trace_waitpid() loop hogs one CPU during trace-cmd record. Add a delay there to
slow down the loop, to reduce the CPU load.
Signed-off-by: Vincent Stehlé <vincent.stehle@xxxxxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
---
Changes since v1:
- Use nanosleep and sleep_time from command line.
trace-record.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/trace-record.c b/trace-record.c
index 18e2e2d..a230fde 100644
--- a/trace-record.c
+++ b/trace-record.c
@@ -837,6 +837,7 @@ static pid_t trace_waitpid(enum trace_type type, pid_t pid, int *status, int opt
struct timeval tv = { 1, 0 };
int ret;
int profile = (type & TRACE_TYPE_PROFILE) == TRACE_TYPE_PROFILE;
+ struct timespec req;
options |= WNOHANG;
@@ -847,6 +848,11 @@ static pid_t trace_waitpid(enum trace_type type, pid_t pid, int *status, int opt
if (type & TRACE_TYPE_STREAM)
trace_stream_read(pids, recorder_threads, &tv, profile);
+
+ req.tv_sec = sleep_time / 1000000;
+ req.tv_nsec = (sleep_time % 1000000) * 1000;
+ nanosleep(&req, NULL);
+
} while (1);
}
#ifndef NO_PTRACE
--
2.1.4
--
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