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Subject[tip:perf/core] perf tools: Add test for converting perf time to/ from TSC
Commit-ID:  3bd5a5fc8c6b9fe769777abf74b0ab5fbd7930b4
Gitweb: http://git.kernel.org/tip/3bd5a5fc8c6b9fe769777abf74b0ab5fbd7930b4
Author: Adrian Hunter <adrian.hunter@intel.com>
AuthorDate: Fri, 28 Jun 2013 16:22:19 +0300
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 23 Jul 2013 12:17:59 +0200

perf tools: Add test for converting perf time to/from TSC

The test uses the newly added cap_usr_time_zero and time_zero of
perf_event_mmap_page. TSC from rdtsc is compared with the time
from 2 perf events. The test passes if the calculated times are
all in the correct order.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1372425741-1676-4-git-send-email-adrian.hunter@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
tools/perf/Makefile | 3 +
tools/perf/arch/x86/Makefile | 2 +
tools/perf/arch/x86/util/tsc.c | 59 ++++++++++++
tools/perf/arch/x86/util/tsc.h | 20 ++++
tools/perf/tests/builtin-test.c | 6 ++
tools/perf/tests/perf-time-to-tsc.c | 177 ++++++++++++++++++++++++++++++++++++
tools/perf/tests/tests.h | 1 +
7 files changed, 268 insertions(+)

diff --git a/tools/perf/Makefile b/tools/perf/Makefile
index 024680b..bfd12d0 100644
--- a/tools/perf/Makefile
+++ b/tools/perf/Makefile
@@ -389,6 +389,9 @@ LIB_OBJS += $(OUTPUT)tests/bp_signal.o
LIB_OBJS += $(OUTPUT)tests/bp_signal_overflow.o
LIB_OBJS += $(OUTPUT)tests/task-exit.o
LIB_OBJS += $(OUTPUT)tests/sw-clock.o
+ifeq ($(ARCH),x86)
+LIB_OBJS += $(OUTPUT)tests/perf-time-to-tsc.o
+endif

