Gitweb:
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=b47e8608a08766ef8121cd747d3aaf6c3dc22649
Commit: b47e8608a08766ef8121cd747d3aaf6c3dc22649
Parent: e4903fb59590f86190280a549420f6cb85bd7f7e
Author: Ingo Molnar <[EMAIL PROTECTED]>
AuthorDate: Thu Jul 26 13:40:43 2007 +0200
Committer: Ingo Molnar <[EMAIL PROTECTED]>
CommitDate: Thu Jul 26 13:40:43 2007 +0200
[PATCH] sched: increase SCHED_LOAD_SCALE_FUZZ
increase SCHED_LOAD_SCALE_FUZZ that adds a small amount of
over-balancing: to help distribute CPU-bound tasks more fairly on SMP
systems.
the problem of unfair balancing was noticed and reported by Tong N Li.
10 CPU-bound tasks running on 8 CPUs, v2.6.23-rc1:
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
2572 mingo 20 0 1576 244 196 R 100 0.0 1:03.61 loop
2578 mingo 20 0 1576 248 196 R 100 0.0 1:03.59 loop
2576 mingo 20 0 1576 248 196 R 100 0.0 1:03.52 loop
2571 mingo 20 0 1576 244 196 R 100 0.0 1:03.46 loop
2569 mingo 20 0 1576 244 196 R 99 0.0 1:03.36 loop
2570 mingo 20 0 1576 244 196 R 95 0.0 1:00.55 loop
2577 mingo 20 0 1576 248 196 R 50 0.0 0:31.88 loop
2574 mingo 20 0 1576 248 196 R 50 0.0 0:31.87 loop
2573 mingo 20 0 1576 248 196 R 50 0.0 0:31.86 loop
2575 mingo 20 0 1576 248 196 R 50 0.0 0:31.86 loop
v2.6.23-rc1 + patch:
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
2681 mingo 20 0 1576 244 196 R 85 0.0 3:51.68 loop
2688 mingo 20 0 1576 244 196 R 81 0.0 3:46.35 loop
2682 mingo 20 0 1576 244 196 R 80 0.0 3:43.68 loop
2685 mingo 20 0 1576 248 196 R 80 0.0 3:45.97 loop
2683 mingo 20 0 1576 248 196 R 80 0.0 3:40.25 loop
2679 mingo 20 0 1576 244 196 R 80 0.0 3:33.53 loop
2680 mingo 20 0 1576 244 196 R 79 0.0 3:43.53 loop
2686 mingo 20 0 1576 244 196 R 79 0.0 3:39.31 loop
2687 mingo 20 0 1576 244 196 R 78 0.0 3:33.31 loop
2684 mingo 20 0 1576 244 196 R 77 0.0 3:27.52 loop
so they now nicely converge to the expected 80% long-term CPU usage.
Signed-off-by: Ingo Molnar <[EMAIL PROTECTED]>
---
include/linux/sched.h | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 33b9b48..7c61b50 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -681,7 +681,7 @@ enum cpu_idle_type {
#define SCHED_LOAD_SHIFT 10
#define SCHED_LOAD_SCALE (1L << SCHED_LOAD_SHIFT)
-#define SCHED_LOAD_SCALE_FUZZ (SCHED_LOAD_SCALE >> 5)
+#define SCHED_LOAD_SCALE_FUZZ (SCHED_LOAD_SCALE >> 1)
#ifdef CONFIG_SMP
#define SD_LOAD_BALANCE 1 /* Do load balancing on this
domain. */
-
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