From: Srikar Dronamraju <[email protected]>
perf kvm can be used to analyze guest exit reasons. This support already
exists in x86. Hence, porting it to powerpc.
- To trace KVM events :
perf kvm stat record
If many guests are running, we can track for a specific guest by using
--pid as in : perf kvm stat record --pid <pid>
- To see the results :
perf kvm stat report
The result shows the number of exits (from the guest context to
host/hypervisor context) grouped by their respective exit reasons with
their frequency.
This patch makes use of the guest exit reasons available in
"trace_book3s.h". It records on two already available tracepoints :
"kvm_hv:kvm_guest_exit" and "kvm_hv:kvm_guest_enter".
Note : This patch has a dependency on the patch "kvm/powerpc: Export
kvm exit reasons" which exports the KVM exit reasons through the uapi.
Here is a sample o/p:
# pgrep qemu
19378
60515
2 Guests are running on the host.
# perf kvm stat record -a
^C[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 4.153 MB perf.data.guest (39624 samples) ]
# perf kvm stat report -p 60515
Analyze events for pid(s) 60515, all VCPUs:
VM-EXIT Samples Samples% Time% Min Time Max Time Avg time
H_DATA_STORAGE 5006 35.30% 0.13% 1.94us 49.46us 12.37us ( +- 0.52% )
HV_DECREMENTER 4457 31.43% 0.02% 0.72us 16.14us 1.91us ( +- 0.96% )
SYSCALL 2690 18.97% 0.10% 2.84us 528.24us 18.29us ( +- 3.75% )
RETURN_TO_HOST 1789 12.61% 99.76% 1.58us 672791.91us 27470.23us ( +- 3.00% )
EXTERNAL 240 1.69% 0.00% 0.69us 10.67us 1.33us ( +- 5.34% )
Total Samples:14182, Total events handled time:49264158.30us.
Signed-off-by: Srikar Dronamraju <[email protected]>
Signed-off-by: Hemant Kumar <[email protected]>
---
Patch Resend :
- Added few more people to cc list.
- Rebased it to current tip.
Changes :
- Moved the uapi related changes to arch/powerpc patchset.
This patch has a dependency on :
http://www.mail-archive.com/[email protected]/msg90506.html
which exports the kvm exit reasons.
tools/perf/arch/powerpc/Makefile | 1 +
tools/perf/arch/powerpc/util/Build | 1 +
tools/perf/arch/powerpc/util/kvm-stat.c | 33 +++++++++++++++++++++++++++++++++
3 files changed, 35 insertions(+)
create mode 100644 tools/perf/arch/powerpc/util/kvm-stat.c
diff --git a/tools/perf/arch/powerpc/Makefile b/tools/perf/arch/powerpc/Makefile
index 7fbca17..21322e0 100644
--- a/tools/perf/arch/powerpc/Makefile
+++ b/tools/perf/arch/powerpc/Makefile
@@ -1,3 +1,4 @@
ifndef NO_DWARF
PERF_HAVE_DWARF_REGS := 1
endif
+HAVE_KVM_STAT_SUPPORT := 1
diff --git a/tools/perf/arch/powerpc/util/Build b/tools/perf/arch/powerpc/util/Build
index 7b8b0d1..c8fe207 100644
--- a/tools/perf/arch/powerpc/util/Build
+++ b/tools/perf/arch/powerpc/util/Build
@@ -1,5 +1,6 @@
libperf-y += header.o
libperf-y += sym-handling.o
+libperf-y += kvm-stat.o
libperf-$(CONFIG_DWARF) += dwarf-regs.o
libperf-$(CONFIG_DWARF) += skip-callchain-idx.o
diff --git a/tools/perf/arch/powerpc/util/kvm-stat.c b/tools/perf/arch/powerpc/util/kvm-stat.c
new file mode 100644
index 0000000..24e06bf
--- /dev/null
+++ b/tools/perf/arch/powerpc/util/kvm-stat.c
@@ -0,0 +1,33 @@
+#include "../../util/kvm-stat.h"
+#include <asm/kvm_perf_book3s.h>
+
+define_exit_reasons_table(hv_exit_reasons, kvm_trace_symbol_exit);
+
+static struct kvm_events_ops exit_events = {
+ .is_begin_event = exit_event_begin,
+ .is_end_event = exit_event_end,
+ .decode_key = exit_event_decode_key,
+ .name = "VM-EXIT"
+};
+
+const char *const kvm_events_tp[] = {
+ "kvm_hv:kvm_guest_exit",
+ "kvm_hv:kvm_guest_enter",
+ NULL,
+};
+
+struct kvm_reg_events_ops kvm_reg_events_ops[] = {
+ { .name = "vmexit", .ops = &exit_events },
+ { NULL, NULL },
+};
+
+const char * const kvm_skip_events[] = {
+ NULL,
+};
+
+int cpu_isa_init(struct perf_kvm_stat *kvm, const char *cpuid __maybe_unused)
+{
+ kvm->exit_reasons = hv_exit_reasons;
+ kvm->exit_reasons_isa = "HV";
+ return 0;
+}
--
1.9.3
powerpc provides hcall events that also provides insights into guest
behaviour. Enhance perf kvm to record and analyze hcall events.
- To trace hcall events :
perf kvm stat record
- To show the results :
perf kvm stat report --event=hcall
The result shows the number of hypervisor calls from the guest grouped
by their respective reasons displayed with the frequency.
