diff options
| author |   Vineet Gupta <vgupta@synopsys.com> | 2015-12-11 15:54:03 +0530 |
|---|---|---|
| committer | Vineet Gupta <vgupta@synopsys.com> | 2015-12-12 16:03:41 +0530 |
| commit | 8eb0984bf4fe82237f95481ff0afe514a676c717 (patch) | |
| tree | 864b158f037ea3dc27d0afdd4659ef70243a48aa /arch/arc | |
| parent | ARC: [axs10x] cap ethernet phy to 100 Mbit/sec (diff) | |
| download | linux-dev-8eb0984bf4fe82237f95481ff0afe514a676c717.tar.xz linux-dev-8eb0984bf4fe82237f95481ff0afe514a676c717.zip | |
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>
Diffstat (limited to 'arch/arc')
| -rw-r--r-- | arch/arc/kernel/intc-arcv2.c | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/arch/arc/kernel/intc-arcv2.c b/arch/arc/kernel/intc-arcv2.c index 26c156827479..0394f9f61b46 100644 --- a/arch/arc/kernel/intc-arcv2.c +++ b/arch/arc/kernel/intc-arcv2.c @@ -106,10 +106,21 @@ static struct irq_chip arcv2_irq_chip = { static int arcv2_irq_map(struct irq_domain *d, unsigned int irq, irq_hw_number_t hw) { - if (irq == TIMER0_IRQ || irq == IPI_IRQ) + /* + * core intc IRQs [16, 23]: + * Statically assigned always private-per-core (Timers, WDT, IPI, PCT) + */ + if (hw < 24) { + /* + * A subsequent request_percpu_irq() fails if percpu_devid is + * not set. That in turns sets NOAUTOEN, meaning each core needs + * to call enable_percpu_irq() + */ + irq_set_percpu_devid(irq); irq_set_chip_and_handler(irq, &arcv2_irq_chip, handle_percpu_irq); - else + } else { irq_set_chip_and_handler(irq, &arcv2_irq_chip, handle_level_irq); + } return 0; } |