mirror of https://lore.kernel.org/lkml/
 help / color / mirror / Atom feed
From: Serge Belyshev <belyshev@depni.sinp.msu.ru>
To: Matthew Wilcox <matthew@wil.cx>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Arjan van de Ven <arjan@infradead.org>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Prevent users from disabling tickless
Date: Sun, 02 Jan 2011 10:59:38 +0000	[thread overview]
Message-ID: <87zkrj4llx.fsf@depni.sinp.msu.ru> (raw)
In-Reply-To: <20101221233942.GL1263@parisc-linux.org> (Matthew Wilcox's message of "Tue, 21 Dec 2010 16:39:43 -0700")

Matthew Wilcox <matthew@wil.cx> writes:

> Disabling NO_HZ has a serious negative effect on performance -- an extra
> 70us per I/O.  Prevent users from deselecting it.

This is rather non-trivial change.

The common wisdom was that NO_HZ=y *adds* overhead, not removes it.
Thus, I propose:

(1) Retaining and elaborating the help text.
(2) Allow user to change the default.

  parent reply	other threads:[~2011-01-02 10:59 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-12-21 23:39 Matthew Wilcox
2010-12-21 23:46 ` Rafael J. Wysocki
2010-12-22  0:24   ` Matthew Wilcox
2010-12-22  0:38     ` Rafael J. Wysocki
2010-12-22 21:00 ` Frank Rowand
2010-12-22 21:34   ` Matthew Wilcox
2010-12-22 22:32     ` Frank Rowand
2010-12-26 22:22   ` Len Brown
2010-12-26 23:20     ` Grant Coady
2010-12-26 23:23     ` Regarding kernel work queue issues Raj Kumar
2010-12-25 15:42 ` [PATCH] Prevent users from disabling tickless Stefan Richter
2011-01-02  8:57 ` Pavel Machek
2011-01-02  9:15   ` Eric Dumazet
2011-01-02 10:59 ` Serge Belyshev [this message]
2011-01-02 11:06 ` Remy Bohmer

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=87zkrj4llx.fsf@depni.sinp.msu.ru \
    --to=belyshev@depni.sinp.msu.ru \
    --cc=arjan@infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=matthew@wil.cx \
    --cc=tglx@linutronix.de \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox

all inboxes | Powered by JetHome®