From: "Brown, Len" <len.brown@intel.com>
To: Holger Macht <hmacht@suse.de>
Cc: thoenig@suse.de, linux-acpi@vger.kernel.org,
linux-laptop@vger.kernel.org, Andi Kleen <ak@suse.de>
Subject: RE: kernel vs user power management
Date: Wed, 17 May 2006 00:20:12 -0400 [thread overview]
Message-ID: <CFF307C98FEABE47A452B27C06B85BB679B59B@hdsmsx411.amr.corp.intel.com> (raw)
>> >> I'm happy to see that clock throttling is not enabled by
>> >> default in recent SuSE release, at least on my laptop
>> >> which supports P-states.
>> >>
>> >> I'd like to see no option to enable clock-throttling on
>> >> systems that support real p-states.
>> >
>> >Yes, this is reasonable, indeen. Will do that. With p-states in this
>> >context, you mean cpufreq here?
>>
>> throttling is always T-states.
>> cpufreq is usually p-states, but in the case of p4clockmod,
>> it is T-states also. As I mentioned above, cpufreq is doing
>> you a dis-service by hiding the difference from you
>> and really need to be enhanced to know (and export)
>> the difference.
>
>Yes, this would be good, indeed. But what else drivers are currently
>affected? It's only p4clockmod I know of.
>
>>
>> >> It is useful only for workloads which have an infinite
>> >> amount of non-idle computing which you don't care how
>> >> slow it computes. For the vast majority of workloads
>> >> it just slows down the machine and delays the processor
>> >> from getting into idle where it can save a non-linear
>> >> amount of power. Further, there exist today systems which
>> >> will consume MORE power in deep C-states when throttled
>> >> vs. when not throttled.
I installed SL10.1 today on a P3M laptop (Dell D600)
and it defaults to the "Powersave" scheme which includes
"Dynamic Frequency Scaling" (ondemand), so that is good.
However, by defaulit "Allow Throttling" is CHECKED
and Max % is set to 50%.
Exactly what does this mean?
I looked in /proc/acpi/processor/*/throttling and the
laptop is still in T0.
Is there an easy way for me to modify the kernel to
convince the powersaved application that the system
does not support throttling? I'm thinking that we've
given user-space too much rope and it has proceeded
to hang itself.
thanks,
-Len
next reply other threads:[~2006-05-17 4:20 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-05-17 4:20 Brown, Len [this message]
2006-05-17 9:14 ` kernel vs user power management Holger Macht
-- strict thread matches above, loose matches on Subject: below --
2006-05-17 18:25 Brown, Len
2006-05-17 15:41 Brown, Len
2006-05-17 17:41 ` Holger Macht
2006-04-09 3:06 Brown, Len
2006-04-09 6:07 ` Andi Kleen
2006-04-10 8:35 ` Holger Macht
2006-04-08 6:42 Brown, Len
2006-04-08 17:18 ` Holger Macht
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