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linux-next/tools/perf/tests/code-reading.c
Arnaldo Carvalho de Melo 5243ba76a5 perf test: Reduce the sample_freq for the 'object code reading' test
Using 4 kHz is not necessary and sometimes is more than what was
auto-tuned:

  # dmesg | grep max_sample_rate | tail -2
  [ 2499.144373] perf interrupt took too long (2501 > 2500), lowering kernel.perf_event_max_sample_rate to 50000
  [ 3592.413606] perf interrupt took too long (5069 > 5000), lowering kernel.perf_event_max_sample_rate to 25000

Simulating a auto-tune of 2000 we make the test fail, as reported
by Steven Noonan for one of his machines, so reduce it to 500 HZ,
it is enough to get a good number of samples for this test:

  # perf test -v 21 2>&1  | grep '^Reading object code for memory address' | tee /tmp/out | tail -5
  Reading object code for memory address: 0x479f40
  Reading object code for memory address: 0x7f29b7eea80d
  Reading object code for memory address: 0x7f29b7eea80d
  Reading object code for memory address: 0x7f29b7eea800
  Reading object code for memory address: 0xffffffff813b2f23
  [root@jouet ~]# wc -l /tmp/out
  40 /tmp/out
  [root@jouet ~]#

For systems that auto-tune below that, the previous patches will tell the
user what is happening so that he may either ignore the result of this test or
bump /proc/sys/kernel/perf_event_max_sample_rate.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Steven Noonan <steven@uplinklabs.net>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-6kufyy1iprdfzrbtuqgxir70@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2016-02-19 19:12:44 -03:00

641 lines
13 KiB
C

#include <linux/types.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include "parse-events.h"
#include "evlist.h"
#include "evsel.h"
#include "thread_map.h"
#include "cpumap.h"
#include "machine.h"
#include "event.h"
#include "thread.h"
#include "tests.h"
#define BUFSZ 1024
#define READLEN 128
struct state {
u64 done[1024];
size_t done_cnt;
};
static unsigned int hex(char c)
{
if (c >= '0' && c <= '9')
return c - '0';
if (c >= 'a' && c <= 'f')
return c - 'a' + 10;
return c - 'A' + 10;
}
static size_t read_objdump_line(const char *line, size_t line_len, void *buf,
size_t len)
{
const char *p;
size_t i, j = 0;
/* Skip to a colon */
p = strchr(line, ':');
if (!p)
return 0;
i = p + 1 - line;
/* Read bytes */
while (j < len) {
char c1, c2;
/* Skip spaces */
for (; i < line_len; i++) {
if (!isspace(line[i]))
break;
}
/* Get 2 hex digits */
if (i >= line_len || !isxdigit(line[i]))
break;
c1 = line[i++];
if (i >= line_len || !isxdigit(line[i]))
break;
c2 = line[i++];
/* Followed by a space */
if (i < line_len && line[i] && !isspace(line[i]))
break;
/* Store byte */
*(unsigned char *)buf = (hex(c1) << 4) | hex(c2);
buf += 1;
j++;
}
/* return number of successfully read bytes */
return j;
}
static int read_objdump_output(FILE *f, void *buf, size_t *len, u64 start_addr)
{
char *line = NULL;
size_t line_len, off_last = 0;
ssize_t ret;
int err = 0;
u64 addr, last_addr = start_addr;
while (off_last < *len) {
size_t off, read_bytes, written_bytes;
unsigned char tmp[BUFSZ];
ret = getline(&line, &line_len, f);
if (feof(f))
break;
if (ret < 0) {
pr_debug("getline failed\n");
err = -1;
break;
}
/* read objdump data into temporary buffer */
read_bytes = read_objdump_line(line, ret, tmp, sizeof(tmp));
if (!read_bytes)
continue;
if (sscanf(line, "%"PRIx64, &addr) != 1)
continue;