This patch makes use of two additional tracepoints
"kvm_hv:kvm_hcall_enter" and "kvm_hv:kvm_hcall_exit". It uses the
pSeries hypervisor codes exported through uapi to classify the hcalls
into their respective reasons.
Note : This patch has a dependency on "kvm/powerpc: Export HCALL reason
codes" which exports HCALL reasons through uapi.
# pgrep qemu
A sample output :
19378
60515
2 VMs running.
# perf kvm stat record -a
^C[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 4.153 MB perf.data.guest (39624 samples) ]
# perf kvm stat report -p 60515 --event=hcall
Analyze events for pid(s) 60515, all VCPUs:
HCALL-EVENT Samples Samples% Time% Min Time Max Time Avg time
H_VIO_SIGNAL 1034 38.44% 15.77% 0.36us 1.59us 0.44us ( +- 0.66% )
H_SEND_CRQ 652 24.24% 10.97% 0.39us 1.84us 0.49us ( +- 1.20% )
H_IPI 523 19.44% 62.05% 1.35us 19.70us 3.44us ( +- 2.88% )
H_PUT_TERM_CHAR 411 15.28% 8.03% 0.38us 3.77us 0.57us ( +- 1.61% )
H_GET_TERM_CHAR 50 1.86% 0.99% 0.40us 0.98us 0.57us ( +- 3.37% )
H_EOI 20 0.74% 2.19% 2.22us 4.72us 3.17us ( +- 5.96% )
Total Samples:2690, Total events handled time:2896.94us.
Signed-off-by: Hemant Kumar <[email protected]>
---
Changes:
- Moved the uapi related changes to arch/powerpc side patchset.
This patch has a dependency on :
http://www.mail-archive.com/[email protected]/msg90507.html
which export hcall reasons through uapi.
tools/perf/arch/powerpc/util/kvm-stat.c | 61 +++++++++++++++++++++++++++++++++
1 file changed, 61 insertions(+)
diff --git a/tools/perf/arch/powerpc/util/kvm-stat.c b/tools/perf/arch/powerpc/util/kvm-stat.c
index 24e06bf..0d3ea47 100644
--- a/tools/perf/arch/powerpc/util/kvm-stat.c
+++ b/tools/perf/arch/powerpc/util/kvm-stat.c
@@ -1,7 +1,9 @@
#include "../../util/kvm-stat.h"
#include <asm/kvm_perf_book3s.h>
+#include "../../util/debug.h"
define_exit_reasons_table(hv_exit_reasons, kvm_trace_symbol_exit);
+define_exit_reasons_table(hcall_reasons, kvm_trace_symbol_hcall);
static struct kvm_events_ops exit_events = {
.is_begin_event = exit_event_begin,
@@ -10,14 +12,73 @@ static struct kvm_events_ops exit_events = {
.name = "VM-EXIT"
};
+static void hcall_event_get_key(struct perf_evsel *evsel,
+ struct perf_sample *sample,
+ struct event_key *key)
+{
+ key->info = 0;
+ key->key = perf_evsel__intval(evsel, sample, KVM_HCALL_REASON);
+}
+
+static const char *get_exit_reason(u64 exit_code)
+{
+ struct exit_reasons_table *tbl = hcall_reasons;
+
+ while (tbl->reason != NULL) {
+ if (tbl->exit_code == exit_code)
+ return tbl->reason;
+ tbl++;
+ }
+
+ pr_err("Unknown kvm hcall exit code: %lld\n",
+ (unsigned long long)exit_code);
+ return "UNKNOWN";
+}
+
+static bool hcall_event_end(struct perf_evsel *evsel,
+ struct perf_sample *sample __maybe_unused,
+ struct event_key *key __maybe_unused)
+{
+ return (!strcmp(evsel->name, KVM_HCALL_EXIT_TRACE));
+}
+
+static bool hcall_event_begin(struct perf_evsel *evsel,
+ struct perf_sample *sample, struct event_key *key)
+{
+ if (!strcmp(evsel->name, KVM_HCALL_ENTRY_TRACE)) {
+ hcall_event_get_key(evsel, sample, key);
+ return true;
+ }
+
+ return false;
+}
+static void hcall_event_decode_key(struct perf_kvm_stat *kvm __maybe_unused,
+ struct event_key *key,
+ char *decode)
+{
+ const char *hcall_reason = get_exit_reason(key->key);
+
+ scnprintf(decode, DECODE_STR_LEN, "%s", hcall_reason);
+}
+
+static struct kvm_events_ops hcall_events = {
+ .is_begin_event = hcall_event_begin,
+ .is_end_event = hcall_event_end,
+ .decode_key = hcall_event_decode_key,
+ .name = "HCALL-EVENT",
+};
+
const char *const kvm_events_tp[] = {
"kvm_hv:kvm_guest_exit",
"kvm_hv:kvm_guest_enter",
+ "kvm_hv:kvm_hcall_enter",
+ "kvm_hv:kvm_hcall_exit",
NULL,
};
struct kvm_reg_events_ops kvm_reg_events_ops[] = {
{ .name = "vmexit", .ops = &exit_events },
+ { .name = "hcall", .ops = &hcall_events },
{ NULL, NULL },
};
--
1.9.3