From 8474e5cac07e7f21dd8c0b3620640db30115db56 Mon Sep 17 00:00:00 2001 From: Christian Borntraeger Date: Fri, 15 Feb 2019 13:47:20 +0100 Subject: KVM: s390: count invalid yields 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 Reviewed-by: David Hildenbrand Reviewed-by: Cornelia Huck --- arch/s390/kvm/diag.c | 18 ++++++++++++++---- arch/s390/kvm/kvm-s390.c | 1 + 2 files changed, 15 insertions(+), 4 deletions(-) (limited to 'arch/s390/kvm') diff --git a/arch/s390/kvm/diag.c b/arch/s390/kvm/diag.c index 45634b3d2e0a..609c55df3ce8 100644 --- a/arch/s390/kvm/diag.c +++ b/arch/s390/kvm/diag.c @@ -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; } diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 40af442b2e15..3b5ebf48f802 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -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) }, -- cgit v1.2.3