From: "Steven Rostedt (Google)" <rostedt@xxxxxxxxxxx>
Have trace-cmd stream periodically signal the recorder tasks to flush some
output, otherwise it will look empty for a long time (especially with the
default setting of a 50 percent buffering, where the ring buffers will not
return read until they are half full).
Add a "finish" flag to tracecmd_flush_recording() that will keep the old
behavior when set, but when not set, it will only do a single
tracefs_cpu_flush() that will output some data, but not all of it.
Use the SIGUSR2 to signal the recorder tasks to do the flush.
Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
---
.../include/private/trace-cmd-private.h | 2 +-
lib/trace-cmd/trace-recorder.c | 10 ++++-
tracecmd/trace-record.c | 41 +++++++++++++++----
3 files changed, 43 insertions(+), 10 deletions(-)
diff --git a/lib/trace-cmd/include/private/trace-cmd-private.h b/lib/trace-cmd/include/private/trace-cmd-private.h
index 2cb6f35cb250..e8b0989ac67e 100644
--- a/lib/trace-cmd/include/private/trace-cmd-private.h
+++ b/lib/trace-cmd/include/private/trace-cmd-private.h
@@ -378,7 +378,7 @@ struct tracecmd_recorder *tracecmd_create_buffer_recorder_maxkb(const char *file
int tracecmd_start_recording(struct tracecmd_recorder *recorder, unsigned long sleep);
void tracecmd_stop_recording(struct tracecmd_recorder *recorder);
-long tracecmd_flush_recording(struct tracecmd_recorder *recorder);
+long tracecmd_flush_recording(struct tracecmd_recorder *recorder, bool finish);
enum tracecmd_msg_flags {
TRACECMD_MSG_FL_USE_TCP = 1 << 0,
diff --git a/lib/trace-cmd/trace-recorder.c b/lib/trace-cmd/trace-recorder.c
index bb02f7b8ee11..79b95ce1193d 100644
--- a/lib/trace-cmd/trace-recorder.c
+++ b/lib/trace-cmd/trace-recorder.c
@@ -366,13 +366,19 @@ static long move_data(struct tracecmd_recorder *recorder)
return ret;
}
-long tracecmd_flush_recording(struct tracecmd_recorder *recorder)
+long tracecmd_flush_recording(struct tracecmd_recorder *recorder, bool finish)
{
char buf[recorder->subbuf_size];
long total = 0;
long wrote = 0;
long ret;
+ if (!recorder)
+ return 0;
+
+ if (!finish)
+ return tracefs_cpu_flush_write(recorder->tcpu, recorder->fd);
+
set_nonblock(recorder);
do {
@@ -421,7 +427,7 @@ int tracecmd_start_recording(struct tracecmd_recorder *recorder, unsigned long s
} while (!recorder->stop);
/* Flush out the rest */
- ret = tracecmd_flush_recording(recorder);
+ ret = tracecmd_flush_recording(recorder, true);
if (ret < 0)
return ret;
diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
index cc6f27bf22e8..a03d334a65d5 100644
--- a/tracecmd/trace-record.c
+++ b/tracecmd/trace-record.c
@@ -1641,12 +1641,21 @@ static inline void ptrace_attach(struct buffer_instance *instance, int pid) { }
static void trace_or_sleep(enum trace_type type, bool pwait)
{
struct timeval tv = { 1 , 0 };
+ int i;
if (pwait)
ptrace_wait(type);
- else if (type & TRACE_TYPE_STREAM)
- trace_stream_read(pids, recorder_threads, &tv);
- else
+ else if (type & TRACE_TYPE_STREAM) {
+ /* Returns zero if it did not read anything (and did a sleep) */
+ if (trace_stream_read(pids, recorder_threads, &tv) > 0)
+ return;
+ /* Force a flush if nothing was read (including on errors) */
+ for (i = 0; i < recorder_threads; i++) {
+ if (pids[i].pid > 0) {
+ kill(pids[i].pid, SIGUSR2);
+ }
+ }
+ } else
sleep(10);
}
@@ -3156,7 +3165,7 @@ static void expand_event_list(void)
expand_event_instance(instance);
}
-static void finish(int sig)
+static void finish(void)
{
/* all done */
if (recorder)
@@ -3164,6 +3173,23 @@ static void finish(int sig)
finished = 1;
}
+static void flush(void)
+{
+ if (recorder)
+ tracecmd_flush_recording(recorder, false);
+}
+
+static void do_sig(int sig)
+{
+ switch (sig) {
+ case SIGUSR1:
+ case SIGINT:
+ return finish();
+ case SIGUSR2:
+ return flush();
+ }
+}
+
static struct addrinfo *do_getaddrinfo(const char *host, unsigned int port,
enum port_type type)
{
@@ -3405,7 +3431,8 @@ static int create_recorder(struct buffer_instance *instance, int cpu,
return pid;
signal(SIGINT, SIG_IGN);
- signal(SIGUSR1, finish);
+ signal(SIGUSR1, do_sig);
+ signal(SIGUSR2, do_sig);
if (rt_prio)
set_prio(rt_prio);
@@ -3451,7 +3478,7 @@ static int create_recorder(struct buffer_instance *instance, int cpu,
die ("can't create recorder");
if (type == TRACE_TYPE_EXTRACT) {
- ret = tracecmd_flush_recording(recorder);
+ ret = tracecmd_flush_recording(recorder, true);
tracecmd_free_recorder(recorder);
recorder = NULL;
return ret;
@@ -6945,7 +6972,7 @@ static void record_trace(int argc, char **argv,
allocate_seq();
if (type & (TRACE_TYPE_RECORD | TRACE_TYPE_STREAM)) {
- signal(SIGINT, finish);
+ signal(SIGINT, do_sig);
if (!latency)
start_threads(type, ctx);
}
--
2.35.1
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