BUILTIN_OBJS += $(OUTPUT)builtin-annotate.o
BUILTIN_OBJS += $(OUTPUT)builtin-bench.o
diff --git a/tools/perf/arch/x86/Makefile b/tools/perf/arch/x86/Makefile
index 815841c..8801fe0 100644
--- a/tools/perf/arch/x86/Makefile
+++ b/tools/perf/arch/x86/Makefile
@@ -6,3 +6,5 @@ ifndef NO_LIBUNWIND
LIB_OBJS += $(OUTPUT)arch/$(ARCH)/util/unwind.o
endif
LIB_OBJS += $(OUTPUT)arch/$(ARCH)/util/header.o
+LIB_OBJS += $(OUTPUT)arch/$(ARCH)/util/tsc.o
+LIB_H += arch/$(ARCH)/util/tsc.h
diff --git a/tools/perf/arch/x86/util/tsc.c b/tools/perf/arch/x86/util/tsc.c
new file mode 100644
index 0000000..f111744
--- /dev/null
+++ b/tools/perf/arch/x86/util/tsc.c
@@ -0,0 +1,59 @@
+#include <stdbool.h>
+#include <errno.h>
+
+#include <linux/perf_event.h>
+
+#include "../../perf.h"
+#include "../../util/types.h"
+#include "../../util/debug.h"
+#include "tsc.h"
+
+u64 perf_time_to_tsc(u64 ns, struct perf_tsc_conversion *tc)
+{
+ u64 time, quot, rem;
+
+ time = ns - tc->time_zero;
+ quot = time / tc->time_mult;
+ rem = time % tc->time_mult;
+ return (quot << tc->time_shift) +
+ (rem << tc->time_shift) / tc->time_mult;
+}
+
+u64 tsc_to_perf_time(u64 cyc, struct perf_tsc_conversion *tc)
+{
+ u64 quot, rem;
+
+ quot = cyc >> tc->time_shift;
+ rem = cyc & ((1 << tc->time_shift) - 1);
+ return tc->time_zero + quot * tc->time_mult +
+ ((rem * tc->time_mult) >> tc->time_shift);
+}
+
+int perf_read_tsc_conversion(const struct perf_event_mmap_page *pc,
+ struct perf_tsc_conversion *tc)
+{
+ bool cap_usr_time_zero;
+ u32 seq;
+ int i = 0;
+
+ while (1) {
+ seq = pc->lock;
+ rmb();
+ tc->time_mult = pc->time_mult;
+ tc->time_shift = pc->time_shift;
+ tc->time_zero = pc->time_zero;
+ cap_usr_time_zero = pc->cap_usr_time_zero;
+ rmb();
+ if (pc->lock == seq && !(seq & 1))
+ break;
+ if (++i > 10000) {
+ pr_debug("failed to get perf_event_mmap_page lock\n");
+ return -EINVAL;
+ }
+ }
+
+ if (!cap_usr_time_zero)
+ return -EOPNOTSUPP;
+
+ return 0;
+}
diff --git a/tools/perf/arch/x86/util/tsc.h b/tools/perf/arch/x86/util/tsc.h
new file mode 100644
index 0000000..a24dec8
--- /dev/null
+++ b/tools/perf/arch/x86/util/tsc.h
@@ -0,0 +1,20 @@
+#ifndef TOOLS_PERF_ARCH_X86_UTIL_TSC_H__
+#define TOOLS_PERF_ARCH_X86_UTIL_TSC_H__
+
+#include "../../util/types.h"
+
+struct perf_tsc_conversion {
+ u16 time_shift;
+ u32 time_mult;
+ u64 time_zero;
+};
+
+struct perf_event_mmap_page;
+
+int perf_read_tsc_conversion(const struct perf_event_mmap_page *pc,
+ struct perf_tsc_conversion *tc);
+
+u64 perf_time_to_tsc(u64 ns, struct perf_tsc_conversion *tc);
+u64 tsc_to_perf_time(u64 cyc, struct perf_tsc_conversion *tc);
+
+#endif /* TOOLS_PERF_ARCH_X86_UTIL_TSC_H__ */
diff --git a/tools/perf/tests/builtin-test.c b/tools/perf/tests/builtin-test.c
index 35b45f1466..b7b4049 100644
--- a/tools/perf/tests/builtin-test.c
+++ b/tools/perf/tests/builtin-test.c
@@ -93,6 +93,12 @@ static struct test {
.desc = "Test software clock events have valid period values",
.func = test__sw_clock_freq,
},
+#if defined(__x86_64__) || defined(__i386__)
+ {
+ .desc = "Test converting perf time to TSC",
+ .func = test__perf_time_to_tsc,
+ },
+#endif
{
.func = NULL,
},
diff --git a/tools/perf/tests/perf-time-to-tsc.c b/tools/perf/tests/perf-time-to-tsc.c
new file mode 100644
index 0000000..0ab61b1
--- /dev/null
+++ b/tools/perf/tests/perf-time-to-tsc.c
@@ -0,0 +1,177 @@
+#include <stdio.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <inttypes.h>
+#include <sys/prctl.h>
+
+#include "parse-events.h"
+#include "evlist.h"
+#include "evsel.h"
+#include "thread_map.h"
+#include "cpumap.h"
+#include "tests.h"
+
+#include "../arch/x86/util/tsc.h"
+
+#define CHECK__(x) { \
+ while ((x) < 0) { \
+ pr_debug(#x " failed!\n"); \
+ goto out_err; \
+ } \
+}
+
+#define CHECK_NOT_NULL__(x) { \
+ while ((x) == NULL) { \
+ pr_debug(#x " failed!\n"); \
+ goto out_err; \
+ } \
+}
+
+static u64 rdtsc(void)
+{
+ unsigned int low, high;
+
+ asm volatile("rdtsc" : "=a" (low), "=d" (high));
