linux-kernel - [PATCH 0/6] sched: Cleanup and improve polling idle loops

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Date:	Tue,  3 Jun 2014 17:29:46 -0700
From:	Andy Lutomirski <luto@...capital.net>
To:	Peter Zijlstra <peterz@...radead.org>, umgwanakikbuti@...il.com
Cc:	mingo@...nel.org, tglx@...utronix.de, nicolas.pitre@...aro.org,
	daniel.lezcano@...aro.org, linux-kernel@...r.kernel.org,
	Andy Lutomirski <luto@...capital.net>
Subject: [PATCH 0/6] sched: Cleanup and improve polling idle loops

This series reduces the number of IPIs on my workload by something like
99%.  It's down from many hundreds per second to very few.

The basic idea behind this series is to make TIF_POLLING_NRFLAG be a
reliable indication that the idle task is polling.  Once that's done,
the rest is reasonably straightforward.

Patches 1 and 2 are related improvements: patch 1 teaches the cpuidle
polling loop how to poll, and patch 2 adds tracepoints so that avoided
IPIs are visible.  Patch 3 is a pure cleanup, patch 4 is the main
semantic change, patch 5 is cleanup, and patch 6 is peterz's code,
rebased on top of my stuff, and fixed up a bit.

Andy Lutomirski (5):
  cpuidle: Set polling in poll_idle
  sched,trace: Add a tracepoint for remote wakeups via polling
  sched,idle: Clarify where TIF_NRFLAG_POLLING is set
  sched,idle: Clear polling before descheduling the idle thread
  sched,idle: Simplify wake_up_idle_cpu

Peter Zijlstra (1):
  sched: Optimize ttwu IPI

 drivers/cpuidle/driver.c     |  7 ++--
 include/trace/events/sched.h | 20 +++++++++++
 kernel/sched/core.c          | 79 +++++++++++++++++++++++++++++---------------
 kernel/sched/idle.c          | 22 +++++++++++-
 kernel/sched/sched.h         |  6 ++++
 5 files changed, 105 insertions(+), 29 deletions(-)

-- 
1.9.3

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