From: Frederic Weisbecker <fweisbec@gmail.com>
To: Hideaki Kimura <hideaki.kimura@hpe.com>
Cc: Jason Low <jason.low2@hp.com>, Oleg Nesterov <oleg@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
linux-kernel@vger.kernel.org,
Linus Torvalds <torvalds@linux-foundation.org>,
Steven Rostedt <rostedt@goodmis.org>,
Rik van Riel <riel@redhat.com>,
Scott J Norton <scott.norton@hp.com>
Subject: Re: [PATCH 0/3] timer: Improve itimers scalability
Date: Thu, 27 Aug 2015 15:18:49 +0200 [thread overview]
Message-ID: <20150827131844.GB21105@lerouge> (raw)
In-Reply-To: <55DE4FA8.7050701@hpe.com>
On Wed, Aug 26, 2015 at 04:45:44PM -0700, Hideaki Kimura wrote:
> I totally agree that this is not a perfect solution. If there are 10x more
> cores and sockets, just the atomic fetch_add might be too expensive.
>
> However, it's comparatively/realistically the best thing we can do without
> any drawbacks. We can't magically force all library developers to write the
> most scalable code always.
>
> My point is: this is a safety net, and a very effective one.
I mean the problem here is that a library uses an unscalable profiling feature,
unconditionally as soon as you load it without even initializing anything. And
this library is used in production.
At first sight, fixing that in the kernel is only a hack that just reduces a bit
the symptoms.
What is the technical issue that prevents from fixing that in the library itself?
Posix timers can be attached anytime.
next prev parent reply other threads:[~2015-08-27 13:18 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-26 3:17 Jason Low
2015-08-26 3:17 ` [PATCH 1/3] timer: Optimize fastpath_timer_check() Jason Low
2015-08-26 21:57 ` Frederic Weisbecker
2015-08-31 15:15 ` Davidlohr Bueso
2015-08-31 19:40 ` Jason Low
2015-08-26 3:17 ` [PATCH 2/3] timer: Check thread timers only when there are active thread timers Jason Low
2015-08-26 3:17 ` [PATCH 3/3] timer: Reduce unnecessary sighand lock contention Jason Low
2015-08-26 17:53 ` Linus Torvalds
2015-08-26 22:31 ` Frederic Weisbecker
2015-08-26 22:57 ` Jason Low
2015-08-26 22:56 ` Frederic Weisbecker
2015-08-26 23:32 ` Jason Low
2015-08-27 4:52 ` Jason Low
2015-08-27 12:53 ` Frederic Weisbecker
2015-08-27 20:29 ` Jason Low
2015-08-27 21:12 ` Frederic Weisbecker
2015-08-26 3:27 ` [PATCH 0/3] timer: Improve itimers scalability Andrew Morton
2015-08-26 16:33 ` Jason Low
2015-08-26 17:08 ` Oleg Nesterov
2015-08-26 22:07 ` Jason Low
2015-08-26 22:53 ` Hideaki Kimura
2015-08-26 23:13 ` Frederic Weisbecker
2015-08-26 23:45 ` Hideaki Kimura
2015-08-27 13:18 ` Frederic Weisbecker [this message]
2015-08-27 14:47 ` Steven Rostedt
2015-08-27 15:09 ` Thomas Gleixner
2015-08-27 15:17 ` Frederic Weisbecker
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=20150827131844.GB21105@lerouge \
--to=fweisbec@gmail.com \
--cc=akpm@linux-foundation.org \
--cc=hideaki.kimura@hpe.com \
--cc=jason.low2@hp.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@kernel.org \
--cc=oleg@redhat.com \
--cc=paulmck@linux.vnet.ibm.com \
--cc=peterz@infradead.org \
--cc=riel@redhat.com \
--cc=rostedt@goodmis.org \
--cc=scott.norton@hp.com \
--cc=tglx@linutronix.de \
--cc=torvalds@linux-foundation.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 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®