+
+ return low | ((u64)high) << 32;
+}
+
+/**
+ * test__perf_time_to_tsc - test converting perf time to TSC.
+ *
+ * This function implements a test that checks that the conversion of perf time
+ * to and from TSC is consistent with the order of events. If the test passes
+ * %0 is returned, otherwise %-1 is returned. If TSC conversion is not
+ * supported then then the test passes but " (not supported)" is printed.
+ */
+int test__perf_time_to_tsc(void)
+{
+ struct perf_record_opts opts = {
+ .mmap_pages = UINT_MAX,
+ .user_freq = UINT_MAX,
+ .user_interval = ULLONG_MAX,
+ .freq = 4000,
+ .target = {
+ .uses_mmap = true,
+ },
+ .sample_time = true,
+ };
+ struct thread_map *threads = NULL;
+ struct cpu_map *cpus = NULL;
+ struct perf_evlist *evlist = NULL;
+ struct perf_evsel *evsel = NULL;
+ int err = -1, ret, i;
+ const char *comm1, *comm2;
+ struct perf_tsc_conversion tc;
+ struct perf_event_mmap_page *pc;
+ union perf_event *event;
+ u64 test_tsc, comm1_tsc, comm2_tsc;
+ u64 test_time, comm1_time = 0, comm2_time = 0;
+
+ threads = thread_map__new(-1, getpid(), UINT_MAX);
+ CHECK_NOT_NULL__(threads);
+
+ cpus = cpu_map__new(NULL);
+ CHECK_NOT_NULL__(cpus);
+
+ evlist = perf_evlist__new();
+ CHECK_NOT_NULL__(evlist);
+
+ perf_evlist__set_maps(evlist, cpus, threads);
+
+ CHECK__(parse_events(evlist, "cycles:u"));
+
+ perf_evlist__config(evlist, &opts);
+
+ evsel = perf_evlist__first(evlist);
+
+ evsel->attr.comm = 1;
+ evsel->attr.disabled = 1;
+ evsel->attr.enable_on_exec = 0;
+
+ CHECK__(perf_evlist__open(evlist));
+
+ CHECK__(perf_evlist__mmap(evlist, UINT_MAX, false));
+
+ pc = evlist->mmap[0].base;
+ ret = perf_read_tsc_conversion(pc, &tc);
+ if (ret) {
+ if (ret == -EOPNOTSUPP) {
+ fprintf(stderr, " (not supported)");
+ return 0;
+ }
+ goto out_err;
+ }
+
+ perf_evlist__enable(evlist);
+
+ comm1 = "Test COMM 1";
+ CHECK__(prctl(PR_SET_NAME, (unsigned long)comm1, 0, 0, 0));
+
+ test_tsc = rdtsc();
+
+ comm2 = "Test COMM 2";
+ CHECK__(prctl(PR_SET_NAME, (unsigned long)comm2, 0, 0, 0));
+
+ perf_evlist__disable(evlist);
+
+ for (i = 0; i < evlist->nr_mmaps; i++) {
+ while ((event = perf_evlist__mmap_read(evlist, i)) != NULL) {
+ struct perf_sample sample;
+
+ if (event->header.type != PERF_RECORD_COMM ||
+ (pid_t)event->comm.pid != getpid() ||
+ (pid_t)event->comm.tid != getpid())
+ continue;
+
+ if (strcmp(event->comm.comm, comm1) == 0) {
+ CHECK__(perf_evsel__parse_sample(evsel, event,
+ &sample));
+ comm1_time = sample.time;
+ }
+ if (strcmp(event->comm.comm, comm2) == 0) {
+ CHECK__(perf_evsel__parse_sample(evsel, event,
+ &sample));
+ comm2_time = sample.time;
+ }
+ }
+ }
+
+ if (!comm1_time || !comm2_time)
+ goto out_err;
+
+ test_time = tsc_to_perf_time(test_tsc, &tc);
+ comm1_tsc = perf_time_to_tsc(comm1_time, &tc);
+ comm2_tsc = perf_time_to_tsc(comm2_time, &tc);
+
+ pr_debug("1st event perf time %"PRIu64" tsc %"PRIu64"\n",
+ comm1_time, comm1_tsc);
+ pr_debug("rdtsc time %"PRIu64" tsc %"PRIu64"\n",
+ test_time, test_tsc);
+ pr_debug("2nd event perf time %"PRIu64" tsc %"PRIu64"\n",
+ comm2_time, comm2_tsc);
+
+ if (test_time <= comm1_time ||
+ test_time >= comm2_time)
+ goto out_err;
+
+ if (test_tsc <= comm1_tsc ||
+ test_tsc >= comm2_tsc)
+ goto out_err;
+
+ err = 0;
+
+out_err:
+ if (evlist) {
+ perf_evlist__disable(evlist);
+ perf_evlist__munmap(evlist);
+ perf_evlist__close(evlist);
+ perf_evlist__delete(evlist);
+ }
+ if (cpus)
+ cpu_map__delete(cpus);
+ if (threads)
+ thread_map__delete(threads);
+
+ return err;
+}
diff --git a/tools/perf/tests/tests.h b/tools/perf/tests/tests.h
index 07a92f9..d22202a 100644
--- a/tools/perf/tests/tests.h
+++ b/tools/perf/tests/tests.h
@@ -35,5 +35,6 @@ int test__bp_signal(void);
int test__bp_signal_overflow(void);
int test__task_exit(void);
int test__sw_clock_freq(void);
+int test__perf_time_to_tsc(void);

#endif /* TESTS_H */

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