diff mbox series

locking/paravirt: Fix performance regression on core bonded vCPU

Message ID MEYP282MB4026F6DB1A248E9EE7E8BB99C3389@MEYP282MB4026.AUSP282.PROD.OUTLOOK.COM
State New
Headers
Series locking/paravirt: Fix performance regression on core bonded vCPU |

Commit Message

johnnyaiai Nov. 3, 2022, 12:10 p.m. UTC 
  From: johnnyaiai <johnnyaiai@tencent.com>

virt_spin_lock() is preferred over native qspinlock when
vCPU is preempted. But brings a lot of regression while
vCPU is not preempted. Provide a early param 'novirtlock'
to choose would be better.

will-it-scale/lock2_threads -s 10 -t 64
baseline    afterpatch
559938       2166135

Signed-off-by: johnnyaiai <johnnyaiai@tencent.com>
---
 kernel/locking/qspinlock.c | 3 ---
 1 file changed, 3 deletions(-)
diff mbox series

Patch

diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index 59d3d2763..529cf23fe 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -107,6 +107,13 @@  static unsigned paravirt_patch_jmp(void *insn_buff, const void *target,
 
 DEFINE_STATIC_KEY_TRUE(virt_spin_lock_key);
 
+static __init int parse_novirtspin(char *arg)
+{
+	static_branch_disable(&virt_spin_lock_key);
+	return 0;
+}
+early_param("novirtspin", parse_novirtspin);
+
 void __init native_pv_lock_init(void)
 {
 	if (!boot_cpu_has(X86_FEATURE_HYPERVISOR))