perf-time-to-tsc.c
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#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 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())
goto next_event;
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;
}
next_event:
perf_evlist__mmap_consume(evlist, i);
}
}
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__delete(evlist);
}
return err;
}