if (addr < last_addr) {
pr_debug("addr going backwards, read beyond section?\n");
break;
}
last_addr = addr;
/* copy it from temporary buffer to 'buf' according
* to address on current objdump line */
off = addr - start_addr;
if (off >= *len)
break;
written_bytes = MIN(read_bytes, *len - off);
memcpy(buf + off, tmp, written_bytes);
off_last = off + written_bytes;
}
/* len returns number of bytes that could not be read */
*len -= off_last;
free(line);
return err;
}
static int read_via_objdump(const char *filename, u64 addr, void *buf,
size_t len)
{
char cmd[PATH_MAX * 2];
const char *fmt;
FILE *f;
int ret;
fmt = "%s -z -d --start-address=0x%"PRIx64" --stop-address=0x%"PRIx64" %s";
ret = snprintf(cmd, sizeof(cmd), fmt, "objdump", addr, addr + len,
filename);
if (ret <= 0 || (size_t)ret >= sizeof(cmd))
return -1;
pr_debug("Objdump command is: %s\n", cmd);
/* Ignore objdump errors */
strcat(cmd, " 2>/dev/null");
f = popen(cmd, "r");
if (!f) {
pr_debug("popen failed\n");
return -1;
}
ret = read_objdump_output(f, buf, &len, addr);
if (len) {
pr_debug("objdump read too few bytes\n");
if (!ret)
ret = len;
}
pclose(f);
return ret;
}
static void dump_buf(unsigned char *buf, size_t len)
{
size_t i;
for (i = 0; i < len; i++) {
pr_debug("0x%02x ", buf[i]);
if (i % 16 == 15)
pr_debug("\n");
}
pr_debug("\n");
}
static int read_object_code(u64 addr, size_t len, u8 cpumode,
struct thread *thread, struct state *state)
{
struct addr_location al;
unsigned char buf1[BUFSZ];
unsigned char buf2[BUFSZ];
size_t ret_len;
u64 objdump_addr;
int ret;
pr_debug("Reading object code for memory address: %#"PRIx64"\n", addr);
thread__find_addr_map(thread, cpumode, MAP__FUNCTION, addr, &al);
if (!al.map || !al.map->dso) {
pr_debug("thread__find_addr_map failed\n");
return -1;
}
pr_debug("File is: %s\n", al.map->dso->long_name);
if (al.map->dso->symtab_type == DSO_BINARY_TYPE__KALLSYMS &&
!dso__is_kcore(al.map->dso)) {
pr_debug("Unexpected kernel address - skipping\n");
return 0;
}
pr_debug("On file address is: %#"PRIx64"\n", al.addr);
if (len > BUFSZ)
len = BUFSZ;
/* Do not go off the map */
if (addr + len > al.map->end)
len = al.map->end - addr;
/* Read the object code using perf */
ret_len = dso__data_read_offset(al.map->dso, thread->mg->machine,
al.addr, buf1, len);
if (ret_len != len) {
pr_debug("dso__data_read_offset failed\n");
return -1;
}
/*
* Converting addresses for use by objdump requires more information.
* map__load() does that. See map__rip_2objdump() for details.
*/
if (map__load(al.map, NULL))
return -1;
/* objdump struggles with kcore - try each map only once */
if (dso__is_kcore(al.map->dso)) {
size_t d;
for (d = 0; d < state->done_cnt; d++) {
if (state->done[d] == al.map->start) {
pr_debug("kcore map tested already");
pr_debug(" - skipping\n");
return 0;
}
}
if (state->done_cnt >= ARRAY_SIZE(state->done)) {
pr_debug("Too many kcore maps - skipping\n");
return 0;
}
state->done[state->done_cnt++] = al.map->start;
}
/* Read the object code using objdump */
objdump_addr = map__rip_2objdump(al.map, al.addr);
ret = read_via_objdump(al.map->dso->long_name, objdump_addr, buf2, len);
if (ret > 0) {
/*
* The kernel maps are inaccurate - assume objdump is right in
* that case.
*/
if (cpumode == PERF_RECORD_MISC_KERNEL ||
cpumode == PERF_RECORD_MISC_GUEST_KERNEL) {
len -= ret;
if (len) {
pr_debug("Reducing len to %zu\n", len);
} else if (dso__is_kcore(al.map->dso)) {
/*
* objdump cannot handle very large segments
* that may be found in kcore.
