Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933441AbbHJJzE (ORCPT ); Mon, 10 Aug 2015 05:55:04 -0400 Received: from mail-wi0-f176.google.com ([209.85.212.176]:38226 "EHLO mail-wi0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933316AbbHJJyl (ORCPT ); Mon, 10 Aug 2015 05:54:41 -0400 From: Daniel Lezcano To: mingo@kernel.org Cc: tglx@linutronix.de, linux-kernel@vger.kernel.org, Jisheng Zhang Subject: [PATCH 52/74] clockevents/drivers/dw_apb_timer: Add dynamic irq flag to the timer Date: Mon, 10 Aug 2015 11:52:09 +0200 Message-Id: <1439200352-26767-52-git-send-email-daniel.lezcano@linaro.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1439200352-26767-1-git-send-email-daniel.lezcano@linaro.org> References: <55C87382.4070309@linaro.org> <1439200352-26767-1-git-send-email-daniel.lezcano@linaro.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6542 Lines: 142 From: Jisheng Zhang Commit d2348fb6fdc6 ("tick: Dynamically set broadcast irq affinity") adds one excellent feature CLOCK_EVT_FEAT_DYNIRQ to let the core set the interrupt affinity of the broadcast interrupt to the cpu which has the earliest expiry time. This patch adds CLOCK_EVT_FEAT_DYNIRQ flag to avoid unnecessary wakeups and IPIs when the dw_apb_timer is used as broadcast timer. A simple test: ~ # rm /tmp/test.sh ~ # cat > /tmp/test.sh cat /proc/interrupts for i in `seq 10` ; do sleep $i; done cat /proc/interrupts ~ # chmod +x /tmp/test.sh ~ # taskset 0x2 /tmp/test.sh without the patch: CPU0 CPU1 27: 115 36 GIC 27 arch_timer 45: 62 0 GIC 45 mmc0 160: 88 0 interrupt-controller 8 timer 227: 0 0 interrupt-controller 4 f7e81400.i2c 228: 0 0 interrupt-controller 5 f7e81800.i2c 229: 0 0 interrupt-controller 7 dw_spi65535 230: 0 0 interrupt-controller 21 f7e84000.i2c 231: 0 0 interrupt-controller 20 f7e84800.i2c 265: 445 0 interrupt-controller 8 serial IPI0: 0 0 CPU wakeup interrupts IPI1: 0 11 Timer broadcast interrupts IPI2: 56 104 Rescheduling interrupts IPI3: 0 0 Function call interrupts IPI4: 0 4 Single function call interrupts IPI5: 0 0 CPU stop interrupts IPI6: 25 27 IRQ work interrupts IPI7: 0 0 completion interrupts IPI8: 0 0 CPU backtrace Err: 0 CPU0 CPU1 27: 115 38 GIC 27 arch_timer 45: 62 0 GIC 45 mmc0 160: 160 0 interrupt-controller 8 timer 227: 0 0 interrupt-controller 4 f7e81400.i2c 228: 0 0 interrupt-controller 5 f7e81800.i2c 229: 0 0 interrupt-controller 7 dw_spi65535 230: 0 0 interrupt-controller 21 f7e84000.i2c 231: 0 0 interrupt-controller 20 f7e84800.i2c 265: 514 0 interrupt-controller 8 serial IPI0: 0 0 CPU wakeup interrupts IPI1: 0 83 Timer broadcast interrupts IPI2: 56 104 Rescheduling interrupts IPI3: 0 0 Function call interrupts IPI4: 0 4 Single function call interrupts IPI5: 0 0 CPU stop interrupts IPI6: 25 46 IRQ work interrupts IPI7: 0 0 completion interrupts IPI8: 0 0 CPU backtrace Err: 0 cpu0 get 160-88=72 timer interrupts, CPU1 got 83-11=72 broadcast timer IPIs So, overall system got 72+72=144 wake ups and 72 broadcast timer IPIs With the patch: CPU0 CPU1 27: 107 37 GIC 27 arch_timer 45: 62 0 GIC 45 mmc0 160: 66 7 interrupt-controller 8 timer 227: 0 0 interrupt-controller 4 f7e81400.i2c 228: 0 0 interrupt-controller 5 f7e81800.i2c 229: 0 0 interrupt-controller 7 dw_spi65535 230: 0 0 interrupt-controller 21 f7e84000.i2c 231: 0 0 interrupt-controller 20 f7e84800.i2c 265: 311 0 interrupt-controller 8 serial IPI0: 0 0 CPU wakeup interrupts IPI1: 2 4 Timer broadcast interrupts IPI2: 58 100 Rescheduling interrupts IPI3: 0 0 Function call interrupts IPI4: 0 4 Single function call interrupts IPI5: 0 0 CPU stop interrupts IPI6: 21 24 IRQ work interrupts IPI7: 0 0 completion interrupts IPI8: 0 0 CPU backtrace Err: 0 CPU0 CPU1 27: 107 39 GIC 27 arch_timer 45: 62 0 GIC 45 mmc0 160: 69 75 interrupt-controller 8 timer 227: 0 0 interrupt-controller 4 f7e81400.i2c 228: 0 0 interrupt-controller 5 f7e81800.i2c 229: 0 0 interrupt-controller 7 dw_spi65535 230: 0 0 interrupt-controller 21 f7e84000.i2c 231: 0 0 interrupt-controller 20 f7e84800.i2c 265: 380 0 interrupt-controller 8 serial IPI0: 0 0 CPU wakeup interrupts IPI1: 3 6 Timer broadcast interrupts IPI2: 60 100 Rescheduling interrupts IPI3: 0 0 Function call interrupts IPI4: 0 4 Single function call interrupts IPI5: 0 0 CPU stop interrupts IPI6: 21 45 IRQ work interrupts IPI7: 0 0 completion interrupts IPI8: 0 0 CPU backtrace Err: 0 cpu0 got 69-66=3, cpu1 got 75-7=68 timer interrupts. cpu0 got 3-2=1 broadcast timer IPIs, cpu1 got 6-4=2 broadcast timer IPIs. So, overall system got 3+68+1+2=74 wakeups and 1+2=3 broadcast timer IPIs This patch removes 50% wakeups and almost 100% broadcast timer IPIs! Signed-off-by: Jisheng Zhang Signed-off-by: Daniel Lezcano --- drivers/clocksource/dw_apb_timer.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/clocksource/dw_apb_timer.c b/drivers/clocksource/dw_apb_timer.c index 97ba7cb..c76c750 100644 --- a/drivers/clocksource/dw_apb_timer.c +++ b/drivers/clocksource/dw_apb_timer.c @@ -248,7 +248,8 @@ dw_apb_clockevent_init(int cpu, const char *name, unsigned rating, &dw_ced->ced); dw_ced->ced.min_delta_ns = clockevent_delta2ns(5000, &dw_ced->ced); dw_ced->ced.cpumask = cpumask_of(cpu); - dw_ced->ced.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT; + dw_ced->ced.features = CLOCK_EVT_FEAT_PERIODIC | + CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_DYNIRQ; dw_ced->ced.set_state_shutdown = apbt_shutdown; dw_ced->ced.set_state_periodic = apbt_set_periodic; dw_ced->ced.set_state_oneshot = apbt_set_oneshot; -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/