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oprofile: Remove 'WQ on CPUx, prefer CPUy' warning 

Under certain workloads we see the following warnings:

 WQ on CPU0, prefer CPU1
 WQ on CPU0, prefer CPU2
 WQ on CPU0, prefer CPU3

It warns the user that the wq to access a per-cpu buffers runs not on
the same cpu. This happens if the wq is rescheduled on a different cpu
than where the buffer is located. This was probably implemented to
detect performance issues. Not sure if there actually is one as the
buffers are copied to a single buffer anyway which should be the
actual bottleneck.

We wont change WQ implementation. Since a user can do nothing the
warning is pointless. Removing it.

Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Robert Richter <robert.richter@amd.com>
This commit is contained in:
Robert Richter 2012-08-22 09:23:51 +02:00
parent 81ff3478d9
commit 61bccf191f
1 changed files with 3 additions and 8 deletions
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7
drivers/oprofile/cpu_buffer.c
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@ -451,15 +451,10 @@ static void wq_sync_buffer(struct work_struct *work)
{
struct oprofile_cpu_buffer *b =
container_of(work, struct oprofile_cpu_buffer, work.work);
if (b->cpu != smp_processor_id()) {
printk(KERN_DEBUG "WQ on CPU%d, prefer CPU%d\n",
smp_processor_id(), b->cpu);
if (!cpu_online(b->cpu)) {
if (b->cpu != smp_processor_id() && !cpu_online(b->cpu)) {
cancel_delayed_work(&b->work);
return;
}
}
sync_buffer(b->cpu);
/* don't re-add the work if we're shutting down */