@@ -1048,6 +1048,11 @@ void __init kvm_spinlock_init(void)
return;
}
+ if (kvm_para_has_feature(KVM_FEATURE_STEAL_TIME)) {
+ pv_ops.lock.vcpu_is_preempted =
+ PV_CALLEE_SAVE(__kvm_vcpu_is_preempted);
+ }
+
/*
* Disable PV spinlocks and use native qspinlock when dedicated pCPUs
* are available.
@@ -1076,10 +1081,6 @@ void __init kvm_spinlock_init(void)
pv_ops.lock.wait = kvm_wait;
pv_ops.lock.kick = kvm_kick_cpu;
- if (kvm_para_has_feature(KVM_FEATURE_STEAL_TIME)) {
- pv_ops.lock.vcpu_is_preempted =
- PV_CALLEE_SAVE(__kvm_vcpu_is_preempted);
- }
/*
* When PV spinlock is enabled which is preferred over
* virt_spin_lock(), virt_spin_lock_key's value is meaningless.
If guest kernel is configured with nopvspin, or guest find its has dedicated pCPUs from realtime hint feature, the pvspinlock will be disabled, and vCPU preemption check is disabled too. but KVM still can emulating HLT for vCPU for both cases, and check if vCPU is preempted or not, and can boost performance Like unixbench, single copy Testcase Base with patch System Benchmarks Index Values INDEX INDEX Dhrystone 2 using register variables 3278.4 3277.7 Double-Precision Whetstone 822.8 825.8 Execl Throughput 1296.5 941.1 File Copy 1024 bufsize 2000 maxblocks 2124.2 2142.7 File Copy 256 bufsize 500 maxblocks 1335.9 1353.6 File Copy 4096 bufsize 8000 maxblocks 4256.3 4760.3 Pipe Throughput 1050.1 1054.0 Pipe-based Context Switching 243.3 352.0 Process Creation 820.1 814.4 Shell Scripts (1 concurrent) 2169.0 2086.0 Shell Scripts (8 concurrent) 7710.3 7576.3 System Call Overhead 672.4 673.9 ======== ======= System Benchmarks Index Score 1467.2 1483.0 Co-developed-by: Wang GuangJu <wangguangju@baidu.com> Signed-off-by: Wang GuangJu <wangguangju@baidu.com> Signed-off-by: Li RongQing <lirongqing@baidu.com> --- arch/x86/kernel/kvm.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-)