Vineet Gupta
8eb0984bf4
ARCv2: intc: Fix random perf irq disabling in SMP setup
...
As part of fixing another perf issue, observed that after a perf run,
the interrupt got disabled on one/more cores.
Turns out that despite requesting perf irq as percpu, the flow handler
registered was not handle_percpu_irq()
Given that on ARCv2 cores, IRQs < 24 are always private to cpu, we
register the right handler at the very onset.
Before Fix
| [ARCLinux]# cat /proc/interrupts | grep perf
| 20: 0 0 0 0 ARCv2 core Intc 20 ARC perf counters
|
| [ARCLinux]# perf record -c 20000 /sbin/hackbench
| Running with 10*40 (== 400) tasks.
|
| [ARCLinux]# cat /proc/interrupts | grep perf
| 20: 0 522 8 51916 ARCv2 core Intc 20 ARC perf counters
|
| [ARCLinux]# perf record -c 20000 /sbin/hackbench
| Running with 10*40 (== 400) tasks.
|
| [ARCLinux]# cat /proc/interrupts | grep perf
| 20: 0 522 8 104368 ARCv2 core Intc 20 ARC perf counters
After Fix
| [ARCLinux]# cat /proc/interrupts | grep perf
| 20: 0 0 0 0 ARCv2 core Intc 20 ARC perf counters
|
| [ARCLinux]# perf record -c 20000 /sbin/hackbench
| Running with 10*40 (== 400) tasks.
|
| [ARCLinux]# cat /proc/interrupts | grep perf
| 20: 64198 62012 62697 67803 ARCv2 core Intc 20 ARC perf counters
|
| [ARCLinux]# perf record -c 20000 /sbin/hackbench
| Running with 10*40 (== 400) tasks.
|
| [ARCLinux]# cat /proc/interrupts | grep perf
| 20: 126014 122792 123301 133654 ARCv2 core Intc 20 ARC perf counters
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Alexey Brodkin <abrodkin@synopsys.com>
Cc: stable@vger.kernel.org #4.2+
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2015-12-12 16:03:41 +05:30
