Am Dienstag, 29. Mai 2007 18:20:06 schrieb Peter Oruba:
> Am Dienstag, 29. Mai 2007 18:06:21 schrieben Sie:
> > On Tue, May 29, 2007 at 03:47:00PM +0200, Peter Oruba wrote:
> > > Dave,
> > >
> > > I am contacting you regarding a frequency scaling issue that I encountered with the performance governor in combination with CPU hotplug. In cpufreq.c CPU frequency is reduced to its
> > > minimum before the CPU gets unregistered and set offline. Does that have a particular reason? Since the (k8-)governor does not monitor CPU frequency that setting also applies then to the remaining CPU
> > > as well and lets the system run on the lowest frequency although performance is chose as the policy.
> > >
> > > ---
> > > static int cpufreq_cpu_callback(struct notifier_block *nfb,
> > > unsigned long action, void *hcpu)
> > > {
> > >
> > > [......]
> > >
> > > case CPU_DOWN_PREPARE_FROZEN:
> > > if (unlikely(lock_policy_rwsem_write(cpu)))
> > > BUG();
> > >
> > > policy = cpufreq_cpu_data[cpu];
> > > if (policy) {
> > > __cpufreq_driver_target(policy, policy->min,
> > > CPUFREQ_RELATION_H);
> > > }
> > > __cpufreq_remove_dev(sys_dev);
> >
> > This is the path taken when we call suspend.
> > To be honest, I doubt that reducing the speed has any benefit at all,
> > as we're about to put the CPU to sleep anyway.
> >
> > (btw, in future sending questions to [email protected] is a better
> > idea. The subsystem is sufficiently complex that at times, others can
> > answer questions better than I can, especially with the various
> > implementations all being subtley different).
> >
> > Thanks,
> >
> > Dave
> >
> Okay, removing the __cpufreq_driver_target call would solve would obviously solve that problem (which btw also exists on Core2, as I tested a couple of minutes ago). Is it planned to be changed
> in the near future?
>
> Thanks,
> Peter
>
My patch, aimed at that issue.
Signed-off by: Peter Oruba <[email protected]>
---
--- cpufreq/drivers/cpufreq/cpufreq.c.orig 2007-06-04 18:30:57.000000000 +0200
+++ cpufreq/drivers/cpufreq/cpufreq.c 2007-06-04 18:43:01.000000000 +0200
@@ -1698,11 +1698,6 @@ static int cpufreq_cpu_callback(struct n
if (unlikely(lock_policy_rwsem_write(cpu)))
BUG();
- policy = cpufreq_cpu_data[cpu];
- if (policy) {
- __cpufreq_driver_target(policy, policy->min,
- CPUFREQ_RELATION_H);
- }
__cpufreq_remove_dev(sys_dev);
break;
case CPU_DOWN_FAILED:
---
--
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