From f2ac428e0edabbca41b9dfe9473a90147962e4e9 Mon Sep 17 00:00:00 2001 From: Nicholas Piggin Date: Tue, 10 Oct 2017 17:11:09 +1000 Subject: [PATCH] powerpc/pseries/cpuidle: add polling idle for shared processor guests For shared processor guests (e.g., KVM), add an idle polling mode rather than immediately returning to the hypervisor when the guest CPU goes idle. Test setup is a 2 socket POWER9 with 4 guests running, each with vCPUs equal to 1/2 of real of CPUs. Saturated each guest with tbench. Using polling idle gives about 1.4x throughput. Kernel compile speed was not changed significantly. Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman --- drivers/cpuidle/cpuidle-pseries.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/drivers/cpuidle/cpuidle-pseries.c b/drivers/cpuidle/cpuidle-pseries.c index 0f2b697cbb27..9e56bc411061 100644 --- a/drivers/cpuidle/cpuidle-pseries.c +++ b/drivers/cpuidle/cpuidle-pseries.c @@ -174,11 +174,17 @@ static struct cpuidle_state dedicated_states[] = { * States for shared partition case. */ static struct cpuidle_state shared_states[] = { + { /* Snooze */ + .name = "snooze", + .desc = "snooze", + .exit_latency = 0, + .target_residency = 0, + .enter = &snooze_loop }, { /* Shared Cede */ .name = "Shared Cede", .desc = "Shared Cede", - .exit_latency = 0, - .target_residency = 0, + .exit_latency = 10, + .target_residency = 100, .enter = &shared_cede_loop }, }; -- GitLab