4 files changed, 120 insertions, 68 deletions

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index c3ac5415c097..4799195ed246 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 eb6a13881887..32ee6ca8eabd 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 b774341e797f..a472247af191 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 231c06f8286b..07d56b3e6d61 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);