On Sun, 2018-04-01 at 05:48:55 UTC, Nicholas Piggin wrote: > When stop is executed with EC=ESL=0, it appears to execute like a > normal instruction (resuming from NIP when woken by interrupt). So all > the save/restore handling can be avoided completely. In particular NV > GPRs do not have to be saved, and MSR does not have to be switched > back to kernel MSR. > > So move the test for EC=ESL=0 sleep states out to power9_idle_stop, > and return directly to the caller after stop in that case. > > This improves performance for ping-pong benchmark with the stop0_lite > idle state by 2.54% for 2 threads in the same core, and 2.57% for > different cores. Performance increase with HV_POSSIBLE defined will be > improved further by avoiding the hwsync. > > Cc: Vaidyanathan Srinivasan <[email protected]> > Cc: Gautham R. Shenoy <[email protected]> > Cc: Paul Mackerras <[email protected]> > Signed-off-by: Nicholas Piggin <[email protected]>
Applied to powerpc next, thanks. https://git.kernel.org/powerpc/c/b9ee31e100e73075431faaf7af2ee0 cheers
