Messages in this thread | | | Date | Thu, 17 Dec 2020 14:36:56 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH 1/4] sched/fair: Introduce primitives for CFS bandwidth burst |
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On Thu, Dec 17, 2020 at 03:46:17PM +0800, Huaixin Chang wrote: > In this patch, we introduce the notion of CFS bandwidth burst. Unused > "quota" from pervious "periods" might be accumulated and used in the > following "periods". The maximum amount of accumulated bandwidth is > bounded by "burst". And the maximun amount of CPU a group can consume in > a given period is "buffer" which is equivalent to "quota" + "burst in > case that this group has done enough accumulation.
Oh man, Juri, wasn't there a paper about statistical bandwidth accounting somewhere? Where, if you replace every utilization by a statistical variable, the end result is still useful?
That is, instead of something like; \Sum u_i <= 1, you get something like: \Sum {avg(u),var(u)}_i <= {1, sqrt(\Sum var_i^2)} and you can still proof bounded tardiness etc.. (assuming a gaussian distribution).
The proposed seems close to that, but not quite, and I'm afraid it's not quite strong enough to still provide any guarantees.
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