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[82.127.83.212]) by mx.google.com with ESMTPSA id q13sm12311485wie.8.2013.04.25.10.24.54 for (version=TLSv1.1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Thu, 25 Apr 2013 10:24:56 -0700 (PDT) From: Vincent Guittot To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linaro-kernel@lists.linaro.org, peterz@infradead.org, mingo@kernel.org, linux@arm.linux.org.uk, pjt@google.com, santosh.shilimkar@ti.com, Morten.Rasmussen@arm.com, chander.kashyap@linaro.org, cmetcalf@tilera.com, tony.luck@intel.com, alex.shi@intel.com, preeti@linux.vnet.ibm.com Subject: [PATCH 04/14] sched: pack the idle load balance Date: Thu, 25 Apr 2013 19:23:20 +0200 Message-Id: <1366910611-20048-5-git-send-email-vincent.guittot@linaro.org> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1366910611-20048-1-git-send-email-vincent.guittot@linaro.org> References: <1366910611-20048-1-git-send-email-vincent.guittot@linaro.org> X-Gm-Message-State: ALoCoQnwlfC/1KzG7FTrdhvPy1Y3MAFrULujGnvLkdKCzaA6qyva+oyWRxAjO+OwBHhMUZ02ZHR5 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20130425_132459_016692_B0307111 X-CRM114-Status: GOOD ( 11.80 ) X-Spam-Score: -1.9 (-) X-Spam-Report: SpamAssassin version 3.3.2 on merlin.infradead.org summary: Content analysis details: (-1.9 points) pts rule name description ---- ---------------------- -------------------------------------------------- -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Cc: len.brown@intel.com, l.majewski@samsung.com, Vincent Guittot , corbet@lwn.net, amit.kucheria@linaro.org, tglx@linutronix.de, paulmck@linux.vnet.ibm.com, arjan@linux.intel.com X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org Look for an idle CPU close to the pack buddy CPU whenever possible. The goal is to prevent the wake up of a CPU which doesn't share the power domain of the pack buddy CPU. Signed-off-by: Vincent Guittot Reviewed-by: Morten Rasmussen --- kernel/sched/fair.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 6adc57c..a985c98 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -5469,7 +5469,26 @@ static struct { static inline int find_new_ilb(int call_cpu) { + struct sched_domain *sd; int ilb = cpumask_first(nohz.idle_cpus_mask); + int buddy = per_cpu(sd_pack_buddy, call_cpu); + + /* + * If we have a pack buddy CPU, we try to run load balance on a CPU + * that is close to the buddy. + */ + if (buddy != -1) { + for_each_domain(buddy, sd) { + if (sd->flags & SD_SHARE_CPUPOWER) + continue; + + ilb = cpumask_first_and(sched_domain_span(sd), + nohz.idle_cpus_mask); + + if (ilb < nr_cpu_ids) + break; + } + } if (ilb < nr_cpu_ids && idle_cpu(ilb)) return ilb;