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>

diff --git a/drivers/oprofile/cpu_buffer.c b/drivers/oprofile/cpu_buffer.c
index b8ef8dd..8aa73fa 100644 (file)
--- a/drivers/oprofile/cpu_buffer.c
+++ b/drivers/oprofile/cpu_buffer.c
@@ -451,14 +451,9 @@ 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)) {
-                       cancel_delayed_work(&b->work);
-                       return;
-               }
+       if (b->cpu != smp_processor_id() && !cpu_online(b->cpu)) {
+               cancel_delayed_work(&b->work);
+               return;
        }
        sync_buffer(b->cpu);