Re: [patch] Real-Time Preemption, -RT-2.6.12-rc6-V0.7.47-20
From: Esben Nielsen
Date: Tue Jun 07 2005 - 10:57:27 EST
Hey,
This is an old problem of cpu_freq.c not compiling. I (re)send a fix for
it. This time as a real patch...
Esben
--- drivers/cpufreq/cpufreq.c.orig 2005-06-07 15:47:25.000000000 +0200
+++ drivers/cpufreq/cpufreq.c 2005-06-07 16:31:01.000000000 +0200
@@ -605,7 +605,8 @@
policy->cpu = cpu;
policy->cpus = cpumask_of_cpu(cpu);
- init_MUTEX_LOCKED(&policy->lock);
+ init_MUTEX(&policy->lock);
+ down(&policy->lock);
init_completion(&policy->kobj_unregister);
INIT_WORK(&policy->update, handle_update, (void *)(long)cpu);
On Tue, 7 Jun 2005, Ingo Molnar wrote:
>
> i have released the -V0.7.47-20 Real-Time Preemption patch, which can be
> downloaded from the usual place:
>
> http://redhat.com/~mingo/realtime-preempt/
>
> i've implemented two new features:
>
> - new debugging feature: CONFIG_DEBUG_RT_LOCKING_MODE, which
> adds the /proc/sys/kernel/preempt_locks flag (default: 0). This way
> the 'locking model' can be switched runtime - very useful for
> debugging and profiling. Value 0 means that all spinlocks and rwlocks
> are implemented via raw spinlocks/rwlocks. (which disable preemption,
> increase latency, but improve throughput) Value 1 means the kernel
> will fully preempt all locks again. (NOTE: the only safe runtime
> switching of the locking model can be done while the system is idle,
> so i've implemented the flag via two flags where the idle thread
> propagates the new value from the user-flag to the kernel-flag. You
> should put a "sleep 1" into scripts that switch the locking mode, to
> guarantee that the new flag value is picked up.)
>
> - performance feature: i've implemented a new scheduler feature called
> 'delayed preemption', which turns sync wakeups into guaranteed
> wakeups, while preserving their workload-batching properties. A
> delayed preemption request is implemented via the
> TIF_NEED_RESCHED_DELAYED flag, which runs in parallel to the
> "immediate preemption" TIF_NEED_RESCHED flag. If this works out fine
> then it will be a suitable replacement for the upstream sync-wakeups
> facility as well.
>
> delayed preemption already improved the performance of 'hackbench' under
> PREEMPT_RT quite signifiantly.
>
> to build a -V0.7.47-20 tree, the following patches have to be applied:
>
> http://kernel.org/pub/linux/kernel/v2.6/linux-2.6.11.tar.bz2
> http://kernel.org/pub/linux/kernel/v2.6/testing/patch-2.6.12-rc6.bz2
> http://redhat.com/~mingo/realtime-preempt/realtime-preempt-2.6.12-rc6-V0.7.47-20
>
> Ingo
> -
> 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/
>
-
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/