redonkable/alistair23-linux
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KVM: s390: count invalid yields

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To analyze some performance issues with lock contention and scheduling
it is nice to know when diag9c did not result in any action or when
no action was tried.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
This commit is contained in:
Christian Borntraeger 2019-02-15 13:47:20 +01:00
parent efec8d219f
commit 8474e5cac0
3 changed files with 16 additions and 4 deletions
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1
arch/s390/include/asm/kvm_host.h
View file

@ -392,6 +392,7 @@ struct kvm_vcpu_stat {
u64 diagnose_10;
u64 diagnose_44;
u64 diagnose_9c;
u64 diagnose_9c_ignored;
u64 diagnose_258;
u64 diagnose_308;
u64 diagnose_500;

18
arch/s390/kvm/diag.c
View file

@ -158,14 +158,24 @@ static int __diag_time_slice_end_directed(struct kvm_vcpu *vcpu)
tid = vcpu->run->s.regs.gprs[(vcpu->arch.sie_block->ipa & 0xf0) >> 4];
vcpu->stat.diagnose_9c++;
VCPU_EVENT(vcpu, 5, "diag time slice end directed to %d", tid);
/* yield to self */
if (tid == vcpu->vcpu_id)
return 0;
goto no_yield;
/* yield to invalid */
tcpu = kvm_get_vcpu_by_id(vcpu->kvm, tid);
if (tcpu)
kvm_vcpu_yield_to(tcpu);
if (!tcpu)
goto no_yield;
if (kvm_vcpu_yield_to(tcpu) <= 0)
goto no_yield;
VCPU_EVENT(vcpu, 5, "diag time slice end directed to %d: done", tid);
return 0;
no_yield:
VCPU_EVENT(vcpu, 5, "diag time slice end directed to %d: ignored", tid);
vcpu->stat.diagnose_9c_ignored++;
return 0;
}

1
arch/s390/kvm/kvm-s390.c
View file

@ -155,6 +155,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = {
{ "instruction_diag_10", VCPU_STAT(diagnose_10) },
{ "instruction_diag_44", VCPU_STAT(diagnose_44) },
{ "instruction_diag_9c", VCPU_STAT(diagnose_9c) },
{ "diag_9c_ignored", VCPU_STAT(diagnose_9c_ignored) },
{ "instruction_diag_258", VCPU_STAT(diagnose_258) },
{ "instruction_diag_308", VCPU_STAT(diagnose_308) },
{ "instruction_diag_500", VCPU_STAT(diagnose_500) },