From: Michael J Wang Date: Mon, 19 Mar 2012 22:26:19 +0000 (+0000) Subject: sched/rt: Improve pick_next_highest_task_rt() X-Git-Tag: v3.4-rc1~42^2~1 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1b028abc779b67b699daff55e27d2432f8d92666;p=pandora-kernel.git sched/rt: Improve pick_next_highest_task_rt() Avoid extra work by continuing on to the next rt_rq if the highest prio task in current rt_rq is the same priority as our candidate task. More detailed explanation: if next is not NULL, then we have found a candidate task, and its priority is next->prio. Now we are looking for an even higher priority task in the other rt_rq's. idx is the highest priority in the current candidate rt_rq. In the current 3.3 code, if idx is equal to next->prio, we would start scanning the tasks in that rt_rq and replace the current candidate task with a task from that rt_rq. But the new task would only have a priority that is equal to our previous candidate task, so we have not advanced our goal of finding a higher prio task. So we should avoid the extra work by continuing on to the next rt_rq if idx is equal to next->prio. Signed-off-by: Michael J Wang Acked-by: Steven Rostedt Reviewed-by: Yong Zhang Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/2EF88150C0EF2C43A218742ED384C1BC0FC83D6B@IRVEXCHMB08.corp.ad.broadcom.com Signed-off-by: Ingo Molnar --- Reading git-diff-tree failed