From 0456ec4ff2b832ab9ff476ed687fea704500f1cd Mon Sep 17 00:00:00 2001 From: Paul Mackerras Date: Fri, 3 Feb 2012 00:56:21 +0000 Subject: KVM: PPC: Book3S HV: Report stolen time to guest through dispatch trace log This adds code to measure "stolen" time per virtual core in units of timebase ticks, and to report the stolen time to the guest using the dispatch trace log (DTL). The guest can register an area of memory for the DTL for a given vcpu. The DTL is a ring buffer where KVM fills in one entry every time it enters the guest for that vcpu. Stolen time is measured as time when the virtual core is not running, either because the vcore is not runnable (e.g. some of its vcpus are executing elsewhere in the kernel or in userspace), or when the vcpu thread that is running the vcore is preempted. This includes time when all the vcpus are idle (i.e. have executed the H_CEDE hypercall), which is OK because the guest accounts stolen time while idle as idle time. Each vcpu keeps a record of how much stolen time has been reported to the guest for that vcpu so far. When we are about to enter the guest, we create a new DTL entry (if the guest vcpu has a DTL) and report the difference between total stolen time for the vcore and stolen time reported so far for the vcpu as the "enqueue to dispatch" time in the DTL entry. Signed-off-by: Paul Mackerras Signed-off-by: Alexander Graf Signed-off-by: Avi Kivity --- arch/powerpc/include/asm/kvm_host.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'arch/powerpc/include') diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h index 93ffd8dd8554..014eaf27a239 100644 --- a/arch/powerpc/include/asm/kvm_host.h +++ b/arch/powerpc/include/asm/kvm_host.h @@ -268,6 +268,9 @@ struct kvmppc_vcore { struct list_head runnable_threads; spinlock_t lock; wait_queue_head_t wq; + u64 stolen_tb; + u64 preempt_tb; + struct kvm_vcpu *runner; }; #define VCORE_ENTRY_COUNT(vc) ((vc)->entry_exit_count & 0xff) @@ -516,6 +519,7 @@ struct kvm_vcpu_arch { struct kvmppc_vpa dtl; struct dtl_entry *dtl_ptr; unsigned long dtl_index; + u64 stolen_logged; struct kvmppc_vpa slb_shadow; #endif }; -- cgit v1.2.3