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Message-Id: <1382195841-6558-1-git-send-email-fweisbec@gmail.com>
Date: Sat, 19 Oct 2013 17:17:16 +0200
From: Frederic Weisbecker <fweisbec@...il.com>
To: Oleg Nesterov <oleg@...hat.com>,
Peter Zijlstra <peterz@...radead.org>
Cc: LKML <linux-kernel@...r.kernel.org>,
Frederic Weisbecker <fweisbec@...il.com>,
Fernando Luis Vazquez Cao <fernando_b1@....ntt.co.jp>,
Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...nel.org>,
Andrew Morton <akpm@...ux-foundation.org>,
Arjan van de Ven <arjan@...ux.intel.com>
Subject: [RFC PATCH 0/5] nohz: Fix racy sleeptime stats v2
Hi,
So this is a new iteration with some more changes on top of the latest discussions
we had.
Unfortunately it's not yet a real viable solution. Check out patch 4/5 for details,
I think that's too much overhead. Also it changes enough the semantics to break the
idle sleeptime accounting along the way. This is because moving the accounting to
io_schedule() makes it account _all_ IO sleeptime, even if the CPU is still busy,
not just when it is idle like before. As a result, the idle sleeptime, that relies on
a diff against the io sleeptime, is broken.
Anyway, my hope with this new take is mostly to launch a discussion with a fresher
base and see if we can find better ideas.
Thanks!
git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git
sched/iowait
Thanks,
Frederic
---
Frederic Weisbecker (5):
nohz: Convert a few places to use local per cpu accesses
nohz: Only update sleeptime stats locally
timer: Change idle/iowait accounting semantics
sched: Refactor iowait accounting
nohz: Synchronize sleep time stats with seqlock
include/linux/ktime.h | 7 +++
include/linux/sched.h | 1 +
include/linux/tick.h | 11 ++--
kernel/sched/core.c | 68 ++++++++++++++++++---
kernel/sched/cputime.c | 2 +-
kernel/sched/sched.h | 5 +-
kernel/softirq.c | 4 +-
kernel/time/tick-broadcast.c | 6 +-
kernel/time/tick-internal.h | 4 +-
kernel/time/tick-sched.c | 138 ++++++++++++++-----------------------------
kernel/time/timer_list.c | 3 +-
11 files changed, 130 insertions(+), 119 deletions(-)
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