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authorAnton Blanchard <anton@samba.org>2011-03-20 15:28:03 +0000
committerGreg Kroah-Hartman <gregkh@suse.de>2011-04-14 13:02:05 -0700
commit81dacc2d64030457bfd85ba901deb17a682e6196 (patch)
tree1f8e1e01d4681aba1b9fb57630340bf8644e7682 /arch/powerpc
parentf7b5886892a642bfdc39619a63794d17ec333896 (diff)
downloadlinux-2.6.38-lt-ux500-81dacc2d64030457bfd85ba901deb17a682e6196.tar.gz
powerpc: Fix accounting of softirq time when idle
commit ad5d1c888e556bc00c4e86f452cad4a3a87d22c1 upstream. commit cf9efce0ce31 (powerpc: Account time using timebase rather than PURR) used in_irq() to detect if the time was spent in interrupt processing. This only catches hardirq context so if we are in softirq context and in the idle loop we end up accounting it as idle time. If we instead use in_interrupt() we catch both softirq and hardirq time. The issue was found when running a network intensive workload. top showed the following: 0.0%us, 1.1%sy, 0.0%ni, 85.7%id, 0.0%wa, 9.9%hi, 3.3%si, 0.0%st 85.7% idle. But this was wildly different to the perf events data. To confirm the suspicion I ran something to keep the core busy: # yes > /dev/null & 8.2%us, 0.0%sy, 0.0%ni, 0.0%id, 0.0%wa, 10.3%hi, 81.4%si, 0.0%st We only got 8.2% of the CPU for the userspace task and softirq has shot up to 81.4%. With the patch below top shows the correct stats: 0.0%us, 0.0%sy, 0.0%ni, 5.3%id, 0.0%wa, 13.3%hi, 81.3%si, 0.0%st Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'arch/powerpc')
-rw-r--r--arch/powerpc/kernel/time.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index 09d31dbf43f..aa9269600ca 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -356,7 +356,7 @@ void account_system_vtime(struct task_struct *tsk)
}
get_paca()->user_time_scaled += user_scaled;
- if (in_irq() || idle_task(smp_processor_id()) != tsk) {
+ if (in_interrupt() || idle_task(smp_processor_id()) != tsk) {
account_system_time(tsk, 0, delta, sys_scaled);
if (stolen)
account_steal_time(stolen);