Re: [REGRESSION] sudden cpu hogging in kernel 3.2 rc-series

From: Mike Galbraith
Date: Tue Nov 22 2011 - 00:04:31 EST


On Mon, 2011-11-21 at 22:40 +0100, Nicolas Kalkhof wrote:
> This happens on my machine after some minutes, too when running X and
> the trinity desktop. the cpu continuously uses up additional ~10 watts
> comparing to older 3.1 kernels. The issue remains high even after I
> kill X. A closer investigation shows that poll_idle uses up the cpu
> (see dump below). Is it normal for poll_idle to use up all ressources?

poll_idle should not consume cycles on i7 unless you booted idle=poll,
or miss-configured the kernel.

egrep 'IDLE|GOV' .config

CONFIG_ARCH_HAS_CPU_IDLE_WAIT=y
CONFIG_ARCH_HAS_DEFAULT_IDLE=y
CONFIG_CPU_FREQ_DEFAULT_GOV_PERFORMANCE=y
# CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE is not set
# CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND is not set
# CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE is not set
CONFIG_CPU_FREQ_GOV_PERFORMANCE=y
CONFIG_CPU_FREQ_GOV_POWERSAVE=m
CONFIG_CPU_FREQ_GOV_USERSPACE=m
CONFIG_CPU_FREQ_GOV_ONDEMAND=m
CONFIG_CPU_FREQ_GOV_CONSERVATIVE=m
CONFIG_CPU_IDLE=y
CONFIG_CPU_IDLE_GOV_LADDER=y
CONFIG_CPU_IDLE_GOV_MENU=y
CONFIG_INTEL_IDLE=y
CONFIG_I7300_IDLE_IOAT_CHANNEL=y
CONFIG_I7300_IDLE=m
CONFIG_DEVFREQ_GOV_SIMPLE_ONDEMAND=y
CONFIG_DEVFREQ_GOV_PERFORMANCE=y
CONFIG_DEVFREQ_GOV_POWERSAVE=y
CONFIG_DEVFREQ_GOV_USERSPACE=y


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/