diff options
| author | Wanpeng Li <wanpengli@tencent.com> | 2021-04-09 12:18:30 +0800 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2021-04-19 18:04:46 -0400 |
| commit | 4a7132efff1c9f4f80b3cdba75b81c4344e088c2 (patch) | |
| tree | 80f8b15982f871182dde235a6c37937dc23e5371 /arch/x86 | |
| parent | 2b519b5797d432923afaba9522b6b62e13313e4e (diff) | |
KVM: X86: Count attempted/successful directed yield
To analyze some performance issues with lock contention and scheduling,
it is nice to know when directed yield are successful or failing.
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Message-Id: <1617941911-5338-2-git-send-email-wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/include/asm/kvm_host.h | 2 | ||||
| -rw-r--r-- | arch/x86/kvm/x86.c | 24 |
2 files changed, 20 insertions, 6 deletions
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 2f6f4aeca6b7..770063d50142 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1146,6 +1146,8 @@ struct kvm_vcpu_stat { u64 halt_poll_success_ns; u64 halt_poll_fail_ns; u64 nested_run; + u64 directed_yield_attempted; + u64 directed_yield_successful; }; struct x86_instruction_info; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 91c98e71c0e4..05a4bce181d7 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -246,6 +246,8 @@ struct kvm_stats_debugfs_item debugfs_entries[] = { VCPU_STAT("halt_poll_success_ns", halt_poll_success_ns), VCPU_STAT("halt_poll_fail_ns", halt_poll_fail_ns), VCPU_STAT("nested_run", nested_run), + VCPU_STAT("directed_yield_attempted", directed_yield_attempted), + VCPU_STAT("directed_yield_successful", directed_yield_successful), VM_STAT("mmu_shadow_zapped", mmu_shadow_zapped), VM_STAT("mmu_pte_write", mmu_pte_write), VM_STAT("mmu_pde_zapped", mmu_pde_zapped), @@ -8208,21 +8210,31 @@ void kvm_apicv_init(struct kvm *kvm, bool enable) } EXPORT_SYMBOL_GPL(kvm_apicv_init); -static void kvm_sched_yield(struct kvm *kvm, unsigned long dest_id) +static void kvm_sched_yield(struct kvm_vcpu *vcpu, unsigned long dest_id) { struct kvm_vcpu *target = NULL; struct kvm_apic_map *map; + vcpu->stat.directed_yield_attempted++; + rcu_read_lock(); - map = rcu_dereference(kvm->arch.apic_map); + map = rcu_dereference(vcpu->kvm->arch.apic_map); if (likely(map) && dest_id <= map->max_apic_id && map->phys_map[dest_id]) target = map->phys_map[dest_id]->vcpu; rcu_read_unlock(); - if (target && READ_ONCE(target->ready)) - kvm_vcpu_yield_to(target); + if (!target || !READ_ONCE(target->ready)) + goto no_yield; + + if (kvm_vcpu_yield_to(target) <= 0) + goto no_yield; + + vcpu->stat.directed_yield_successful++; + +no_yield: + return; } int kvm_emulate_hypercall(struct kvm_vcpu *vcpu) @@ -8269,7 +8281,7 @@ int kvm_emulate_hypercall(struct kvm_vcpu *vcpu) break; kvm_pv_kick_cpu_op(vcpu->kvm, a0, a1); - kvm_sched_yield(vcpu->kvm, a1); + kvm_sched_yield(vcpu, a1); ret = 0; break; #ifdef CONFIG_X86_64 @@ -8287,7 +8299,7 @@ int kvm_emulate_hypercall(struct kvm_vcpu *vcpu) if (!guest_pv_has(vcpu, KVM_FEATURE_PV_SCHED_YIELD)) break; - kvm_sched_yield(vcpu->kvm, a0); + kvm_sched_yield(vcpu, a0); ret = 0; break; default: |