From mboxrd@z Thu Jan 1 00:00:00 1970 From: Viresh Kumar Subject: [PATCH V3 7/7] fbcon: queue work on any cpu Date: Mon, 18 Mar 2013 20:53:29 +0530 Message-ID: References: Cc: linaro-kernel@lists.linaro.org, robin.randhawa@arm.com, Steve.Bannister@arm.com, Liviu.Dudau@arm.com, charles.garcia-tobin@arm.com, Arvind.Chauhan@arm.com, linux-rt-users@vger.kernel.org, linux-kernel@vger.kernel.org, Viresh Kumar , Dave Airlie , linux-fbdev@vger.kernel.org To: pjt@google.com, paul.mckenney@linaro.org, tglx@linutronix.de, tj@kernel.org, suresh.b.siddha@intel.com, venki@google.com, mingo@redhat.com, peterz@infradead.org, rostedt@goodmis.org Return-path: In-Reply-To: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-rt-users.vger.kernel.org fbcon uses workqueues and it has no real dependency of scheduling these on the cpu which scheduled them. On a idle system, it is observed that and idle cpu wakes up few times just to service this work. It would be better if we can schedule it on a cpu which isn't idle to save on power. By idle cpu (from scheduler's perspective) we mean: - Current task is idle task - nr_running == 0 - wake_list is empty This patch replaces schedule_work() routine with queue_work_on_any_cpu() sibling with system_wq as workqueue. This routine would look for the closest (via scheduling domains) non-idle cpu (non-idle from schedulers perspective). If the current cpu is not idle or all cpus are idle, work will be scheduled on local cpu. Cc: Dave Airlie Cc: linux-fbdev@vger.kernel.org Signed-off-by: Viresh Kumar --- drivers/video/console/fbcon.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/video/console/fbcon.c b/drivers/video/console/fbcon.c index 3cd6759..a900997 100644 --- a/drivers/video/console/fbcon.c +++ b/drivers/video/console/fbcon.c @@ -404,7 +404,7 @@ static void cursor_timer_handler(unsigned long dev_addr) struct fb_info *info = (struct fb_info *) dev_addr; struct fbcon_ops *ops = info->fbcon_par; - schedule_work(&info->queue); + queue_work_on_any_cpu(system_wq, &info->queue); mod_timer(&ops->cursor_timer, jiffies + HZ/5); } -- 1.7.12.rc2.18.g61b472e