Subject: Re: [RFC][PATCH v2 4/7] taskstats: Add per task steal time
 accounting
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
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
In-Reply-To: <20101111170815.024542355@linux.vnet.ibm.com>
References: <20101111170352.732381138@linux.vnet.ibm.com>
	 <20101111170815.024542355@linux.vnet.ibm.com>
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Date: Sat, 13 Nov 2010 20:38:02 +0100
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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?
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