Add three log histogram stats to record the distribution of time spent
on successful polling, failed polling and VCPU wait.
halt_poll_success_hist: Distribution of spent time for a successful poll.
halt_poll_fail_hist: Distribution of spent time for a failed poll.
halt_wait_hist: Distribution of time a VCPU has spent on waiting.
Signed-off-by: Jing Zhang <jingzhangos@xxxxxxxxxx>
---
arch/powerpc/kvm/book3s_hv.c | 16 ++++++++++++++--
include/linux/kvm_host.h | 13 ++++++++++++-
include/linux/kvm_types.h | 5 +++++
virt/kvm/kvm_main.c | 12 ++++++++++++
4 files changed, 43 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 92698a5e54fd..c75a5f46d31d 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -4146,17 +4146,29 @@ static void kvmppc_vcore_blocked(struct kvmppc_vcore *vc)
if (do_sleep) {
vc->runner->stat.generic.halt_wait_ns +=
ktime_to_ns(cur) - ktime_to_ns(start_wait);
+ halt_poll_hist_update(
+ vc->runner->stat.generic.halt_wait_hist,
+ ktime_to_ns(cur) - ktime_to_ns(start_wait));
/* Attribute failed poll time */
- if (vc->halt_poll_ns)
+ if (vc->halt_poll_ns) {
vc->runner->stat.generic.halt_poll_fail_ns +=
ktime_to_ns(start_wait) -
ktime_to_ns(start_poll);
+ halt_poll_hist_update(
+ vc->runner->stat.generic.halt_poll_fail_hist,
+ ktime_to_ns(start_wait) -
+ ktime_to_ns(start_poll));
+ }
} else {
/* Attribute successful poll time */
- if (vc->halt_poll_ns)
+ if (vc->halt_poll_ns) {
vc->runner->stat.generic.halt_poll_success_ns +=
ktime_to_ns(cur) -
ktime_to_ns(start_poll);
+ halt_poll_hist_update(
+ vc->runner->stat.generic.halt_poll_success_hist,
+ ktime_to_ns(cur) - ktime_to_ns(start_poll));
+ }
}
/* Adjust poll time */
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 2414f3c7e6f7..e0db0216e627 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1370,7 +1370,13 @@ struct _kvm_stats_desc {
STATS_DESC_COUNTER(VCPU_GENERIC, halt_wakeup), \
STATS_DESC_TIME_NSEC(VCPU_GENERIC, halt_poll_success_ns), \
STATS_DESC_TIME_NSEC(VCPU_GENERIC, halt_poll_fail_ns), \
- STATS_DESC_TIME_NSEC(VCPU_GENERIC, halt_wait_ns)
+ STATS_DESC_TIME_NSEC(VCPU_GENERIC, halt_wait_ns), \
+ STATS_DESC_LOGHIST_TIME_NSEC(VCPU_GENERIC, halt_poll_success_hist, \
+ HALT_POLL_HIST_COUNT), \
+ STATS_DESC_LOGHIST_TIME_NSEC(VCPU_GENERIC, halt_poll_fail_hist, \
+ HALT_POLL_HIST_COUNT), \
+ STATS_DESC_LOGHIST_TIME_NSEC(VCPU_GENERIC, halt_wait_hist, \
+ HALT_POLL_HIST_COUNT)
extern struct dentry *kvm_debugfs_dir;
@@ -1387,6 +1393,11 @@ extern const struct _kvm_stats_desc kvm_vm_stats_desc[];
extern const struct kvm_stats_header kvm_vcpu_stats_header;
extern const struct _kvm_stats_desc kvm_vcpu_stats_desc[];
+static inline void halt_poll_hist_update(u64 *hist, u64 value)
+{
+ kvm_stats_log_hist_update(hist, HALT_POLL_HIST_COUNT, value);
+}
+
#if defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER)
static inline int mmu_notifier_retry(struct kvm *kvm, unsigned long mmu_seq)
{
diff --git a/include/linux/kvm_types.h b/include/linux/kvm_types.h
index d70f8f475da1..e073cfcabf8c 100644
--- a/include/linux/kvm_types.h
+++ b/include/linux/kvm_types.h
@@ -91,6 +91,8 @@ struct kvm_mmu_memory_cache {
#define LOGHIST_BUCKET_COUNT_LARGE 32
#define LOGHIST_BUCKET_COUNT_XLARGE 64
+#define HALT_POLL_HIST_COUNT LOGHIST_BUCKET_COUNT_LARGE
+
struct kvm_vm_stat_generic {
u64 remote_tlb_flush;
};
@@ -103,6 +105,9 @@ struct kvm_vcpu_stat_generic {
u64 halt_poll_success_ns;
u64 halt_poll_fail_ns;
u64 halt_wait_ns;
+ u64 halt_poll_success_hist[HALT_POLL_HIST_COUNT];
+ u64 halt_poll_fail_hist[HALT_POLL_HIST_COUNT];
+ u64 halt_wait_hist[HALT_POLL_HIST_COUNT];
};
#define KVM_STATS_NAME_SIZE 48
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 88bf17e7bf51..5fcdffd7d66a 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -3108,12 +3108,22 @@ void kvm_vcpu_block(struct kvm_vcpu *vcpu)
++vcpu->stat.generic.halt_successful_poll;
if (!vcpu_valid_wakeup(vcpu))
++vcpu->stat.generic.halt_poll_invalid;
+
+ halt_poll_hist_update(
+ vcpu->stat.generic.halt_poll_success_hist,
+ ktime_to_ns(ktime_get()) -
+ ktime_to_ns(start));
goto out;
}
poll_end = cur = ktime_get();
} while (kvm_vcpu_can_poll(cur, stop));
+
+ halt_poll_hist_update(
+ vcpu->stat.generic.halt_poll_fail_hist,
+ ktime_to_ns(ktime_get()) - ktime_to_ns(start));
}
+
prepare_to_rcuwait(&vcpu->wait);
for (;;) {
set_current_state(TASK_INTERRUPTIBLE);
@@ -3129,6 +3139,8 @@ void kvm_vcpu_block(struct kvm_vcpu *vcpu)
if (waited) {
vcpu->stat.generic.halt_wait_ns +=
ktime_to_ns(cur) - ktime_to_ns(poll_end);
+ halt_poll_hist_update(vcpu->stat.generic.halt_wait_hist,
+ ktime_to_ns(cur) - ktime_to_ns(poll_end));
}
out:
kvm_arch_vcpu_unblocking(vcpu);
--
2.32.0.402.g57bb445576-goog
