Messages in this thread | | | Date | Tue, 29 Nov 2011 01:31:49 +0530 | From | "Srivatsa S. Bhat" <> | Subject | Re: Too many poll_idle cpu calls in kernel 3.2 rc-series |
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Adding linux-pm mailing list to CC.
Thanks, Srivatsa S. Bhat
On 11/28/2011 01:43 AM, Nicolas Kalkhof wrote:
> the kernel v3.2 series shows excessive poll_idle calls during system idle phases causing the cpu > (mobile i7 2620M) to heat up and draw additional 10% more power. All kernel versions between > 3.2-rc1 and 3.2-rc3 are affected. Perf Top and Powertop both show the same issue. > I've posted a similar bug report before: http://marc.info/?l=linux-kernel&m=132164909313594&w=2 > and used perf top -U to verify the poll_idle calls as requested. > > dmesg and kernel .config attached. > > Could someone please confirm this issue? > > Thanks and Regards > Nic > > perf top -U shows: > Events: 30K cycles > 97.88% [kernel] [k] poll_idle > 0.17% [kernel] [k] sdhci_irq > 0.08% [kernel] [k] unix_poll > 0.06% [kernel] [k] _raw_spin_lock_irqsave > 0.06% [kernel] [k] page_fault > 0.05% [kernel] [k] fget_light > 0.05% [kernel] [k] format_decode > 0.04% [kernel] [k] kmem_cache_alloc > 0.04% [kernel] [k] clear_page > 0.04% [kernel] [k] _raw_spin_unlock_irqrestore > 0.03% [kernel] [k] do_select > 0.03% [kernel] [k] seq_printf > 0.03% [kernel] [k] vfs_read > 0.03% [kernel] [k] _raw_spin_lock > 0.03% [kernel] [k] vsnprintf > 0.03% [kernel] [k] number.clone.1 > 0.03% [kernel] [k] fput > > Powertop shows: > n Avg residency P-states (frequencies) > C0 (cpu running) ( 5.4%) Turbo Mode 1.5% > polling 1.8ms (94.6%) 2.71 Ghz 0.1% > C1 mwait 0.0ms ( 0.0%) 2.21 Ghz 0.1% > C2 mwait 0.0ms ( 0.0%) 1400 Mhz 0.1% > C3 mwait 0.0ms ( 0.0%) 800 Mhz 98.2% > C4 mwait 0.0ms ( 0.0%) > Wakeups-from-idle per second : 529.4 interval: 5.0s >
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