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Commit 61bccf19 authored by Robert Richter's avatar Robert Richter
Browse files

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: default avatarRobert Richter <robert.richter@amd.com>
parent 81ff3478

drivers/oprofile/cpu_buffer.c

+3 −8
Original line number Diff line number Diff line
@@ -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 */