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Subject[PATCH 06/25] perf evlist: Introduce {prepare,start}_workload refactored from 'perf record'
Date
From: Arnaldo Carvalho de Melo <acme@redhat.com>

So that we can easily start a workload in other tools.

Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-zdsksd4aphu0nltg2lpwsw3x@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/builtin-record.c | 81 ++++++------------------------------
tools/perf/perf.h | 1 +
tools/perf/util/evlist.c | 96 +++++++++++++++++++++++++++++++++++++++++++
tools/perf/util/evlist.h | 10 ++++
4 files changed, 120 insertions(+), 68 deletions(-)
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index c3ac541..4799195 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -47,11 +47,9 @@ static struct perf_record_opts record_opts = {
static unsigned int page_size;
static unsigned int mmap_pages = UINT_MAX;
static int output;
-static int pipe_output = 0;
static const char *output_name = NULL;
static bool group = false;
static int realtime_prio = 0;
-static pid_t child_pid = -1;
static enum write_mode_t write_mode = WRITE_FORCE;
static bool no_buildid = false;
static bool no_buildid_cache = false;
@@ -144,9 +142,9 @@ static void sig_atexit(void)
{
int status;

- if (child_pid > 0) {
+ if (evsel_list->workload.pid > 0) {
if (!child_finished)
- kill(child_pid, SIGTERM);
+ kill(evsel_list->workload.pid, SIGTERM);

wait(&status);
if (WIFSIGNALED(status))
@@ -304,7 +302,7 @@ static int process_buildids(void)

static void atexit_header(void)
{
- if (!pipe_output) {
+ if (!record_opts.pipe_output) {
session->header.data_size += bytes_written;

if (!no_buildid)
@@ -377,9 +375,7 @@ static int __cmd_record(int argc, const char **argv)
int flags;
int err;
unsigned long waking = 0;
- int child_ready_pipe[2], go_pipe[2];
const bool forks = argc > 0;
- char buf;
struct machine *machine;

progname = argv[0];
@@ -391,20 +387,15 @@ static int __cmd_record(int argc, const char **argv)
signal(SIGINT, sig_handler);
signal(SIGUSR1, sig_handler);

- if (forks && (pipe(child_ready_pipe) < 0 || pipe(go_pipe) < 0)) {
- perror("failed to create pipes");
- exit(-1);
- }
-
if (!output_name) {
if (!fstat(STDOUT_FILENO, &st) && S_ISFIFO(st.st_mode))
- pipe_output = true;
+ record_opts.pipe_output = true;
else
output_name = "perf.data";
}
if (output_name) {
if (!strcmp(output_name, "-"))
- pipe_output = true;
+ record_opts.pipe_output = true;
else if (!stat(output_name, &st) && st.st_size) {
if (write_mode == WRITE_FORCE) {
char oldname[PATH_MAX];
@@ -424,7 +415,7 @@ static int __cmd_record(int argc, const char **argv)
else
flags |= O_TRUNC;

- if (pipe_output)
+ if (record_opts.pipe_output)
output = STDOUT_FILENO;
else
output = open(output_name, flags, S_IRUSR | S_IWUSR);
@@ -470,57 +461,11 @@ static int __cmd_record(int argc, const char **argv)
mmap_pages = (512 * 1024) / page_size;

if (forks) {
- child_pid = fork();
- if (child_pid < 0) {
- perror("failed to fork");
- exit(-1);
- }
-
- if (!child_pid) {
- if (pipe_output)
- dup2(2, 1);
- close(child_ready_pipe[0]);
- close(go_pipe[1]);
- fcntl(go_pipe[0], F_SETFD, FD_CLOEXEC);
-
- /*
- * Do a dummy execvp to get the PLT entry resolved,
- * so we avoid the resolver overhead on the real
- * execvp call.
- */
- execvp("", (char **)argv);
-
- /*
- * Tell the parent we're ready to go
- */
- close(child_ready_pipe[1]);
-
- /*
- * Wait until the parent tells us to go.
- */
- if (read(go_pipe[0], &buf, 1) == -1)
- perror("unable to read pipe");
-
- execvp(argv[0], (char **)argv);
-
- perror(argv[0]);
- kill(getppid(), SIGUSR1);
- exit(-1);
- }
-
- if (!record_opts.system_wide && record_opts.target_tid == -1 && record_opts.target_pid == -1)
- evsel_list->threads->map[0] = child_pid;
-
- close(child_ready_pipe[1]);
- close(go_pipe[0]);
- /*
- * wait for child to settle
- */
- if (read(child_ready_pipe[0], &buf, 1) == -1) {
- perror("unable to read pipe");
- exit(-1);
+ err = perf_evlist__prepare_workload(evsel_list, &record_opts, argv);
+ if (err < 0) {
+ pr_err("Couldn't run the workload!\n");
+ goto out_delete_session;
}
- close(child_ready_pipe[0]);
}

open_counters(evsel_list);
@@ -530,7 +475,7 @@ static int __cmd_record(int argc, const char **argv)
*/
atexit(atexit_header);

- if (pipe_output) {
+ if (record_opts.pipe_output) {
err = perf_header__write_pipe(output);
if (err < 0)
return err;
@@ -543,7 +488,7 @@ static int __cmd_record(int argc, const char **argv)

post_processing_offset = lseek(output, 0, SEEK_CUR);

