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Date: Fri, 11 Jul 2014 07:22:07 +0800
From: Yuyang Du <yuyang.du@intel.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: bsegall@google.com, mingo@redhat.com, linux-kernel@vger.kernel.org,
        rafael.j.wysocki@intel.com, arjan.van.de.ven@intel.com,
        len.brown@intel.com, alan.cox@intel.com, mark.gross@intel.com,
        pjt@google.com, fengguang.wu@intel.com
Subject: Re: [PATCH 2/2] sched: Rewrite per entity runnable load average
 tracking
Message-ID: <20140710232207.GC12984@intel.com>
References: <1404268256-3019-1-git-send-email-yuyang.du@intel.com>
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On Thu, Jul 10, 2014 at 12:08:59PM +0200, Peter Zijlstra wrote:
> 
> Since clock_task is the regular clock minus some local amount, the
> difference between two regular clock reads is always a strict upper
> bound on clock_task differences.
> 
This is inspiring. Regarding the clock source in load avg tracking,
should we simply use rq_clock_task instead of cfs_rq_clock_task.

For the bandwidth control case, just update/increase the last_update_time when
unthrottled by this throttled time, so the time would look like freezed. Am I
understanding right?

Not sure how much bandwidth control is used, but even not used, every time
we read cfs_rq_clock_task, will burn useless cycles here.

Thanks,
Yuyang