mirror of https://lore.kernel.org/lkml/
 help / color / mirror / Atom feed
From: Peter Zijlstra <peterz@infradead.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
	linux-kernel@vger.kernel.org, mingo@kernel.org,
	laijs@cn.fujitsu.com, dipankar@in.ibm.com,
	akpm@linux-foundation.org, mathieu.desnoyers@efficios.com,
	josh@joshtriplett.org, niv@us.ibm.com, tglx@linutronix.de,
	rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com,
	darren@dvhart.com, fweisbec@gmail.com, sbw@mit.edu
Subject: Re: [PATCH tip/core/timers 2/4] timers: Reduce __run_timers() latency for empty list
Date: Wed, 15 Jan 2014 18:10:37 +0100	[thread overview]
Message-ID: <20140115171037.GK31570@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20140115170310.GB11499@redhat.com>

On Wed, Jan 15, 2014 at 06:03:10PM +0100, Oleg Nesterov wrote:
> On 01/14, Paul E. McKenney wrote:
> >
> > The __run_timers() function currently steps through the list one jiffy at
> > a time
> 
> And this is very suboptimal if jiffies - timer_jiffies is huge. Looks
> like, we should rework base->tv* structures, or (perhaps) optimize
> the "cascade" logic so that __run_timers() can increment timer_jiffies
> and move all the expired timers into work_list at one step. And the
> ->next_timer logic is obviously very suboptimal.

Thomas is actually actively working on a replacement for the entire
cascade mess.

  reply	other threads:[~2014-01-15 17:11 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-01-15  5:19 [PATCH v2 tip/core/timers] Crude timer-wheel latency hacks Paul E. McKenney
2014-01-15  5:20 ` [PATCH tip/core/timers 1/4] timers: Track total number of timers in list Paul E. McKenney
2014-01-15  5:20   ` [PATCH tip/core/timers 2/4] timers: Reduce __run_timers() latency for empty list Paul E. McKenney
2014-01-15 17:03     ` Oleg Nesterov
2014-01-15 17:10       ` Peter Zijlstra [this message]
2014-01-16  2:14       ` Paul E. McKenney
2014-01-15 17:38     ` Oleg Nesterov
2014-01-15 20:32       ` Josh Triplett
2014-01-15 20:47         ` Steven Rostedt
2014-01-16  2:22           ` Paul E. McKenney
2014-01-15 20:33     ` Josh Triplett
2014-01-16  2:23       ` Paul E. McKenney
2014-01-15  5:20   ` [PATCH tip/core/timers 3/4] timers: Reduce future __run_timers() latency for newly emptied list Paul E. McKenney
2014-01-15 17:08     ` Oleg Nesterov
2014-01-16  2:23       ` Paul E. McKenney
2014-01-15 20:54     ` Steven Rostedt
2014-01-15 23:41       ` Paul E. McKenney
2014-01-15  5:20   ` [PATCH tip/core/timers 4/4] timers: Reduce future __run_timers() latency for first add to empty list Paul E. McKenney
2014-01-15 17:24     ` Oleg Nesterov
2014-01-15 17:31       ` [PATCH 0/1] timers: internal_add_timer() should update ->next_timer if ->active_timers == 0 Oleg Nesterov
2014-01-15 17:31         ` [PATCH 1/1] " Oleg Nesterov
2014-01-15 20:56           ` Steven Rostedt
2014-01-16  2:10           ` Paul E. McKenney
2014-01-16  2:33       ` [PATCH tip/core/timers 4/4] timers: Reduce future __run_timers() latency for first add to empty list Paul E. McKenney
2014-01-15 22:22 ` [PATCH v2 tip/core/timers] Crude timer-wheel latency hacks Thomas Gleixner
2014-01-16  2:36   ` Paul E. McKenney

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=20140115171037.GK31570@twins.programming.kicks-ass.net \
    --to=peterz@infradead.org \
    --cc=akpm@linux-foundation.org \
    --cc=darren@dvhart.com \
    --cc=dhowells@redhat.com \
    --cc=dipankar@in.ibm.com \
    --cc=edumazet@google.com \
    --cc=fweisbec@gmail.com \
    --cc=josh@joshtriplett.org \
    --cc=laijs@cn.fujitsu.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mathieu.desnoyers@efficios.com \
    --cc=mingo@kernel.org \
    --cc=niv@us.ibm.com \
    --cc=oleg@redhat.com \
    --cc=paulmck@linux.vnet.ibm.com \
    --cc=rostedt@goodmis.org \
    --cc=sbw@mit.edu \
    --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
Powered by JetHome