linux.kernel - 26 new messages in 13 topics - digest

linux.kernel
http://groups.google.com/group/linux.kernel?hl=en

linux.kernel@googlegroups.com

Today's topics:

* sched: Rate-limit nohz - 4 messages, 1 author
http://groups.google.com/group/linux.kernel/t/bb2824874ddfedaf?hl=en
* drivers/ata: use .dev.of_node instead of .node in struct of_device - 3
messages, 3 authors
http://groups.google.com/group/linux.kernel/t/2014a315f2e95e8a?hl=en
* drivers/input/of: don't use deprecated field in of_platform_driver - 9
messages, 1 author
http://groups.google.com/group/linux.kernel/t/8b1263e5db754a32?hl=en
* Linux kernel - Libata bad block error handling to user mode program - 1
messages, 1 author
http://groups.google.com/group/linux.kernel/t/43729a69ccf0463d?hl=en
* x86,perf: Implement minimal P4 PMU driver v14 - 1 messages, 1 author
http://groups.google.com/group/linux.kernel/t/56fce9a45008d100?hl=en
* [PATCH 1/1] perf: add support for arch-dependent symbolic event names to "
perf stat" - 1 messages, 1 author
http://groups.google.com/group/linux.kernel/t/d9c6c63579142582?hl=en
* x86, UV: Fix target_cpus() in x2apic_uv_x.c - 1 messages, 1 author
http://groups.google.com/group/linux.kernel/t/11fa4843ab7a25a9?hl=en
* perf record: Mention paranoid sysctl when failing to create counter - 1
messages, 1 author
http://groups.google.com/group/linux.kernel/t/95a47219c591dda1?hl=en
* perf record: Don't try to find buildids in a zero sized file - 1 messages, 1
author
http://groups.google.com/group/linux.kernel/t/e6c593ba24369a45?hl=en
* BNX2: Kernel crashes with 2.6.31 and 2.6.31.9 - 1 messages, 1 author
http://groups.google.com/group/linux.kernel/t/c0235d6a433f1e2b?hl=en
* trivial: remove no longer working email address - 1 messages, 1 author
http://groups.google.com/group/linux.kernel/t/90c5a95c77da91b0?hl=en
* RAID + LUKS + LVM performance - 1 messages, 1 author
http://groups.google.com/group/linux.kernel/t/43ac9c2556338695?hl=en
* lxfb_core: support 800x480 panel - 1 messages, 1 author
http://groups.google.com/group/linux.kernel/t/dee9c668ea1f68af?hl=en

==============================================================================
TOPIC: sched: Rate-limit nohz
http://groups.google.com/group/linux.kernel/t/bb2824874ddfedaf?hl=en
==============================================================================

== 1 of 4 ==
Date: Thurs, Mar 11 2010 10:40 am
From: tip-bot for Mike Galbraith

Commit-ID: 39c0cbe2150cbd848a25ba6cdb271d1ad46818ad
Gitweb: http://git.kernel.org/tip/39c0cbe2150cbd848a25ba6cdb271d1ad46818ad
Author: Mike Galbraith <efault@gmx.de>
AuthorDate: Thu, 11 Mar 2010 17:17:13 +0100
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Thu, 11 Mar 2010 18:32:49 +0100

sched: Rate-limit nohz

Entering nohz code on every micro-idle is costing ~10% throughput for netperf
TCP_RR when scheduling cross-cpu. Rate limiting entry fixes this, but raises
ticks a bit. On my Q6600, an idle box goes from ~85 interrupts/sec to 128.

The higher the context switch rate, the more nohz entry costs. With this patch
and some cycle recovery patches in my tree, max cross cpu context switch rate is
improved by ~16%, a large portion of which of which is this ratelimiting.

Signed-off-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1268301003.6785.28.camel@marge.simson.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
include/linux/sched.h | 6 ++++++
kernel/sched.c | 12 ++++++++++++
kernel/time/tick-sched.c | 3 +++
3 files changed, 21 insertions(+), 0 deletions(-)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 8cc863d..13efe7d 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -271,11 +271,17 @@ extern cpumask_var_t nohz_cpu_mask;
#if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ)
extern int select_nohz_load_balancer(int cpu);
extern int get_nohz_load_balancer(void);
+extern int nohz_ratelimit(int cpu);
#else
static inline int select_nohz_load_balancer(int cpu)
{
return 0;
}
+
+static inline int nohz_ratelimit(int cpu)
+{
+ return 0;
+}