From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Subject: Re: [RFC][PATCH v2 4/7] taskstats: Add per task steal time
 accounting
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
In-Reply-To: <20101111170815.024542355@linux.vnet.ibm.com>
References: <20101111170352.732381138@linux.vnet.ibm.com>
	 <20101111170815.024542355@linux.vnet.ibm.com>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 8BIT
Date: Sat, 13 Nov 2010 20:38:02 +0100
Message-ID: <1289677083.2109.167.camel@laptop>
Mime-Version: 1.0
Sender: linux-kernel-owner@vger.kernel.org
List-Archive: <https://lore.kernel.org/lkml/>
List-Post: <mailto:linux-kernel@vger.kernel.org>
To: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Cc: Shailabh Nagar <nagar1234@in.ibm.com>, Andrew Morton <akpm@linux-foundation.org>, Venkatesh Pallipadi <venki@google.com>, Suresh Siddha <suresh.b.siddha@intel.com>, Ingo Molnar <mingo@elte.hu>, Oleg Nesterov <oleg@redhat.com>, John stultz <johnstul@us.ibm.com>, Thomas Gleixner <tglx@linutronix.de>, Balbir Singh <balbir@linux.vnet.ibm.com>, Martin Schwidefsky <schwidefsky@de.ibm.com>, Heiko Carstens <heiko.carstens@de.ibm.com>, Roland McGrath <roland@redhat.com>, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org
List-ID: <linux-s390.vger.kernel.org>

On Thu, 2010-11-11 at 18:03 +0100, Michael Holzheu wrote:
> From: Michael Holzheu <holzheu@linux.vnet.ibm.com>
> 
> Currently steal time is only accounted for the whole system. With this
> patch we add steal time to the per task CPU time accounting.
> The triplet "user time", "system time" and "steal time" represents
> all consumed CPU time on hypervisor based systems. 

Does that really make sense? Its not like the hypervisor really knows
anything about tasks and won't steal from one? Its really a vcpu
feature.

What added benefit will all this extra accounting give?