[PATCH v7 3/3] KVM: trace kvm_halt_poll_ns grow/shrink

From: Wanpeng Li
Date: Thu Sep 03 2015 - 20:11:42 EST


Tracepoint for dynamic halt_pool_ns, fired on every potential change.

Signed-off-by: Wanpeng Li <wanpeng.li@xxxxxxxxxxx>
---
include/trace/events/kvm.h | 30 ++++++++++++++++++++++++++++++
virt/kvm/kvm_main.c | 8 ++++++--
2 files changed, 36 insertions(+), 2 deletions(-)

diff --git a/include/trace/events/kvm.h b/include/trace/events/kvm.h
index a44062d..0d1bc47 100644
--- a/include/trace/events/kvm.h
+++ b/include/trace/events/kvm.h
@@ -356,6 +356,36 @@ TRACE_EVENT(
__entry->address)
);

+TRACE_EVENT(kvm_halt_poll_ns,
+ TP_PROTO(bool grow, unsigned int vcpu_id, int new, int old),
+ TP_ARGS(grow, vcpu_id, new, old),
+
+ TP_STRUCT__entry(
+ __field(bool, grow)
+ __field(unsigned int, vcpu_id)
+ __field(int, new)
+ __field(int, old)
+ ),
+
+ TP_fast_assign(
+ __entry->grow = grow;
+ __entry->vcpu_id = vcpu_id;
+ __entry->new = new;
+ __entry->old = old;
+ ),
+
+ TP_printk("vcpu %u: halt_poll_ns %d (%s %d)",
+ __entry->vcpu_id,
+ __entry->new,
+ __entry->grow ? "grow" : "shrink",
+ __entry->old)
+);
+
+#define trace_kvm_halt_poll_ns_grow(vcpu_id, new, old) \
+ trace_kvm_halt_poll_ns(true, vcpu_id, new, old)
+#define trace_kvm_halt_poll_ns_shrink(vcpu_id, new, old) \
+ trace_kvm_halt_poll_ns(false, vcpu_id, new, old)
+
#endif

#endif /* _TRACE_KVM_MAIN_H */
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index d5e07e9..44a1301 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1918,8 +1918,9 @@ EXPORT_SYMBOL_GPL(kvm_vcpu_mark_page_dirty);

static void grow_halt_poll_ns(struct kvm_vcpu *vcpu)
{
- int val = vcpu->halt_poll_ns;
+ int old, val;

+ old = val = vcpu->halt_poll_ns;
/* 10us base */
if (val == 0 && halt_poll_ns_grow)
val = 10000;
@@ -1927,18 +1928,21 @@ static void grow_halt_poll_ns(struct kvm_vcpu *vcpu)
val *= halt_poll_ns_grow;

vcpu->halt_poll_ns = val;
+ trace_kvm_halt_poll_ns_grow(vcpu->vcpu_id, val, old);
}

static void shrink_halt_poll_ns(struct kvm_vcpu *vcpu)
{
- int val = vcpu->halt_poll_ns;
+ int old, val;

+ old = val = vcpu->halt_poll_ns;
if (halt_poll_ns_shrink == 0)
val = 0;
else
val /= halt_poll_ns_shrink;

vcpu->halt_poll_ns = val;
+ trace_kvm_halt_poll_ns_shrink(vcpu->vcpu_id, val, old);
}

static int kvm_vcpu_check_block(struct kvm_vcpu *vcpu)
--
1.9.1

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