[PATCH v4 2/2] perf/kvm: Support HCALL events
From: Hemant Kumar <hidden>
Date: 2015-05-21 03:56:26
Also in:
lkml
Subsystem:
performance events subsystem, the rest · Maintainers:
Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo, Namhyung Kim, Linus Torvalds
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 <redacted>
---
Changes:
- Moved the uapi related changes to arch/powerpc side patchset.
This patch has a dependency on :
http://www.mail-archive.com/linuxppc-dev@lists.ozlabs.org/msg89487.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