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authorArnaldo Carvalho de Melo <acme@redhat.com>2011-11-09 08:47:15 -0200
committerArnaldo Carvalho de Melo <acme@redhat.com>2011-11-28 10:26:14 -0200
commit35b9d88ecd8c5fb720ba0dd325262f356d0b03e7 (patch)
tree536902f734862d5b04a6122c81386fddb19f4bcd /tools/perf/util/evlist.c
parent0f82ebc452f921590e216b28eee0b41f5e434a48 (diff)
perf evlist: Introduce {prepare,start}_workload refactored from 'perf record'
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>
Diffstat (limited to 'tools/perf/util/evlist.c')
-rw-r--r--tools/perf/util/evlist.c96
1 files changed, 96 insertions, 0 deletions
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;
+}