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| author | Nicholas Piggin <npiggin@gmail.com> | 2017-11-17 15:08:06 +0100 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2018-03-31 15:47:47 +0200 |
| commit | 8c1c7fb0b5ec95c392e9b585a6cf8cde254308d3 (patch) | |
| tree | 59df28bcb598514ca3c236f77e506e40a6d067ef /arch/powerpc/kernel/idle_book3s.S | |
| parent | powerpc/64s/idle: POWER9 implement a separate idle stop function for hotplug (diff) | |
| download | linux-8c1c7fb0b5ec95c392e9b585a6cf8cde254308d3.tar.xz linux-8c1c7fb0b5ec95c392e9b585a6cf8cde254308d3.zip | |
powerpc/64s/idle: avoid sync for KVM state when waking from idle
When waking from a CPU idle instruction (e.g., nap or stop), the sync
for ordering the KVM secondary thread state can be avoided if there
wakeup is coming from a kernel context rather than KVM context.
This improves performance for ping-pong benchmark with the stop0 idle
state by 0.46% for 2 threads in the same core, and 1.02% for different
cores.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/kernel/idle_book3s.S')
| -rw-r--r-- | arch/powerpc/kernel/idle_book3s.S | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/idle_book3s.S b/arch/powerpc/kernel/idle_book3s.S index 2896ccf3138d..903ec2a5c76c 100644 --- a/arch/powerpc/kernel/idle_book3s.S +++ b/arch/powerpc/kernel/idle_book3s.S @@ -551,6 +551,9 @@ ALT_FTR_SECTION_END_IFSET(CPU_FTR_ARCH_300) mr r3,r12 #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE + lbz r0,HSTATE_HWTHREAD_STATE(r13) + cmpwi r0,KVM_HWTHREAD_IN_KERNEL + beq 1f li r0,KVM_HWTHREAD_IN_KERNEL stb r0,HSTATE_HWTHREAD_STATE(r13) /* Order setting hwthread_state vs. testing hwthread_req */ |