[Skiboot] [PATCH] SLW : Increase stop4-5 residency by 5x

Stewart Smith stewart at flamingspork.com
Fri Nov 22 02:29:28 AEDT 2019

On Thu, Nov 21, 2019, at 4:10 AM, Abhishek Goel wrote:
> Using ppdcf2d run, we observed that there was a drop of about 50%
> throughput with stop4/5. In this benchmark the GPU waits on the cpu to
> wakeup and provide the subsequent data block to compute. CPUs serving
> GPUs workloads are idle enough for the current residency values for the
> governor to pick up stop4/5 states for those CPUs. The higher wakeup
> latency of these deep states accumulates over the run and shows up as a
> performance drop.
> We observe no perfromance drop with increased residency values.

What other workloads does this affect and how?

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