*/
pr_debug("objdump failed for kcore");
pr_debug(" - skipping\n");
return 0;
} else {
return -1;
}
}
}
if (ret < 0) {
pr_debug("read_via_objdump failed\n");
return -1;
}
/* The results should be identical */
if (memcmp(buf1, buf2, len)) {
pr_debug("Bytes read differ from those read by objdump\n");
pr_debug("buf1 (dso):\n");
dump_buf(buf1, len);
pr_debug("buf2 (objdump):\n");
dump_buf(buf2, len);
return -1;
}
pr_debug("Bytes read match those read by objdump\n");
return 0;
}
static int process_sample_event(struct machine *machine,
struct perf_evlist *evlist,
union perf_event *event, struct state *state)
{
struct perf_sample sample;
struct thread *thread;
u8 cpumode;
int ret;
if (perf_evlist__parse_sample(evlist, event, &sample)) {
pr_debug("perf_evlist__parse_sample failed\n");
return -1;
}
thread = machine__findnew_thread(machine, sample.pid, sample.tid);
if (!thread) {
pr_debug("machine__findnew_thread failed\n");
return -1;
}
cpumode = event->header.misc & PERF_RECORD_MISC_CPUMODE_MASK;
ret = read_object_code(sample.ip, READLEN, cpumode, thread, state);
thread__put(thread);
return ret;
}
static int process_event(struct machine *machine, struct perf_evlist *evlist,
union perf_event *event, struct state *state)
{
if (event->header.type == PERF_RECORD_SAMPLE)
return process_sample_event(machine, evlist, event, state);
if (event->header.type == PERF_RECORD_THROTTLE ||
event->header.type == PERF_RECORD_UNTHROTTLE)
return 0;
if (event->header.type < PERF_RECORD_MAX) {
int ret;
ret = machine__process_event(machine, event, NULL);
if (ret < 0)
pr_debug("machine__process_event failed, event type %u\n",
event->header.type);
return ret;
}
return 0;
}
static int process_events(struct machine *machine, struct perf_evlist *evlist,
struct state *state)
{
union perf_event *event;
int i, ret;
for (i = 0; i < evlist->nr_mmaps; i++) {
while ((event = perf_evlist__mmap_read(evlist, i)) != NULL) {
ret = process_event(machine, evlist, event, state);
perf_evlist__mmap_consume(evlist, i);
if (ret < 0)
return ret;
}
}
return 0;
}
static int comp(const void *a, const void *b)
{
return *(int *)a - *(int *)b;
}
static void do_sort_something(void)
{
int buf[40960], i;
for (i = 0; i < (int)ARRAY_SIZE(buf); i++)
buf[i] = ARRAY_SIZE(buf) - i - 1;
qsort(buf, ARRAY_SIZE(buf), sizeof(int), comp);
for (i = 0; i < (int)ARRAY_SIZE(buf); i++) {
if (buf[i] != i) {
pr_debug("qsort failed\n");
break;
}
}
}
static void sort_something(void)
{
int i;
for (i = 0; i < 10; i++)
do_sort_something();
}
static void syscall_something(void)
{
int pipefd[2];
int i;
for (i = 0; i < 1000; i++) {
if (pipe(pipefd) < 0) {
pr_debug("pipe failed\n");
break;
}
close(pipefd[1]);
close(pipefd[0]);
}
}
static void fs_something(void)
{
const char *test_file_name = "temp-perf-code-reading-test-file--";
FILE *f;
int i;
for (i = 0; i < 1000; i++) {
f = fopen(test_file_name, "w+");
if (f) {
fclose(f);
unlink(test_file_name);
}
}
}
static void do_something(void)
{
fs_something();
sort_something();
syscall_something();
}
enum {
TEST_CODE_READING_OK,
TEST_CODE_READING_NO_VMLINUX,
TEST_CODE_READING_NO_KCORE,
TEST_CODE_READING_NO_ACCESS,
TEST_CODE_READING_NO_KERNEL_OBJ,
};
static int do_test_code_reading(bool try_kcore)
{
struct machine *machine;
struct thread *thread;
struct record_opts opts = {
.mmap_pages = UINT_MAX,
.user_freq = UINT_MAX,
.user_interval = ULLONG_MAX,
.freq = 500,
.target = {
.uses_mmap = true,
},
};
struct state state = {
.done_cnt = 0,
};
struct thread_map *threads = NULL;
struct cpu_map *cpus = NULL;
struct perf_evlist *evlist = NULL;
struct perf_evsel *evsel = NULL;
int err = -1, ret;
pid_t pid;
struct map *map;
