[v3,3/5] selftests/resctrl: Flush stdout file buffer before executing fork()
Commit Message
When a process has buffered output, a child process created by fork()
will also copy buffered output. When using kselftest framework,
the output (resctrl test result message) will be printed multiple times.
Add fflush() to flush out the buffered output before executing fork().
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
---
tools/testing/selftests/resctrl/cat_test.c | 1 +
tools/testing/selftests/resctrl/resctrl_val.c | 1 +
tools/testing/selftests/resctrl/resctrlfs.c | 1 +
3 files changed, 3 insertions(+)
Comments
On 11/1/22 03:43, Shaopeng Tan wrote:
> When a process has buffered output, a child process created by fork()
> will also copy buffered output. When using kselftest framework,
> the output (resctrl test result message) will be printed multiple times.
>
> Add fflush() to flush out the buffered output before executing fork().
>
> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
> Signed-off-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
> ---
> tools/testing/selftests/resctrl/cat_test.c | 1 +
> tools/testing/selftests/resctrl/resctrl_val.c | 1 +
> tools/testing/selftests/resctrl/resctrlfs.c | 1 +
> 3 files changed, 3 insertions(+)
>
> diff --git a/tools/testing/selftests/resctrl/cat_test.c b/tools/testing/selftests/resctrl/cat_test.c
> index 1c5e90c63254..6a8306b0a109 100644
> --- a/tools/testing/selftests/resctrl/cat_test.c
> +++ b/tools/testing/selftests/resctrl/cat_test.c
> @@ -167,6 +167,7 @@ int cat_perf_miss_val(int cpu_no, int n, char *cache_type)
> return errno;
> }
>
> + fflush(stdout);
> bm_pid = fork();
>
> /* Set param values for child thread which will be allocated bitmask
> diff --git a/tools/testing/selftests/resctrl/resctrl_val.c b/tools/testing/selftests/resctrl/resctrl_val.c
> index b32b96356ec7..6948843bf995 100644
> --- a/tools/testing/selftests/resctrl/resctrl_val.c
> +++ b/tools/testing/selftests/resctrl/resctrl_val.c
> @@ -629,6 +629,7 @@ int resctrl_val(char **benchmark_cmd, struct resctrl_val_param *param)
> * Fork to start benchmark, save child's pid so that it can be killed
> * when needed
> */
> + fflush(stdout);
> bm_pid = fork();
> if (bm_pid == -1) {
> perror("# Unable to fork");
> diff --git a/tools/testing/selftests/resctrl/resctrlfs.c b/tools/testing/selftests/resctrl/resctrlfs.c
> index 8546bc9f1786..d95688298469 100644
> --- a/tools/testing/selftests/resctrl/resctrlfs.c
> +++ b/tools/testing/selftests/resctrl/resctrlfs.c
> @@ -678,6 +678,7 @@ int filter_dmesg(void)
> perror("pipe");
> return ret;
> }
> + fflush(stdout);
> pid = fork();
> if (pid == 0) {
> close(pipefds[0]);
Good find. Looks good to me.
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
thanks,
-- Shuah
@@ -167,6 +167,7 @@ int cat_perf_miss_val(int cpu_no, int n, char *cache_type)
return errno;
}
+ fflush(stdout);
bm_pid = fork();
/* Set param values for child thread which will be allocated bitmask
@@ -629,6 +629,7 @@ int resctrl_val(char **benchmark_cmd, struct resctrl_val_param *param)
* Fork to start benchmark, save child's pid so that it can be killed
* when needed
*/
+ fflush(stdout);
bm_pid = fork();
if (bm_pid == -1) {
perror("# Unable to fork");
@@ -678,6 +678,7 @@ int filter_dmesg(void)
perror("pipe");
return ret;
}
+ fflush(stdout);
pid = fork();
if (pid == 0) {
close(pipefds[0]);