From: "Daniel P. Berrange" <berrange@redhat.com>
To: Glauber Costa <glommer@parallels.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org, cgroups@vger.kernel.org,
linux-mm@kvack.org, devel@openvz.org,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Michal Hocko <mhocko@suse.cz>,
Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Mel Gorman <mgorman@suse.de>
Subject: Re: [RFC 2/4] memcg: make it suck faster
Date: Wed, 26 Sep 2012 10:03:43 +0100 [thread overview]
Message-ID: <20120926090343.GB31968@redhat.com> (raw)
In-Reply-To: <5062C281.4080805@parallels.com>
On Wed, Sep 26, 2012 at 12:53:21PM +0400, Glauber Costa wrote:
> On 09/26/2012 01:02 AM, Andrew Morton wrote:
> >> nomemcg : memcg compile disabled.
> >> > base : memcg enabled, patch not applied.
> >> > bypassed : memcg enabled, with patch applied.
> >> >
> >> > base bypassed
> >> > User 109.12 105.64
> >> > System 1646.84 1597.98
> >> > Elapsed 229.56 215.76
> >> >
> >> > nomemcg bypassed
> >> > User 104.35 105.64
> >> > System 1578.19 1597.98
> >> > Elapsed 212.33 215.76
> >> >
> >> > So as one can see, the difference between base and nomemcg in terms
> >> > of both system time and elapsed time is quite drastic, and consistent
> >> > with the figures shown by Mel Gorman in the Kernel summit. This is a
> >> > ~ 7 % drop in performance, just by having memcg enabled. memcg functions
> >> > appear heavily in the profiles, even if all tasks lives in the root
> >> > memcg.
> >> >
> >> > With bypassed kernel, we drop this down to 1.5 %, which starts to fall
> >> > in the acceptable range. More investigation is needed to see if we can
> >> > claim that last percent back, but I believe at last part of it should
> >> > be.
> > Well that's encouraging. I wonder how many users will actually benefit
> > from this - did I hear that major distros are now using memcg in some
> > system-infrastructure-style code?
> >
>
> If they do, they actually be come "users of memcg". This here is aimed
> at non-users of memcg, which given all the whining about it, it seems to
> be plenty.
>
> Also, I noticed, for instance, that libvirt is now creating memcg
> hierarchies for lxc and qemu as placeholders, before you actually create
> any vm or container.
This is mostly just lazyness on our part. There's no technical reason
why we can't delay creating our intermediate cgroups until we actually
have a VM ready to start, it was just simpler to create them when we
started the main daemon.
Daniel
--
|: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :|
|: http://libvirt.org -o- http://virt-manager.org :|
|: http://autobuild.org -o- http://search.cpan.org/~danberr/ :|
|: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|
--
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/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
WARNING: multiple messages have this Message-ID (diff)
From: "Daniel P. Berrange" <berrange@redhat.com>
To: Glauber Costa <glommer@parallels.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org, cgroups@vger.kernel.org,
linux-mm@kvack.org, devel@openvz.org,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Michal Hocko <mhocko@suse.cz>,
Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Mel Gorman <mgorman@suse.de>
Subject: Re: [RFC 2/4] memcg: make it suck faster
Date: Wed, 26 Sep 2012 10:03:43 +0100 [thread overview]
Message-ID: <20120926090343.GB31968@redhat.com> (raw)
In-Reply-To: <5062C281.4080805@parallels.com>
On Wed, Sep 26, 2012 at 12:53:21PM +0400, Glauber Costa wrote:
> On 09/26/2012 01:02 AM, Andrew Morton wrote:
> >> nomemcg : memcg compile disabled.
> >> > base : memcg enabled, patch not applied.
> >> > bypassed : memcg enabled, with patch applied.
> >> >
> >> > base bypassed
> >> > User 109.12 105.64
> >> > System 1646.84 1597.98
> >> > Elapsed 229.56 215.76
> >> >
> >> > nomemcg bypassed
> >> > User 104.35 105.64
> >> > System 1578.19 1597.98
> >> > Elapsed 212.33 215.76
> >> >
> >> > So as one can see, the difference between base and nomemcg in terms
> >> > of both system time and elapsed time is quite drastic, and consistent
> >> > with the figures shown by Mel Gorman in the Kernel summit. This is a
> >> > ~ 7 % drop in performance, just by having memcg enabled. memcg functions
> >> > appear heavily in the profiles, even if all tasks lives in the root
> >> > memcg.
