trace_waitpid() loop hogs one CPU during trace-cmd record. Slow it down by
making waitpid() hang for all non-stream cases (as per Steven's solution).
Signed-off-by: Vincent Stehlé <vincent.stehle@xxxxxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
---
On 02/04/2015 08:07 PM, Steven Rostedt wrote:
> As you pointed it out, please send a new patch.
Hi Steven,
Thank you! Here is a v3 patch, which works for me on ARM and x86.
Best regards,
V.
Changes since v2:
- Make waitpid() hang instead of using nanosleep, as per Steven's solution.
Changes since v1:
- Use nanosleep and sleep_time from command line.
trace-record.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/trace-record.c b/trace-record.c
index 18e2e2d..3cb943d 100644
--- a/trace-record.c
+++ b/trace-record.c
@@ -838,7 +838,8 @@ static pid_t trace_waitpid(enum trace_type type, pid_t pid, int *status, int opt
int ret;
int profile = (type & TRACE_TYPE_PROFILE) == TRACE_TYPE_PROFILE;
- options |= WNOHANG;
+ if (type & TRACE_TYPE_STREAM)
+ options |= WNOHANG;
do {
ret = waitpid(pid, status, options);
--
2.1.4
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