KVM: ppc: Implement in-kernel exit timing statistics
Existing KVM statistics are either just counters (kvm_stat) reported for
KVM generally or trace based aproaches like kvm_trace.
For KVM on powerpc we had the need to track the timings of the different exit
types. While this could be achieved parsing data created with a kvm_trace
extension this adds too much overhead (at least on embedded PowerPC) slowing
down the workloads we wanted to measure.
Therefore this patch adds a in-kernel exit timing statistic to the powerpc kvm
code. These statistic is available per vm&vcpu under the kvm debugfs directory.
As this statistic is low, but still some overhead it can be enabled via a
.config entry and should be off by default.
Since this patch touched all powerpc kvm_stat code anyway this code is now
merged and simplified together with the exit timing statistic code (still
working with exit timing disabled in .config).
Signed-off-by: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
Signed-off-by: Hollis Blanchard <hollisb@us.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index a4a7d5e..2f5b49f 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -71,6 +71,49 @@
u32 word2;
};
+enum kvm_exit_types {
+ MMIO_EXITS,
+ DCR_EXITS,
+ SIGNAL_EXITS,
+ ITLB_REAL_MISS_EXITS,
+ ITLB_VIRT_MISS_EXITS,
+ DTLB_REAL_MISS_EXITS,
+ DTLB_VIRT_MISS_EXITS,
+ SYSCALL_EXITS,
+ ISI_EXITS,
+ DSI_EXITS,
+ EMULATED_INST_EXITS,
+ EMULATED_MTMSRWE_EXITS,
+ EMULATED_WRTEE_EXITS,
+ EMULATED_MTSPR_EXITS,
+ EMULATED_MFSPR_EXITS,
+ EMULATED_MTMSR_EXITS,
+ EMULATED_MFMSR_EXITS,
+ EMULATED_TLBSX_EXITS,
+ EMULATED_TLBWE_EXITS,
+ EMULATED_RFI_EXITS,
+ DEC_EXITS,
+ EXT_INTR_EXITS,
+ HALT_WAKEUP,
+ USR_PR_INST,
+ FP_UNAVAIL,
+ DEBUG_EXITS,
+ TIMEINGUEST,
+ __NUMBER_OF_KVM_EXIT_TYPES
+};
+
+#ifdef CONFIG_KVM_EXIT_TIMING
+/* allow access to big endian 32bit upper/lower parts and 64bit var */
+struct exit_timing {
+ union {
+ u64 tv64;
+ struct {
+ u32 tbu, tbl;
+ } tv32;
+ };
+};
+#endif
+
struct kvm_arch {
};
@@ -130,6 +173,19 @@
u32 dbcr0;
u32 dbcr1;
+#ifdef CONFIG_KVM_EXIT_TIMING
+ struct exit_timing timing_exit;
+ struct exit_timing timing_last_enter;
+ u32 last_exit_type;
+ u32 timing_count_type[__NUMBER_OF_KVM_EXIT_TYPES];
+ u64 timing_sum_duration[__NUMBER_OF_KVM_EXIT_TYPES];
+ u64 timing_sum_quad_duration[__NUMBER_OF_KVM_EXIT_TYPES];
+ u64 timing_min_duration[__NUMBER_OF_KVM_EXIT_TYPES];
+ u64 timing_max_duration[__NUMBER_OF_KVM_EXIT_TYPES];
+ u64 timing_last_exit;
+ struct dentry *debugfs_exit_timing;
+#endif
+
u32 last_inst;
ulong fault_dear;
ulong fault_esr;