> >> >
> >> > With bypassed kernel, we drop this down to 1.5 %, which starts to fall
> >> > in the acceptable range. More investigation is needed to see if we can
> >> > claim that last percent back, but I believe at last part of it should
> >> > be.
> > Well that's encouraging. I wonder how many users will actually benefit
> > from this - did I hear that major distros are now using memcg in some
> > system-infrastructure-style code?
> >
>
> If they do, they actually be come "users of memcg". This here is aimed
> at non-users of memcg, which given all the whining about it, it seems to
> be plenty.
>
> Also, I noticed, for instance, that libvirt is now creating memcg
> hierarchies for lxc and qemu as placeholders, before you actually create
> any vm or container.
This is mostly just lazyness on our part. There's no technical reason
why we can't delay creating our intermediate cgroups until we actually
have a VM ready to start, it was just simpler to create them when we
started the main daemon.
Daniel
--
|: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :|
|: http://libvirt.org -o- http://virt-manager.org :|
|: http://autobuild.org -o- http://search.cpan.org/~danberr/ :|
|: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|
next prev parent reply other threads:[~2012-09-26 9:03 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-25 8:52 [RFC 0/4] bypass charges if memcg is not used Glauber Costa
2012-09-25 8:52 ` Glauber Costa
[not found] ` <1348563173-8952-1-git-send-email-glommer-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
2012-09-25 8:52 ` [RFC 1/4] memcg: provide root figures from system totals Glauber Costa
2012-09-25 8:52 ` Glauber Costa
2012-09-25 8:52 ` Glauber Costa
[not found] ` <1348563173-8952-2-git-send-email-glommer-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
2012-10-01 17:00 ` Michal Hocko
2012-10-01 17:00 ` Michal Hocko
2012-10-01 17:00 ` Michal Hocko
2012-10-02 9:15 ` Glauber Costa
2012-10-02 9:15 ` Glauber Costa
[not found] ` <506AB0BF.9030400-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
2012-10-02 9:34 ` Michal Hocko
2012-10-02 9:34 ` Michal Hocko
2012-10-02 9:34 ` Michal Hocko
2012-09-25 8:52 ` [RFC 2/4] memcg: make it suck faster Glauber Costa
2012-09-25 8:52 ` Glauber Costa
2012-09-25 8:52 ` Glauber Costa
[not found] ` <1348563173-8952-3-git-send-email-glommer-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
2012-09-25 21:02 ` Andrew Morton
2012-09-25 21:02 ` Andrew Morton
2012-09-25 21:02 ` Andrew Morton
2012-09-26 8:53 ` Glauber Costa
2012-09-26 8:53 ` Glauber Costa
2012-09-26 9:03 ` Daniel P. Berrange [this message]
2012-09-26 9:03 ` Daniel P. Berrange
2012-09-25 8:52 ` [RFC 3/4] memcg: do not call page_cgroup_init at system_boot Glauber Costa
2012-09-25 8:52 ` Glauber Costa
2012-09-25 8:52 ` Glauber Costa
2012-09-25 8:52 ` [RFC 4/4] memcg: do not walk all the way to the root for memcg Glauber Costa
2012-09-25 8:52 ` Glauber Costa
2012-09-25 8:52 ` Glauber Costa
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=20120926090343.GB31968@redhat.com \
--to=berrange@redhat.com \
--cc=a.p.zijlstra@chello.nl \
--cc=akpm@linux-foundation.org \
--cc=cgroups@vger.kernel.org \
--cc=devel@openvz.org \
--cc=glommer@parallels.com \
--cc=hannes@cmpxchg.org \
--cc=kamezawa.hiroyu@jp.fujitsu.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mgorman@suse.de \
--cc=mhocko@suse.cz \
/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.