Message-ID: <1330466421.11248.107.camel@twins>
Subject: Re: [RFD] cgroup: about multiple hierarchies
From: Peter Zijlstra <peterz@infradead.org>
To: Vivek Goyal <vgoyal@redhat.com>
Cc: Tejun Heo <tj@kernel.org>, Li Zefan <lizf@cn.fujitsu.com>,
        containers@lists.linux-foundation.org, cgroups@vger.kernel.org,
        Andrew Morton <akpm@linux-foundation.org>,
        Kay Sievers <kay.sievers@vrfy.org>,
        Lennart Poettering <lennart@poettering.net>,
        Frederic Weisbecker <fweisbec@gmail.com>, linux-kernel@vger.kernel.org,
        Christoph Hellwig <hch@infradead.org>
Date: Tue, 28 Feb 2012 23:00:21 +0100
In-Reply-To: <20120228215439.GJ9920@redhat.com>
References: <20120221211938.GE12236@google.com>
	 <20120222163858.GB4128@redhat.com> <20120222165714.GC4128@redhat.com>
	 <1329990094.24994.64.camel@twins> <20120223213847.GK19691@redhat.com>
	 <20120223223457.GJ22536@google.com> <20120228211627.GH9920@redhat.com>
	 <1330464100.11248.94.camel@twins> <20120228213526.GI9920@redhat.com>
	 <1330465434.11248.98.camel@twins> <20120228215439.GJ9920@redhat.com>
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7BIT
Mime-Version: 1.0
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1706
Lines: 38

On Tue, 2012-02-28 at 16:54 -0500, Vivek Goyal wrote:
> On Tue, Feb 28, 2012 at 10:43:54PM +0100, Peter Zijlstra wrote:
> > On Tue, 2012-02-28 at 16:35 -0500, Vivek Goyal wrote:
> > > For
> > > cpu controller, it is priority at the group level no fixed minimum/maximum
> > > % shares. And that's a limitation of treating task and group at same level.
> > 
> > Depends on what you mean by min/max %, you can do it on the group level
> > by using bandwidth caps (for max) or inverted (max on everybody else,
> > for min).
> 
> I was referring to using pure proportional controller. max bandwidth is
> new and I am looking for a quick documentation file which describes
> what are the knobs and how to use it. Did not find any in
> Documentation/cgroups/. Is there any documentation available?

Its written in C, its at kernel/sched/fair.c ;-)

> I am assuming that max are being specified for groups in some absolute
> quantity. That is fine. It will not still be max %, as again for % you
> need fixed number of entities at any level and that's not the case with
> tasks.
> 
> Minimum for one group (max for everyone else) will also only work if 
> task and groups are not at same level.

I'm really not seeing this.

> I think the only way to get fixed % share is not to put task and group
> at same level during system configuration.

Still doesn't matter, like said, its all runnable based. If a group has
0 runnable entities it doesn't exist (more or less).
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/