linux/arch/arc
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
..
boot ARC: [axs10x] cap ethernet phy to 100 Mbit/sec 2015-12-07 19:40:03 +05:30
configs ARC: switch to arc-linux- CROSS_COMPILE prefix across all configs 2015-11-16 12:00:09 +05:30
include ARCv2: Use the default irq priority for idle sleep 2015-11-16 14:17:06 +05:30
kernel ARCv2: intc: Fix random perf irq disabling in SMP setup 2015-12-12 16:03:41 +05:30
lib ARCv2: lib: memcpy: use local symbols 2015-11-03 17:33:00 +05:30
mm ARC: comments update 2015-11-16 12:00:16 +05:30
oprofile
plat-axs10x ARCv2: smp: [plat-*]: No need to explicitly call mcip_init_smp() 2015-10-28 16:13:41 +05:30
plat-sim ARC: remove extraneous header include 2015-11-14 13:11:38 +05:30
plat-tb10x ARC: [plat*] move code out of .init_machine into common 2014-10-13 14:46:13 +05:30
Kbuild
Kconfig ARC: mm: PAE40 support 2015-10-29 18:41:30 +05:30
Kconfig.debug ARC: With earlycon in use, retire EARLY_PRINTK 2015-05-11 11:20:21 +05:30
Makefile arc: use common make variables for dtb builds 2015-10-27 16:12:13 -05:00