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 <npig...@gmail.com>
---
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 e9b3853d93ea..16be7ad30fe1 100644
--- a/drivers/cpuidle/cpuidle-pseries.c
+++ b/drivers/cpuidle/cpuidle-pseries.c
@@ -171,11 +171,17 @@ 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 },
};
--
2.13.3
