From: Peter Zijlstra <peterz@infradead.org>
To: Jan Kara <jack@suse.cz>
Cc: Wu Fengguang <fengguang.wu@intel.com>,
LKML <linux-kernel@vger.kernel.org>,
linux-mm@kvack.org
Subject: Re: [PATCH 2/2] block: Convert BDI proportion calculations to flexible proportions
Date: Fri, 18 May 2012 16:34:37 +0200 [thread overview]
Message-ID: <1337351677.573.44.camel@twins> (raw)
In-Reply-To: <20120518142443.GA6875@quack.suse.cz>
On Fri, 2012-05-18 at 16:24 +0200, Jan Kara wrote:
> Yeah, that should be easy enough so I'll try it that way since I presume
> it's nicer to power usage to use deferred timers if it's reasonably
> possible.
Btw, your current scheme also drifts. Since you do jiffes + 3*HZ you
period might actually be longer if the timer got delayed.
If you keep an external jiffies count like:
unsigned long period_jiffies = jiffies;
void my_timer_func()
{
unsigned long delta = jiffies - period_jiffies;
unsigned long periods = delta / 3*HZ;
age(periods);
period_jiffies += 3*HZ * periods;
mod_timer(&my_timer, period_jiffies);
}
it all works without drift (+- bugs of course).
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
WARNING: multiple messages have this Message-ID (diff)
From: Peter Zijlstra <peterz@infradead.org>
To: Jan Kara <jack@suse.cz>
Cc: Wu Fengguang <fengguang.wu@intel.com>,
LKML <linux-kernel@vger.kernel.org>,
linux-mm@kvack.org
Subject: Re: [PATCH 2/2] block: Convert BDI proportion calculations to flexible proportions
Date: Fri, 18 May 2012 16:34:37 +0200 [thread overview]
Message-ID: <1337351677.573.44.camel@twins> (raw)
In-Reply-To: <20120518142443.GA6875@quack.suse.cz>
On Fri, 2012-05-18 at 16:24 +0200, Jan Kara wrote:
> Yeah, that should be easy enough so I'll try it that way since I presume
> it's nicer to power usage to use deferred timers if it's reasonably
> possible.
Btw, your current scheme also drifts. Since you do jiffes + 3*HZ you
period might actually be longer if the timer got delayed.
If you keep an external jiffies count like:
unsigned long period_jiffies = jiffies;
void my_timer_func()
{
unsigned long delta = jiffies - period_jiffies;
unsigned long periods = delta / 3*HZ;
age(periods);
period_jiffies += 3*HZ * periods;
mod_timer(&my_timer, period_jiffies);
}
it all works without drift (+- bugs of course).
next prev parent reply other threads:[~2012-05-18 14:34 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-15 15:43 [PATCH 0/2 v3] Flexible proportions Jan Kara
2012-05-15 15:43 ` Jan Kara
2012-05-15 15:43 ` [PATCH 1/2] lib: Proportions with flexible period Jan Kara
2012-05-15 15:43 ` Jan Kara
2012-05-17 21:35 ` Peter Zijlstra
2012-05-17 21:35 ` Peter Zijlstra
2012-05-18 14:33 ` Jan Kara
2012-05-18 14:33 ` Jan Kara
2012-05-17 21:56 ` Peter Zijlstra
2012-05-17 21:56 ` Peter Zijlstra
2012-05-18 14:42 ` Jan Kara
2012-05-18 14:42 ` Jan Kara
2012-05-18 10:43 ` Peter Zijlstra
2012-05-18 10:43 ` Peter Zijlstra
2012-05-18 14:45 ` Jan Kara
2012-05-18 14:45 ` Jan Kara
2012-05-15 15:43 ` [PATCH 2/2] block: Convert BDI proportion calculations to flexible proportions Jan Kara
2012-05-15 15:43 ` Jan Kara
2012-05-17 22:04 ` Peter Zijlstra
2012-05-17 22:04 ` Peter Zijlstra
2012-05-18 14:24 ` Jan Kara
2012-05-18 14:24 ` Jan Kara
2012-05-18 14:34 ` Peter Zijlstra [this message]
2012-05-18 14:34 ` Peter Zijlstra
-- strict thread matches above, loose matches on Subject: below --
2012-05-24 16:59 [PATCH 0/2 v4] Flexible proportions Jan Kara
2012-05-24 16:59 ` [PATCH 2/2] block: Convert BDI proportion calculations to flexible proportions Jan Kara
2012-05-24 16:59 ` Jan Kara
2012-05-28 15:49 ` Sasha Levin
2012-05-28 15:49 ` Sasha Levin
2012-05-29 12:34 ` Jan Kara
2012-05-29 12:34 ` Jan Kara
2012-05-29 12:38 ` Peter Zijlstra
2012-05-29 12:38 ` Peter Zijlstra
2012-05-29 12:54 ` Jan Kara
2012-05-29 12:54 ` Jan Kara
2012-05-31 22:11 ` Jan Kara
2012-05-31 22:26 ` Peter Zijlstra
2012-05-31 22:26 ` Peter Zijlstra
2012-05-31 22:42 ` Jan Kara
2012-06-01 3:10 ` Fengguang Wu
2012-06-01 3:10 ` Fengguang Wu
2012-06-01 10:13 ` Peter Zijlstra
2012-06-01 10:13 ` Peter Zijlstra
2012-05-03 22:39 [PATCH 0/2 v2] Flexible proportions for BDIs Jan Kara
2012-05-03 22:39 ` [PATCH 2/2] block: Convert BDI proportion calculations to flexible proportions Jan Kara
2012-05-07 14:47 ` Fengguang Wu
2012-05-07 15:21 ` Peter Zijlstra
2012-05-09 11:38 ` Jan Kara
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=1337351677.573.44.camel@twins \
--to=peterz@infradead.org \
--cc=fengguang.wu@intel.com \
--cc=jack@suse.cz \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.