From: Michal Hocko <mhocko@suse.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Frederic Weisbecker <fweisbecker@suse.de>,
LKML <linux-kernel@vger.kernel.org>, Mel Gorman <mgorman@suse.de>,
Ingo Molnar <mingo@redhat.com>
Subject: Re: [RFC PATCH] kernel: allow to configure PREEMPT_NONE, PREEMPT_VOLUNTARY on kernel command line
Date: Wed, 7 Oct 2020 14:29:23 +0200 [thread overview]
Message-ID: <20201007122923.GJ29020@dhcp22.suse.cz> (raw)
In-Reply-To: <20201007121939.GE2628@hirez.programming.kicks-ass.net>
On Wed 07-10-20 14:19:39, Peter Zijlstra wrote:
> On Wed, Oct 07, 2020 at 02:04:01PM +0200, Michal Hocko wrote:
> > From: Michal Hocko <mhocko@suse.com>
> >
> > Many people are still relying on pre built distribution kernels and so
> > distributions have to provide mutliple kernel flavors to offer different
> > preemption models. Most of them are providing PREEMPT_NONE for typical
> > server deployments and PREEMPT_VOLUNTARY for desktop users.
>
> Is there actually a benefit to NONE? We were recently talking about
> removing it.
I believe Mel can provide much better insight. We have been historically using
PREEMPT_NONE for our enterprise customers mostly for nice throughput
numbers. Many users are really targeting throughput much more than
latencies. My understanding is that even though VOLUNTARY preemption model
doesn't add too many preemption points on top of NONE it is still
something that is observable (IIRC 2-3% on hackbench).
> The much more interesting (runtime) switch (IMO) would be between
> VOLUNTARY and PREEMPT.
Absolutely and as said we are looking into that. This is meant to be a
first baby step in that direction. Still very useful in our current
situation when we want to provide both NONE and VOLUNTARY.
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2020-10-07 12:29 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-07 12:04 Michal Hocko
2020-10-07 12:19 ` Peter Zijlstra
2020-10-07 12:29 ` Michal Hocko [this message]
2020-10-07 13:01 ` Mel Gorman
2020-10-07 12:21 ` Peter Zijlstra
2020-10-07 12:35 ` Michal Hocko
2020-10-09 9:47 ` Peter Zijlstra
2020-10-09 10:14 ` Michal Hocko
2020-10-09 10:20 ` Peter Zijlstra
2020-10-09 10:48 ` Michal Hocko
2020-10-09 11:17 ` Michal Hocko
2020-10-09 11:26 ` Michal Hocko
2020-10-09 11:39 ` Peter Zijlstra
2020-10-09 9:12 ` Michal Hocko
2020-10-09 9:42 ` Peter Zijlstra
2020-10-09 10:10 ` Michal Hocko
2020-10-09 10:14 ` Peter Zijlstra
2020-10-09 10:37 ` Michal Hocko
2020-10-09 11:42 ` Peter Zijlstra
2020-10-09 12:29 ` [RFC PATCH v2 0/5] allow overriding default preempt mode from " Michal Hocko
2020-10-09 12:29 ` [RFC PATCH v2 1/5] jump_label: split out declaration parts into its own headers Michal Hocko
2020-10-09 12:29 ` [RFC PATCH v2 2/5] kernel: allow to configure PREEMPT_NONE, PREEMPT_VOLUNTARY on kernel command line Michal Hocko
2020-10-09 12:29 ` [RFC PATCH v2 3/5] kernel: ARCH_NO_PREEMPT shouldn't exclude PREEMPT_VOLUNTARY Michal Hocko
2020-10-09 12:29 ` [RFC PATCH v2 4/5] kernel: introduce CONFIG_PREEMPT_DYNAMIC Michal Hocko
2020-10-09 12:29 ` [RFC PATCH v2 5/5] kernel: drop PREEMPT_NONE compile time option Michal Hocko
2020-10-09 12:50 ` [RFC PATCH v2 0/5] allow overriding default preempt mode from command line Peter Zijlstra
2020-10-09 13:03 ` Michal Hocko
2020-10-09 13:22 ` Peter Zijlstra
2020-10-09 17:45 ` Peter Zijlstra
2020-10-27 12:22 ` Frederic Weisbecker
2020-10-27 12:28 ` Peter Zijlstra
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=20201007122923.GJ29020@dhcp22.suse.cz \
--to=mhocko@suse.com \
--cc=fweisbecker@suse.de \
--cc=linux-kernel@vger.kernel.org \
--cc=mgorman@suse.de \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--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®