bool have_vmlinux, have_kcore, excl_kernel = false;
pid = getpid();
machine = machine__new_host();
ret = machine__create_kernel_maps(machine);
if (ret < 0) {
pr_debug("machine__create_kernel_maps failed\n");
goto out_err;
}
/* Force the use of kallsyms instead of vmlinux to try kcore */
if (try_kcore)
symbol_conf.kallsyms_name = "/proc/kallsyms";
/* Load kernel map */
map = machine__kernel_map(machine);
ret = map__load(map, NULL);
if (ret < 0) {
pr_debug("map__load failed\n");
goto out_err;
}
have_vmlinux = dso__is_vmlinux(map->dso);
have_kcore = dso__is_kcore(map->dso);
/* 2nd time through we just try kcore */
if (try_kcore && !have_kcore)
return TEST_CODE_READING_NO_KCORE;
/* No point getting kernel events if there is no kernel object */
if (!have_vmlinux && !have_kcore)
excl_kernel = true;
threads = thread_map__new_by_tid(pid);
if (!threads) {
pr_debug("thread_map__new_by_tid failed\n");
goto out_err;
}
ret = perf_event__synthesize_thread_map(NULL, threads,
perf_event__process, machine, false, 500);
if (ret < 0) {
pr_debug("perf_event__synthesize_thread_map failed\n");
goto out_err;
}
thread = machine__findnew_thread(machine, pid, pid);
if (!thread) {
pr_debug("machine__findnew_thread failed\n");
goto out_put;
}
cpus = cpu_map__new(NULL);
if (!cpus) {
pr_debug("cpu_map__new failed\n");
goto out_put;
}
while (1) {
const char *str;
evlist = perf_evlist__new();
if (!evlist) {
pr_debug("perf_evlist__new failed\n");
goto out_put;
}
perf_evlist__set_maps(evlist, cpus, threads);
if (excl_kernel)
str = "cycles:u";
else
str = "cycles";
pr_debug("Parsing event '%s'\n", str);
ret = parse_events(evlist, str, NULL);
if (ret < 0) {
pr_debug("parse_events failed\n");
goto out_put;
}
perf_evlist__config(evlist, &opts);
evsel = perf_evlist__first(evlist);
evsel->attr.comm = 1;
evsel->attr.disabled = 1;
evsel->attr.enable_on_exec = 0;
ret = perf_evlist__open(evlist);
if (ret < 0) {
if (!excl_kernel) {
excl_kernel = true;
/*
* Both cpus and threads are now owned by evlist
* and will be freed by following perf_evlist__set_maps
* call. Getting refference to keep them alive.
*/
cpu_map__get(cpus);
thread_map__get(threads);
perf_evlist__set_maps(evlist, NULL, NULL);
perf_evlist__delete(evlist);
evlist = NULL;
continue;
}
if (verbose) {
char errbuf[512];
perf_evlist__strerror_open(evlist, errno, errbuf, sizeof(errbuf));
pr_debug("perf_evlist__open() failed!\n%s\n", errbuf);
}
goto out_put;
}
break;
}
ret = perf_evlist__mmap(evlist, UINT_MAX, false);
if (ret < 0) {
pr_debug("perf_evlist__mmap failed\n");
goto out_put;
}
perf_evlist__enable(evlist);
do_something();
perf_evlist__disable(evlist);
ret = process_events(machine, evlist, &state);
if (ret < 0)
goto out_put;
if (!have_vmlinux && !have_kcore && !try_kcore)
err = TEST_CODE_READING_NO_KERNEL_OBJ;
else if (!have_vmlinux && !try_kcore)
err = TEST_CODE_READING_NO_VMLINUX;
else if (excl_kernel)
err = TEST_CODE_READING_NO_ACCESS;
else
err = TEST_CODE_READING_OK;
out_put:
thread__put(thread);
out_err:
if (evlist) {
perf_evlist__delete(evlist);
} else {
cpu_map__put(cpus);
thread_map__put(threads);
}
machine__delete_threads(machine);
machine__delete(machine);
return err;
}
int test__code_reading(int subtest __maybe_unused)
{
int ret;
ret = do_test_code_reading(false);
if (!ret)
ret = do_test_code_reading(true);
switch (ret) {
case TEST_CODE_READING_OK:
return 0;
case TEST_CODE_READING_NO_VMLINUX:
pr_debug("no vmlinux\n");
return 0;
case TEST_CODE_READING_NO_KCORE:
pr_debug("no kcore\n");
return 0;
case TEST_CODE_READING_NO_ACCESS:
pr_debug("no access\n");
return 0;
case TEST_CODE_READING_NO_KERNEL_OBJ:
pr_debug("no kernel obj\n");
return 0;
default:
return -1;
};
}