Li, Aubrey wrote:
> Bill.Holler wrote:
>
>
>> Very cool!
>>
>> Can this heuristic be applied to C-State power domains as well?
>>
>>
> I doubt it. We don't need polling mechanism for c-state. c-state transition
> has a different event driving.
>
> With the new change of p-state, is the transtion already removed from
> the polling scanning of the current pm framework?
>
Not yet, I was waiting to take a look at the cpu_deep_idle changes Bill
is working on so that I could implement something similar to specify
using PAD vs the polling mechanism. I'll work on this next...
Thanks,
-Eric
> Thanks,
> -Aubrey
>
>
>> On 10/07/08 16:55, Eric Saxe wrote:
>>
>>> I've just been testing some changes I made to improve the PAD
>>> P-state transition policy.
>>>
>>> Before, PAD would ramp up the max speed as soon as the P-state domain
>>> went non-idle, and then ramp it back down the instant it goes idle
>>> again.
>>>
>>> Running this script on that kernel, focusing on an idle CPU:
>>>
>>> #!/usr/sbin/dtrace -s
>>>
>>> #pragma D option quiet
>>>
>>>
>>>>> ess_transition
>>>>>
>>> /curcpu->cpu_id == $1/
>>> {
>>> x++;
>>> }
>>>
>>> profile-1s
>>> /x > 0/
>>> {
>>> printf("%d\n", x);
>>> x = 0;
>>> }
>>>
>>> I would get ~140 transitions per second. With the new changes, we
>>> don't transition an idle P-state domain up to full speed until the
>>> first thread that begins running there either makes it through one
>>> time quantum, or transitions to another non-idle thread. This gets
>>> rid of the transitions we were doing simply as a result of transient
>>> background kernel activity, reducing the rate down to 2-4
>>> transitions per second...and 0 per second once the domains are
>>> busy....
>>>
>>> -Eric
>>> _______________________________________________
>>> tesla-dev mailing list
>>> tesla-dev at opensolaris.org
>>> http://mail.opensolaris.org/mailman/listinfo/tesla-dev
>>>
>>>
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>
>
