>-----Original Message-----
>From: Ingo Molnar [mailto:mingo@xxxxxxx]
>Sent: Wednesday, February 25, 2009 10:58 AM
>To: Metzger, Markus T
>* Metzger, Markus T <markus.t.metzger@xxxxxxxxx> wrote:
>
>> > static void trace_bts_prepare(struct trace_iterator *iter)
>> > {
>> >- mutex_lock(&bts_tracer_mutex);
>> >+ spin_lock(&bts_tracer_lock);
>> >
>> > on_each_cpu(trace_bts_cpu, iter->tr, 1);
>> >
>> >- mutex_unlock(&bts_tracer_mutex);
>> >+ spin_unlock(&bts_tracer_lock);
>> > }
>>
>> Whereas start/stop are relatively fast, the above operation is
>> rather expensive. Would it make sense to use
>> schedule_on_each_cpu() instead of on_each_cpu()?
>
>it's perfectly fine to do that on_each_cpu() under the spinlock.
>schedule_on_each_cpu() would likely be more expensive - and for
>no good reason.
OK.
And I assume you like the spinlock better than the
get/put_online_cpus(), as well.
regards,
markus.
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