- if (pipe_output) {
+ if (record_opts.pipe_output) {
err = perf_session__synthesize_attrs(session,
process_synthesized_event);
if (err < 0) {
@@ -629,7 +574,7 @@ static int __cmd_record(int argc, const char **argv)
* Let the child rip
*/
if (forks)
- close(go_pipe[1]);
+ perf_evlist__start_workload(evsel_list);

for (;;) {
int hits = samples;
diff --git a/tools/perf/perf.h b/tools/perf/perf.h
index eb6a138..32ee6ca 100644
--- a/tools/perf/perf.h
+++ b/tools/perf/perf.h
@@ -193,6 +193,7 @@ struct perf_record_opts {
bool no_delay;
bool no_inherit;
bool no_samples;
+ bool pipe_output;
bool raw_samples;
bool sample_address;
bool sample_time;
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index b774341..a472247 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -13,6 +13,7 @@
#include "thread_map.h"
#include "evlist.h"
#include "evsel.h"
+#include <unistd.h>

#include "parse-events.h"

@@ -33,6 +34,7 @@ void perf_evlist__init(struct perf_evlist *evlist, struct cpu_map *cpus,
INIT_HLIST_HEAD(&evlist->heads[i]);
INIT_LIST_HEAD(&evlist->entries);
perf_evlist__set_maps(evlist, cpus, threads);
+ evlist->workload.pid = -1;
}

struct perf_evlist *perf_evlist__new(struct cpu_map *cpus,
@@ -674,3 +676,97 @@ out_err:

return err;
}
+
+int perf_evlist__prepare_workload(struct perf_evlist *evlist,
+ struct perf_record_opts *opts,
+ const char *argv[])
+{
+ int child_ready_pipe[2], go_pipe[2];
+ char bf;
+
+ if (pipe(child_ready_pipe) < 0) {
+ perror("failed to create 'ready' pipe");
+ return -1;
+ }
+
+ if (pipe(go_pipe) < 0) {
+ perror("failed to create 'go' pipe");
+ goto out_close_ready_pipe;
+ }
+
+ evlist->workload.pid = fork();
+ if (evlist->workload.pid < 0) {
+ perror("failed to fork");
+ goto out_close_pipes;
+ }
+
+ if (!evlist->workload.pid) {
+ if (opts->pipe_output)
+ dup2(2, 1);
+
+ close(child_ready_pipe[0]);
+ close(go_pipe[1]);
+ fcntl(go_pipe[0], F_SETFD, FD_CLOEXEC);
+
+ /*
+ * Do a dummy execvp to get the PLT entry resolved,
+ * so we avoid the resolver overhead on the real
+ * execvp call.
+ */
+ execvp("", (char **)argv);
+
+ /*
+ * Tell the parent we're ready to go
+ */
+ close(child_ready_pipe[1]);
+
+ /*
+ * Wait until the parent tells us to go.
+ */
+ if (read(go_pipe[0], &bf, 1) == -1)
+ perror("unable to read pipe");
+
+ execvp(argv[0], (char **)argv);
+
+ perror(argv[0]);
+ kill(getppid(), SIGUSR1);
+ exit(-1);
+ }
+
+ if (!opts->system_wide && opts->target_tid == -1 && opts->target_pid == -1)
+ evlist->threads->map[0] = evlist->workload.pid;
+
+ close(child_ready_pipe[1]);
+ close(go_pipe[0]);
+ /*
+ * wait for child to settle
+ */
+ if (read(child_ready_pipe[0], &bf, 1) == -1) {
+ perror("unable to read pipe");
+ goto out_close_pipes;
+ }
+
+ evlist->workload.cork_fd = go_pipe[1];
+ close(child_ready_pipe[0]);
+ return 0;
+
+out_close_pipes:
+ close(go_pipe[0]);
+ close(go_pipe[1]);
+out_close_ready_pipe:
+ close(child_ready_pipe[0]);
+ close(child_ready_pipe[1]);
+ return -1;
+}
+
+int perf_evlist__start_workload(struct perf_evlist *evlist)
+{
+ if (evlist->workload.cork_fd > 0) {
+ /*
+ * Remove the cork, let it rip!
+ */
+ return close(evlist->workload.cork_fd);
+ }
+
+ return 0;
+}
diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
index 231c06f..07d56b3 100644
--- a/tools/perf/util/evlist.h
+++ b/tools/perf/util/evlist.h
@@ -6,6 +6,7 @@
#include "../perf.h"
#include "event.h"
#include "util.h"
+#include <unistd.h>

struct pollfd;
struct thread_map;
@@ -22,6 +23,10 @@ struct perf_evlist {
int nr_fds;
int nr_mmaps;
int mmap_len;
+ struct {
+ int cork_fd;
+ pid_t pid;
+ } workload;
bool overwrite;
union perf_event event_copy;
struct perf_mmap *mmap;
@@ -68,6 +73,11 @@ int perf_evlist__open(struct perf_evlist *evlist, bool group);
void perf_evlist__config_attrs(struct perf_evlist *evlist,
struct perf_record_opts *opts);

+int perf_evlist__prepare_workload(struct perf_evlist *evlist,
+ struct perf_record_opts *opts,
+ const char *argv[]);
+int perf_evlist__start_workload(struct perf_evlist *evlist);
+
int perf_evlist__alloc_mmap(struct perf_evlist *evlist);
int perf_evlist__mmap(struct perf_evlist *evlist, int pages, bool overwrite);
void perf_evlist__munmap(struct perf_evlist *evlist);
--
1.7.8.rc0.35.gee6df


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