Bug 680041
| Summary: | High CPU usage regardless latest kernel versions | ||||||||||||
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| Product: | [Fedora] Fedora | Reporter: | Krzysztof "Uosiu" Hajdamowicz <uosiumen> | ||||||||||
| Component: | kernel | Assignee: | John Feeney <jfeeney> | ||||||||||
| Status: | CLOSED NOTABUG | QA Contact: | Fedora Extras Quality Assurance <extras-qa> | ||||||||||
| Severity: | high | Docs Contact: | |||||||||||
| Priority: | unspecified | ||||||||||||
| Version: | 14 | CC: | bugzilla, gansalmon, itamar, jfeeney, jonathan, kernel-maint, madhu.chinakonda | ||||||||||
| Target Milestone: | --- | ||||||||||||
| Target Release: | --- | ||||||||||||
| Hardware: | x86_64 | ||||||||||||
| OS: | Linux | ||||||||||||
| Whiteboard: | |||||||||||||
| Fixed In Version: | Doc Type: | Bug Fix | |||||||||||
| Doc Text: | Story Points: | --- | |||||||||||
| Clone Of: | 635813 | Environment: | |||||||||||
| Last Closed: | 2011-02-28 23:11:20 UTC | Type: | --- | ||||||||||
| Regression: | --- | Mount Type: | --- | ||||||||||
| Documentation: | --- | CRM: | |||||||||||
| Verified Versions: | Category: | --- | |||||||||||
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |||||||||||
| Cloudforms Team: | --- | Target Upstream Version: | |||||||||||
| Embargoed: | |||||||||||||
| Attachments: |
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Description
Krzysztof "Uosiu" Hajdamowicz
2011-02-24 07:39:40 UTC
Created attachment 480678 [details]
/boot/grub/menu.lst
Please repeat using an idle system. You've got ~300 wakeups a second from your web browser and java, which is going to be responsible for a lot of the rebalancing. *** Bug 664027 has been marked as a duplicate of this bug. *** Also, please make sure that there are no wakeups from i8042 (ie, don't touch the keyboard or touchpad) Created attachment 481465 [details]
Powertop on idle Laptop
23:54 [ root @ samhain ] /opt ROOTMODE> uname -a
Linux samhain 2.6.35.11-83.fc14.x86_64 #1 SMP Mon Feb 7 07:06:44 UTC 2011 x86_64 x86_64 x86_64 GNU/Linux
Completely idle
Created attachment 481467 [details]
Archive screenshot from powertop - Dec 5, 2009
I can't remember Kernel version and Fedora version, but this screenshot was taken on December 5th 2009 with up-do-date system and packages. Unbeaten power consumption score.
You've got activity from evince, nautilus, something's hitting the disk and X is asking for interrupts. Otherwise you'd have pretty identical results, so I don't see any sign of a kernel bug here. You may want to file bugs against evince, nautilus, knotify and psi. Regardless of that activity, Load Balancing Tick causes most CPU wakeups. It's job is causing more job for itself. Starting boinc-client with milestone RSA bruteforcing and WorldCommunityGrid - Fight AIDS@Home causes: 86,7% (1721,6) [kernel scheduler] Load balancing tick 2,2% ( 43,0) chromium-browse 1,8% ( 35,8) Xorg 1,0% ( 20,1) wcg_faah_autodo 1,0% ( 20,0) knotify4 0,9% ( 18,2) milestone_1.02_ Isn't it illogical to wake up CPU 1700 times/sec (with 2000/sec is a max value achieved on my CPU) to try to balance load caused by two threads, when both are designed to eat 100% of core running on? In my opinion load balancer should be disabled od throttled way down when cores load is above specified treshold. No, the timeslice is 1ms. You'll enter the scheduler 1000 times a second per CPU assuming a fully loaded system. If your CPU is busy then wakeups cost you nothing. Maybe costs me nothing, naybe not- a fact is that due to additional CPU work CPU is warmer and I can't pass through 5h on battery barrier whatever I do or I don't. When kernel hadn't mentioned bug/feature this score was easy to achieve. You're seeing far more userspace wakeups than you were before, which would explain a lot of that. |