This is a series I came up with as a result of KS discussions. The plan was to pin the CPU C state to keep the GPU going as fast as possible while it was active, since there's some relation between the two (we don't know for sure yet, per chipset, whether it's due to latency of DMA writes having to bring CPU state up, or reduced memory bandwidth due to bus frequency reduction, or other). The actual patch series doesn't achieve that -- a hint is provided to the scheduler and cpufreq/cpuidle, which may choose not to sleep as deeply as it would otherwise.
I found a 1% performance difference in nexuiz on my Ironlake system from the last patch in this series (HEAD~1 didn't have a statistically significant effect). If that's all the difference, I'll drop this. It may pay off higher for non-Ironlake, in which case I'll work on a "proper" solution of actually clamping C-states while graphics is active. _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/intel-gfx
