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Filename Latest commit message Latest commit date
Vincent Guittot bc4278987e sched/fair: Fix FTQ noise bench regression
A regression of the FTQ noise has been reported by Ying Huang,
on the following hardware:

  8 threads Intel(R) Core(TM)i7-4770 CPU @ 3.40GHz with 8G memory

... which was caused by this commit:

  commit 4e5160766f ("sched/fair: Propagate asynchrous detach")

The only part of the patch that can increase the noise is the update
of blocked load of group entity in update_blocked_averages().

We can optimize this call and skip the update of group entity if its load
and utilization are already null and there is no pending propagation of load
in the task group.

This optimization partly restores the noise score. A more agressive
optimization has been tried but has shown worse score.

Reported-by: ying.huang@linux.intel.com
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dietmar.eggemann@arm.com
Cc: ying.huang@intel.com
Fixes: 4e5160766f ("sched/fair: Propagate asynchrous detach")
Link: http://lkml.kernel.org/r/1489758442-2877-1-git-send-email-vincent.guittot@linaro.org
[ Fixed typos, improved layout. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-23 07:44:51 +01:00
arch Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2017-03-15 09:26:04 -07:00
block blk-mq-sched: don't run the queue async from blk_mq_try_issue_directly() 2017-03-14 11:51:59 -06:00
certs
crypto net: Work around lockdep limitation in sockets that use sockets 2017-03-09 18:23:27 -08:00
Documentation Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-03-14 21:31:23 -07:00
drivers Merge branch 'for-linus' of git://git.kernel.dk/linux-block 2017-03-15 16:54:58 -07:00
firmware
fs Merge branch 'for-linus' of git://git.kernel.dk/linux-block 2017-03-15 16:54:58 -07:00
include SCSI fixes on 20170315 2017-03-15 10:44:19 -07:00
init Change get_random_{int,log} to use the CRNG used by /dev/urandom and 2017-03-11 09:08:47 -08:00
ipc
kernel sched/fair: Fix FTQ noise bench regression 2017-03-23 07:44:51 +01:00
lib mm: convert generic code to 5-level paging 2017-03-09 11:48:47 -08:00
mm Merge branch 'for-4.11-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu 2017-03-14 14:48:50 -07:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-03-14 21:31:23 -07:00
samples
scripts Merge branch 'akpm' (patches from Andrew) 2017-03-10 08:34:42 -08:00
security
sound scripts/spelling.txt: add "disble(d)" pattern and fix typo instances 2017-03-09 17:01:09 -08:00
tools Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-03-14 21:31:23 -07:00
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Makefile Linux 4.11-rc2 2017-03-12 14:47:08 -07:00
README

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.