LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Sven-Thorsten Dietrich <sdietrich@novell.com>
To: Pavel Machek <pavel@ucw.cz>
Cc: Gregory Haskins <ghaskins@novell.com>,
	mingo@elte.hu, a.p.zijlstra@chello.nl, tglx@linutronix.de,
	rostedt@goodmis.org, linux-rt-users@vger.kernel.org,
	linux-kernel@vger.kernel.org, bill.huey@gmail.com,
	kevin@hilman.org, cminyard@mvista.com, dsingleton@mvista.com,
	dwalker@mvista.com, npiggin@suse.de, dsaxena@plexity.net,
	ak@suse.de, acme@redhat.com, gregkh@suse.de,
	pmorreale@novell.com, mkohari@novell.com
Subject: Re: [(RT RFC) PATCH v2 6/9] add a loop counter based timeout mechanism
Date: Mon, 25 Feb 2008 14:39:29 -0800	[thread overview]
Message-ID: <1203979169.16711.101.camel@sven.thebigcorporation.com> (raw)
In-Reply-To: <20080225220601.GH2659@elf.ucw.cz>


On Mon, 2008-02-25 at 23:06 +0100, Pavel Machek wrote:
> On Mon 2008-02-25 11:01:08, Gregory Haskins wrote:
> > From: Sven Dietrich <sdietrich@novell.com>
> 
> Why is this good idea?
> 

The timeout is useful to eliminate excessive CPU utilization when
waiting for long-held critical sections. 

The patch header should state this :) Will fix.

> > Signed-off-by: Sven Dietrich <sdietrich@novell.com>
> > ---
> 
> >  
> > +config RTLOCK_DELAY
> > +	int "Default delay (in loops) for adaptive rtlocks"
> > +	range 0 1000000000
> > +	depends on ADAPTIVE_RTLOCK
> > +	default "10000"
> > +        help
> > +         This allows you to specify the maximum attempts a task will spin
> > +	 attempting to acquire an rtlock before sleeping.  The value is
> > +	 tunable at runtime via a sysctl.  A setting of 0 (zero) disables
> > +	 the adaptive algorithm entirely.
> > +
> 
> I believe you have _way_ too many config variables. If this can be set
> at runtime, does it need a config option, too?
> 

Absolutely. The sysctl was added after-the-fact, so this is a relic, we
will remove the config option, and define the default timeout in the
appropriate header.

Sven

> 									Pavel


  parent reply	other threads:[~2008-02-25 22:43 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-02-25 16:00 [(RT RFC) PATCH v2 0/9] adaptive real-time locks Gregory Haskins
2008-02-25 16:00 ` [(RT RFC) PATCH v2 1/9] allow rt-mutex lock-stealing to include lateral priority Gregory Haskins
2008-03-03 15:13   ` Steven Rostedt
2008-03-03 15:41     ` [(RT RFC) PATCH v2 1/9] allow rt-mutex lock-stealing to includelateral priority Gregory Haskins
2008-03-03 15:55       ` Steven Rostedt
2008-03-03 15:55         ` [(RT RFC) PATCH v2 1/9] allow rt-mutex lock-stealing toincludelateral priority Gregory Haskins
2008-02-25 16:00 ` [(RT RFC) PATCH v2 2/9] sysctl for runtime-control of lateral mutex stealing Gregory Haskins
2008-02-25 21:53   ` Pavel Machek
2008-02-25 22:57     ` Sven-Thorsten Dietrich
2008-02-25 23:00       ` Pavel Machek
2008-02-25 23:40         ` Sven-Thorsten Dietrich
2008-02-26  1:15       ` Gregory Haskins
2008-02-25 16:00 ` [(RT RFC) PATCH v2 3/9] rearrange rt_spin_lock sleep Gregory Haskins
2008-02-25 21:54   ` Pavel Machek
2008-02-26  0:45     ` Gregory Haskins
2008-02-25 16:00 ` [(RT RFC) PATCH v2 4/9] optimize rt lock wakeup Gregory Haskins
2008-03-03 15:37   ` Steven Rostedt
2008-03-03 15:41     ` Gregory Haskins
2008-02-25 16:01 ` [(RT RFC) PATCH v2 5/9] adaptive real-time lock support Gregory Haskins
2008-02-25 22:03   ` Pavel Machek
2008-02-26  0:48     ` Gregory Haskins
2008-02-26 15:03     ` Gregory Haskins
2008-02-26 18:06       ` Pavel Machek
2008-02-26 18:01         ` Gregory Haskins
2008-02-25 16:01 ` [(RT RFC) PATCH v2 6/9] add a loop counter based timeout mechanism Gregory Haskins
2008-02-25 22:06   ` Pavel Machek
2008-02-25 22:19     ` Greg KH
2008-02-25 22:21       ` Pavel Machek
2008-02-25 22:39     ` Sven-Thorsten Dietrich [this message]
2008-02-26 15:09     ` Gregory Haskins
2008-02-25 16:01 ` [(RT RFC) PATCH v2 7/9] adaptive mutexes Gregory Haskins
2008-02-25 22:09   ` Pavel Machek
2008-02-26  0:52     ` Gregory Haskins
2008-02-25 16:01 ` [(RT RFC) PATCH v2 8/9] adjust pi_lock usage in wakeup Gregory Haskins
2008-02-25 22:10   ` Pavel Machek
2008-02-25 16:01 ` [(RT RFC) PATCH v2 9/9] remove the extra call to try_to_take_lock Gregory Haskins

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=1203979169.16711.101.camel@sven.thebigcorporation.com \
    --to=sdietrich@novell.com \
    --cc=a.p.zijlstra@chello.nl \
    --cc=acme@redhat.com \
    --cc=ak@suse.de \
    --cc=bill.huey@gmail.com \
    --cc=cminyard@mvista.com \
    --cc=dsaxena@plexity.net \
    --cc=dsingleton@mvista.com \
    --cc=dwalker@mvista.com \
    --cc=ghaskins@novell.com \
    --cc=gregkh@suse.de \
    --cc=kevin@hilman.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-rt-users@vger.kernel.org \
    --cc=mingo@elte.hu \
    --cc=mkohari@novell.com \
    --cc=npiggin@suse.de \
    --cc=pavel@ucw.cz \
    --cc=pmorreale@novell.com \
    --cc=rostedt@goodmis.org \
    --cc=tglx@linutronix.de \
    --subject='Re: [(RT RFC) PATCH v2 6/9] add a loop counter based timeout mechanism' \
    /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

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).