Messages in this thread Patch in this message | | | From | Vineet Gupta <> | Subject | [PATCH 1/3] ARCv2: intc: Fix random perf irq disabling in SMP setup | Date | Fri, 11 Dec 2015 16:49:11 +0530 |
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As part of fixing another perf issue, observed that after a perf run, the interrupt got disabled on one/more cores.
| [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
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.
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> --- arch/arc/kernel/intc-arcv2.c | 15 +++++++++++++-- 1 file 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; } -- 1.9.1
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