[PATCH] perf x86 kvm-stat: support to analyze kvm msr

From: Li RongQing
Date: Wed Mar 24 2021 - 23:04:41 EST


From: Lei Zhao <zhaolei27@xxxxxxxxx>

usage:
- kvm stat
run a command and gather performance counter statistics

- show the result:
perf kvm stat report --event=msr

See the msr events:

Analyze events for all VMs, all VCPUs:

MSR Access Samples Samples% Time% Min Time Max Time Avg time

0x6e0:W 67007 98.17% 98.31% 0.59us 10.69us 0.90us ( +- 0.10% )
0x830:W 1186 1.74% 1.60% 0.53us 108.34us 0.82us ( +- 11.02% )
0x3b:R 66 0.10% 0.09% 0.56us 1.26us 0.80us ( +- 3.24% )

Total Samples:68259, Total events handled time:61150.95us.

Signed-off-by: Li RongQing <lirongqing@xxxxxxxxx>
Signed-off-by: Lei Zhao <zhaolei27@xxxxxxxxx>
---
tools/perf/arch/x86/util/kvm-stat.c | 46 +++++++++++++++++++++++++++++
1 file changed, 46 insertions(+)

diff --git a/tools/perf/arch/x86/util/kvm-stat.c b/tools/perf/arch/x86/util/kvm-stat.c
index 072920475b65..c5dd54f6ef5e 100644
--- a/tools/perf/arch/x86/util/kvm-stat.c
+++ b/tools/perf/arch/x86/util/kvm-stat.c
@@ -133,11 +133,56 @@ static struct kvm_events_ops ioport_events = {
.name = "IO Port Access"
};

+ /* The time of emulation msr is from kvm_msr to kvm_entry. */
+static void msr_event_get_key(struct evsel *evsel,
+ struct perf_sample *sample,
+ struct event_key *key)
+{
+ key->key = evsel__intval(evsel, sample, "ecx");
+ key->info = evsel__intval(evsel, sample, "write");
+}
+
+static bool msr_event_begin(struct evsel *evsel,
+ struct perf_sample *sample,
+ struct event_key *key)
+{
+ if (!strcmp(evsel->name, "kvm:kvm_msr")) {
+ msr_event_get_key(evsel, sample, key);
+ return true;
+ }
+
+ return false;
+}
+
+static bool msr_event_end(struct evsel *evsel,
+ struct perf_sample *sample __maybe_unused,
+ struct event_key *key __maybe_unused)
+{
+ return kvm_entry_event(evsel);
+}
+
+static void msr_event_decode_key(struct perf_kvm_stat *kvm __maybe_unused,
+ struct event_key *key,
+ char *decode)
+{
+ scnprintf(decode, decode_str_len, "%#llx:%s",
+ (unsigned long long)key->key,
+ key->info ? "W" : "R");
+}
+
+static struct kvm_events_ops msr_events = {
+ .is_begin_event = msr_event_begin,
+ .is_end_event = msr_event_end,
+ .decode_key = msr_event_decode_key,
+ .name = "MSR Access"
+};
+
const char *kvm_events_tp[] = {
"kvm:kvm_entry",
"kvm:kvm_exit",
"kvm:kvm_mmio",
"kvm:kvm_pio",
+ "kvm:kvm_msr",
NULL,
};

@@ -145,6 +190,7 @@ struct kvm_reg_events_ops kvm_reg_events_ops[] = {
{ .name = "vmexit", .ops = &exit_events },
{ .name = "mmio", .ops = &mmio_events },
{ .name = "ioport", .ops = &ioport_events },
+ { .name = "msr", .ops = &msr_events },
{ NULL, NULL },
};

--
2.17.3