ondemand: cpu load calculation with kernel processus

DISCUSSION Nicolas Capit 2 participants 3 messages May 31, 2007 – Jun 1, 2007

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Nicolas Capit

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2007-05-31 21:57 UTC #0 lore raw

Hello,

I am running a Debian unstable with a kernel 2.6.21-1-686 and using modules powernow_k8 and cpufreq_ondemand.

My configuration with the ondemand governor seems to work very well except when my cpu is busy by the kernel processus kcryptd. The cpu is 100% busy but the frequency is not increased.
(I am using the module dm_crypt to encrypt my home filesystem)

So my question is:
Does the ondemand governor calculate the load of the machine with user level and *kernel* level processus?

Thanks,

Nicolas.

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Len Brown

2007-06-01 00:57 UTC #1 lore raw

Quoted 5 lines · Nicolas Capit

Hello,
I am running a Debian unstable with a kernel 2.6.21-1-686 and using modules powernow_k8 and cpufreq_ondemand.

Quoted 8 lines

My configuration with the ondemand governor seems to work very well except when my cpu is busy by the kernel processus kcryptd. The cpu is 100% busy but the frequency is not increased.
(I am using the module dm_crypt to encrypt my home filesystem)
So my question is:
Does the ondemand governor calculate the load of the machine with user level and *kernel* level processus?

both user and kernel time should count as busy time.

do the cpu stats exposed by top show that you have idle time available?

-Len

Nicolas Capit

author

2007-06-01 01:57 UTC #2 lore raw

Quoted 11 lines · On Thu, 31 May 2007 20:57:45 -0400 Len Brown <[email protected]> wrote:

Quoted 10 lines · Nicolas Capit
Hello,
I am running a Debian unstable with a kernel 2.6.21-1-686 and using modules powernow_k8 and cpufreq_ondemand.
My configuration with the ondemand governor seems to work very well except when my cpu is busy by the kernel processus kcryptd. The cpu is 100% busy but the frequency is not increased.
(I am using the module dm_crypt to encrypt my home filesystem)

Quoted 7 lines

Quoted 3 lines
So my question is:
Does the ondemand governor calculate the load of the machine with user level and *kernel* level processus?
both user and kernel time should count as busy time.
do the cpu stats exposed by top show that you have idle time available?

Ok I am sorry for the noise :-(
My program that get the CPU stats is buggy... with top, effectively the CPU is 0% idle but 10%us and 90%wa
(wa : Amount of time the CPU has been waiting for I/O to complete.)

Except if increasing the CPU frequency will reduce I/O wait time, the cpufreq_ondemand works well...

Quoted 3 lines

-Len