Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759544Ab3CGQeV (ORCPT ); Thu, 7 Mar 2013 11:34:21 -0500 Received: from terminus.zytor.com ([198.137.202.10]:56915 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752029Ab3CGQeT (ORCPT ); Thu, 7 Mar 2013 11:34:19 -0500 Date: Thu, 7 Mar 2013 08:33:07 -0800 From: tip-bot for Daniel Lezcano Message-ID: Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@kernel.org, tglx@linutronix.de, daniel.lezcano@linaro.org Reply-To: mingo@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org, tglx@linutronix.de, daniel.lezcano@linaro.org In-Reply-To: <1362219013-18173-3-git-send-email-daniel.lezcano@linaro.org> References: <1362219013-18173-3-git-send-email-daniel.lezcano@linaro.org> To: linux-tip-commits@vger.kernel.org Subject: [tip:timers/core] tick: Dynamically set broadcast irq affinity Git-Commit-ID: d2348fb6fdc6d671ad45b62db237f76c8c115603 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.7 (terminus.zytor.com [127.0.0.1]); Thu, 07 Mar 2013 08:33:14 -0800 (PST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5611 Lines: 155 Commit-ID: d2348fb6fdc6d671ad45b62db237f76c8c115603 Gitweb: http://git.kernel.org/tip/d2348fb6fdc6d671ad45b62db237f76c8c115603 Author: Daniel Lezcano AuthorDate: Sat, 2 Mar 2013 11:10:11 +0100 Committer: Thomas Gleixner CommitDate: Thu, 7 Mar 2013 16:13:26 +0100 tick: Dynamically set broadcast irq affinity When a cpu goes to a deep idle state where its local timer is shutdown, it notifies the time frame work to use the broadcast timer instead. Unfortunately, the broadcast device could wake up any CPU, including an idle one which is not concerned by the wake up at all. So in the worst case an idle CPU will wake up to send an IPI to the CPU whose timer expired. Provide an opt-in feature CLOCK_EVT_FEAT_DYNIRQ which tells the core that is should set the interrupt affinity of the broadcast interrupt to the cpu which has the earliest expiry time. This avoids unnecessary spurious wakeups and IPIs. [ tglx: Adopted to cpumask rework, silenced an uninitialized warning, massaged changelog ] Signed-off-by: Daniel Lezcano Cc: viresh.kumar@linaro.org Cc: jacob.jun.pan@linux.intel.com Cc: linux-arm-kernel@lists.infradead.org Cc: santosh.shilimkar@ti.com Cc: linaro-kernel@lists.linaro.org Cc: patches@linaro.org Cc: rickard.andersson@stericsson.com Cc: vincent.guittot@linaro.org Cc: linus.walleij@stericsson.com Cc: john.stultz@linaro.org Link: http://lkml.kernel.org/r/1362219013-18173-3-git-send-email-daniel.lezcano@linaro.org Signed-off-by: Thomas Gleixner --- include/linux/clockchips.h | 5 +++++ kernel/time/tick-broadcast.c | 39 +++++++++++++++++++++++++++++++-------- 2 files changed, 36 insertions(+), 8 deletions(-) diff --git a/include/linux/clockchips.h b/include/linux/clockchips.h index 6634652..494d33e 100644 --- a/include/linux/clockchips.h +++ b/include/linux/clockchips.h @@ -55,6 +55,11 @@ enum clock_event_nofitiers { #define CLOCK_EVT_FEAT_C3STOP 0x000008 #define CLOCK_EVT_FEAT_DUMMY 0x000010 +/* + * Core shall set the interrupt affinity dynamically in broadcast mode + */ +#define CLOCK_EVT_FEAT_DYNIRQ 0x000020 + /** * struct clock_event_device - clock event device descriptor * @event_handler: Assigned by the framework to be called by the low diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c index 70dd98c..380910d 100644 --- a/kernel/time/tick-broadcast.c +++ b/kernel/time/tick-broadcast.c @@ -401,13 +401,34 @@ struct cpumask *tick_get_broadcast_oneshot_mask(void) return tick_broadcast_oneshot_mask; } -static int tick_broadcast_set_event(struct clock_event_device *bc, +/* + * Set broadcast interrupt affinity + */ +static void tick_broadcast_set_affinity(struct clock_event_device *bc, + const struct cpumask *cpumask) +{ + if (!(bc->features & CLOCK_EVT_FEAT_DYNIRQ)) + return; + + if (cpumask_equal(bc->cpumask, cpumask)) + return; + + bc->cpumask = cpumask; + irq_set_affinity(bc->irq, bc->cpumask); +} + +static int tick_broadcast_set_event(struct clock_event_device *bc, int cpu, ktime_t expires, int force) { + int ret; + if (bc->mode != CLOCK_EVT_MODE_ONESHOT) clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT); - return clockevents_program_event(bc, expires, force); + ret = clockevents_program_event(bc, expires, force); + if (!ret) + tick_broadcast_set_affinity(bc, cpumask_of(cpu)); + return ret; } int tick_resume_broadcast_oneshot(struct clock_event_device *bc) @@ -436,7 +457,7 @@ static void tick_handle_oneshot_broadcast(struct clock_event_device *dev) { struct tick_device *td; ktime_t now, next_event; - int cpu; + int cpu, next_cpu = 0; raw_spin_lock(&tick_broadcast_lock); again: @@ -447,10 +468,12 @@ again: /* Find all expired events */ for_each_cpu(cpu, tick_broadcast_oneshot_mask) { td = &per_cpu(tick_cpu_device, cpu); - if (td->evtdev->next_event.tv64 <= now.tv64) + if (td->evtdev->next_event.tv64 <= now.tv64) { cpumask_set_cpu(cpu, tmpmask); - else if (td->evtdev->next_event.tv64 < next_event.tv64) + } else if (td->evtdev->next_event.tv64 < next_event.tv64) { next_event.tv64 = td->evtdev->next_event.tv64; + next_cpu = cpu; + } } /* @@ -473,7 +496,7 @@ again: * Rearm the broadcast device. If event expired, * repeat the above */ - if (tick_broadcast_set_event(dev, next_event, 0)) + if (tick_broadcast_set_event(dev, next_cpu, next_event, 0)) goto again; } raw_spin_unlock(&tick_broadcast_lock); @@ -515,7 +538,7 @@ void tick_broadcast_oneshot_control(unsigned long reason) if (!cpumask_test_and_set_cpu(cpu, tick_broadcast_oneshot_mask)) { clockevents_set_mode(dev, CLOCK_EVT_MODE_SHUTDOWN); if (dev->next_event.tv64 < bc->next_event.tv64) - tick_broadcast_set_event(bc, dev->next_event, 1); + tick_broadcast_set_event(bc, cpu, dev->next_event, 1); } } else { if (cpumask_test_and_clear_cpu(cpu, tick_broadcast_oneshot_mask)) { @@ -581,7 +604,7 @@ void tick_broadcast_setup_oneshot(struct clock_event_device *bc) clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT); tick_broadcast_init_next_event(tmpmask, tick_next_period); - tick_broadcast_set_event(bc, tick_next_period, 1); + tick_broadcast_set_event(bc, cpu, tick_next_period, 1); } else bc->next_event.tv64 = KTIME_MAX; } else { -- 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/