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From: Gregory Haskins <ghaskins@novell.com>
To: LKML <linux-kernel@vger.kernel.org>,
	Steven Rostedt <srostedt@redhat.com>
Cc: Christoph Lameter <clameter@sgi.com>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	Ingo Molnar <mingo@elte.hu>,
	Gregory Haskins <ghaskins@novell.com>
Subject: [PATCH 1/4] Fix optimized search
Date: Tue, 20 Nov 2007 23:44:06 -0500	[thread overview]
Message-ID: <20071121044406.6315.82159.stgit@novell1.haskins.net> (raw)
In-Reply-To: <20071121043648.6315.29246.stgit@novell1.haskins.net>

Include cpu 0 in the search, and eliminate the redundant cpu_set since
the bit should already be set in the mask.

Signed-off-by: Gregory Haskins <ghaskins@novell.com>
---

 kernel/sched_rt.c |    7 +++----
 1 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c
index 28feeff..fbf4fb1 100644
--- a/kernel/sched_rt.c
+++ b/kernel/sched_rt.c
@@ -297,7 +297,7 @@ static DEFINE_PER_CPU(cpumask_t, local_cpu_mask);
 static int find_lowest_cpus(struct task_struct *task, cpumask_t *lowest_mask)
 {
 	int       lowest_prio = -1;
-	int       lowest_cpu  = 0;
+	int       lowest_cpu  = -1;
 	int       count       = 0;
 	int       cpu;
 
@@ -319,7 +319,7 @@ static int find_lowest_cpus(struct task_struct *task, cpumask_t *lowest_mask)
 			 * and the count==1 will cause the algorithm
 			 * to use the first bit found.
 			 */
-			if (lowest_cpu) {
+			if (lowest_cpu != -1) {
 				cpus_clear(*lowest_mask);
 				cpu_set(rq->cpu, *lowest_mask);
 			}
@@ -335,7 +335,6 @@ static int find_lowest_cpus(struct task_struct *task, cpumask_t *lowest_mask)
 				lowest_cpu = cpu;
 				count = 0;
 			}
-			cpu_set(rq->cpu, *lowest_mask);
 			count++;
 		} else
 			cpu_clear(cpu, *lowest_mask);
@@ -346,7 +345,7 @@ static int find_lowest_cpus(struct task_struct *task, cpumask_t *lowest_mask)
 	 * runqueues that were of higher prio than
 	 * the lowest_prio.
 	 */
-	if (lowest_cpu) {
+	if (lowest_cpu != -1) {
 		/*
 		 * Perhaps we could add another cpumask op to
 		 * zero out bits. Like cpu_zero_bits(cpumask, nrbits);


  reply	other threads:[~2007-11-21  5:04 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-11-21  1:00 [PATCH v4 00/20] New RT Balancing version 4 Steven Rostedt
2007-11-21  1:00 ` [PATCH v4 01/20] Add rt_nr_running accounting Steven Rostedt
2007-11-21  1:00 ` [PATCH v4 02/20] track highest prio queued on runqueue Steven Rostedt
2007-11-21  1:00 ` [PATCH v4 03/20] push RT tasks Steven Rostedt
2007-11-21  1:00 ` [PATCH v4 04/20] RT overloaded runqueues accounting Steven Rostedt
2007-11-21  1:00 ` [PATCH v4 05/20] pull RT tasks Steven Rostedt
2007-11-21  1:01 ` [PATCH v4 06/20] wake up balance RT Steven Rostedt
2007-11-21  1:01 ` [PATCH v4 07/20] disable CFS RT load balancing Steven Rostedt
2007-11-21  1:01 ` [PATCH v4 08/20] Cache cpus_allowed weight for optimizing migration Steven Rostedt
2007-11-21  1:01 ` [PATCH v4 09/20] RT: Consistency cleanup for this_rq usage Steven Rostedt
2007-11-21  1:01 ` [PATCH v4 10/20] RT: Remove some CFS specific code from the wakeup path of RT tasks Steven Rostedt
2007-11-21  1:01 ` [PATCH v4 11/20] RT: Break out the search function Steven Rostedt
2007-11-21  1:01 ` [PATCH v4 12/20] RT: Allow current_cpu to be included in search Steven Rostedt
2007-11-21  1:01 ` [PATCH v4 13/20] RT: Pre-route RT tasks on wakeup Steven Rostedt
2007-11-21  1:01 ` [PATCH v4 14/20] RT: Optimize our cpu selection based on topology Steven Rostedt
2007-11-21  1:01 ` [PATCH v4 15/20] RT: Optimize rebalancing Steven Rostedt
2007-11-21  1:01 ` [PATCH v4 16/20] Avoid overload Steven Rostedt
2007-11-21  1:01 ` [PATCH v4 17/20] RT: restore the migratable conditional Steven Rostedt
2007-11-21  1:01 ` [PATCH v4 18/20] Optimize cpu search with hamming weight Steven Rostedt
2007-11-21  1:01 ` [PATCH v4 19/20] Optimize out cpu_clears Steven Rostedt
2007-11-21  2:10   ` Steven Rostedt
2007-11-21  3:10     ` [PATCH] Fix optimized search Gregory Haskins
2007-11-21  4:15       ` Steven Rostedt
2007-11-21  4:26         ` Steven Rostedt
2007-11-21  5:14           ` Gregory Haskins
2007-11-21  1:01 ` [PATCH v4 20/20] balance RT tasks no new wake up Steven Rostedt
2007-11-21  4:44 ` [PATCH 0/4] more RT balancing enhancements Gregory Haskins
2007-11-21  4:44   ` Gregory Haskins [this message]
2007-11-21  4:44   ` [PATCH 2/4] RT: Add sched-domain roots Gregory Haskins
2007-11-21  4:44   ` [PATCH 3/4] RT: Only balance our RT tasks within our root-domain Gregory Haskins
2007-11-21  4:44   ` [PATCH 4/4] RT: Use a 2-d bitmap for searching lowest-pri CPU Gregory Haskins
2007-11-21 19:51   ` [PATCH 0/4] more RT balancing enhancements v6a Gregory Haskins
2007-11-21 19:52     ` [PATCH 1/4] SCHED: Add sched-domain roots Gregory Haskins
2007-11-21 19:52     ` [PATCH 2/4] SCHED: Track online cpus in the root-domain Gregory Haskins
2007-11-21 19:52     ` [PATCH 3/4] SCHED: Only balance our RT tasks within our root-domain Gregory Haskins
2007-11-21 19:52     ` [PATCH 4/4] SCHED: Use a 2-d bitmap for searching lowest-pri CPU Gregory Haskins

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