SCHEDSTATS provide a precise source of information about time tasks
spent on a runqueue, but not running (among other things). It is
specially useful for the steal time implementation, because it doesn't
record halt time at all.
To avoid a hard dependency on schedstats, since it is possible one won't
want to record statistics about all processes running, the previous method
of time measurement on put/load vcpu is kept for !SCHEDSTATS.
Signed-off-by: Glauber Costa <glommer@xxxxxxxxxx>
CC: Rik van Riel <riel@xxxxxxxxxx>
CC: Jeremy Fitzhardinge <jeremy.fitzhardinge@xxxxxxxxxx>
CC: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CC: Avi Kivity <avi@xxxxxxxxxx>
CC: Anthony Liguori <aliguori@xxxxxxxxxx>
CC: Eric B Munson <emunson@xxxxxxxxx>
CC: Marcelo Tosatti <mtosatti@xxxxxxxxxx>
---
arch/x86/kvm/x86.c | 22 ++++++++++++++++++----
1 files changed, 18 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index df9d274..7e87159 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1502,7 +1502,13 @@ static void record_steal_time(struct kvm_vcpu *vcpu)
&vcpu->arch.st.steal, sizeof(struct kvm_steal_time))))
return;
- delta = (get_kernel_ns() - vcpu->arch.st.this_time_out);
+#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
+ if (likely(sched_info_on())) {
+ delta = current->sched_info.run_delay - vcpu->arch.st.this_time_out;
+ vcpu->arch.st.this_time_out = current->sched_info.run_delay;
+ } else
+#endif
+ delta = (get_kernel_ns() - vcpu->arch.st.this_time_out);
vcpu->arch.st.steal.steal += delta;
vcpu->arch.st.steal.version += 2;
@@ -1607,9 +1613,14 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 data)
data & KVM_STEAL_VALID_BITS))
return 1;
- vcpu->arch.st.this_time_out = get_kernel_ns();
- record_steal_time(vcpu);
+#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
+ if (likely(sched_info_on()))
+ vcpu->arch.st.this_time_out = current->sched_info.run_delay;
+ else
+#endif
+ vcpu->arch.st.this_time_out = get_kernel_ns();
+ record_steal_time(vcpu);
break;
case MSR_IA32_MCG_CTL:
@@ -2220,7 +2231,10 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
kvm_x86_ops->vcpu_put(vcpu);
kvm_put_guest_fpu(vcpu);
kvm_get_msr(vcpu, MSR_IA32_TSC, &vcpu->arch.last_guest_tsc);
- vcpu->arch.st.this_time_out = get_kernel_ns();
+#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
+ if (unlikely(!sched_info_on()))
+#endif
+ vcpu->arch.st.this_time_out = get_kernel_ns();
}
static int is_efer_nx(void)
--
1.7.3.4
--
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