Messages in this thread | | | From | Vincent Guittot <> | Date | Wed, 10 Sep 2014 16:19:56 +0200 | Subject | Re: [PATCH v5 06/12] sched: add per rq cpu_capacity_orig |
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On 10 September 2014 15:53, Peter Zijlstra <peterz@infradead.org> wrote: > On Tue, Aug 26, 2014 at 01:06:49PM +0200, Vincent Guittot wrote: >> This new field cpu_capacity_orig reflects the available capacity of a CPUs >> unlike the cpu_capacity which reflects the current capacity that can be altered >> by frequency and rt tasks. >> > > No real objection to the patch as such, but the Changelog fails to tell > us why you want this.
the cpu_capacity_orig is used in several places in the following patches to detect when a CPU's capacity has been noticeably reduced so we can trig load balance to look for a CPU with full capacity. As an example, we can detect when a CPU handles a significant amount of irq (with CONFIG_IRQ_TIME_ACCOUNTING) but is seen as an idle CPU by scheduler whereas really idle CPU are available
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