one) via:
ubuntu-bug linux

For more on this, please read the official Ubuntu documentation:
Ubuntu Bug Control and Ubuntu Bug Squad: https://wiki.ubuntu.com/Bugs/BestPractices#X.2BAC8-Reporting.Focus_on_One_Issue
Ubuntu Kernel Team: https://wiki.ubuntu.com/KernelTeam/KernelTeamBugPolicies#Filing_Kernel_Bug_reports
https://wiki.ubuntu.com/Kernel/Policies/DuplicateBugs
Ubuntu Community: https://help.ubuntu.com/community/ReportingBugs#Bug_reporting_etiquette

When opening up the new report, please feel free to subscribe me to it.

As well, please do not announce in this report you created a new bug report.

Thank you for your understanding.

Helpful bug reporting tips:
https://wiki.ubuntu.com/ReportingBugs