[LTP] [PATCH RFC v3 2/3] lib: introduce tst_timeout_remaining()

[Cyril Hrubis <chrubis@suse.cz>]

Hi!
> Which returns number of seconds remaining till timeout.
> 
> Signed-off-by: Jan Stancek <jstancek@redhat.com>
> ---
>  include/tst_test.h        |   1 +
>  lib/newlib_tests/test18   | Bin 0 -> 384032 bytes
>  lib/newlib_tests/test18.c |  32 ++++++++++++++++++++++++++++++++
>  lib/tst_test.c            |  21 +++++++++++++++++++++
>  4 files changed, 54 insertions(+)
>  create mode 100755 lib/newlib_tests/test18
>  create mode 100644 lib/newlib_tests/test18.c
> 
> diff --git a/include/tst_test.h b/include/tst_test.h
> index 98dacf3873ab..c0c9a7c7b995 100644
> --- a/include/tst_test.h
> +++ b/include/tst_test.h
> @@ -217,6 +217,7 @@ const char *tst_strsig(int sig);
>   */
>  const char *tst_strstatus(int status);
>  
> +unsigned int tst_timeout_remaining(void);
>  void tst_set_timeout(int timeout);
>  
>  #ifndef TST_NO_DEFAULT_MAIN
> diff --git a/lib/newlib_tests/test18 b/lib/newlib_tests/test18
> new file mode 100755
> index 000000000000..01dc1d7976fe
> Binary files /dev/null and b/lib/newlib_tests/test18 differ
> diff --git a/lib/newlib_tests/test18.c b/lib/newlib_tests/test18.c
> new file mode 100644
> index 000000000000..aba007d3689c
> --- /dev/null
> +++ b/lib/newlib_tests/test18.c
> @@ -0,0 +1,32 @@
> +/*
> + * Copyright (c) 2018, Linux Test Project
> + *
> + * This program is free software: you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation, either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program. If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include <stdlib.h>
> +#include "tst_test.h"
> +
> +static void run(void)
> +{
> +	unsigned int remaining = tst_timeout_remaining();

Maybe we should do something as:

	while (tst_timeout_remaining() > 2)
		sleep(1);

	tst_res(TPASS, ...);

And set timeout in tst_test to something as 10s, to really test the API.

> +	if (remaining >= 200)
> +		tst_res(TPASS, "Timeout remaining: %d", remaining);
> +	else
> +		tst_res(TFAIL, "Timeout remaining: %d", remaining);
> +}
> +
> +static struct tst_test test = {
> +	.test_all = run,
> +};
> diff --git a/lib/tst_test.c b/lib/tst_test.c
> index 2f3d357d2fcc..75619fabffa4 100644
> --- a/lib/tst_test.c
> +++ b/lib/tst_test.c
> @@ -47,6 +47,8 @@ static int iterations = 1;
>  static float duration = -1;
>  static pid_t main_pid, lib_pid;
>  static int mntpoint_mounted;
> +static clockid_t tst_clock;
> +static struct timespec tst_start_time;
>  
>  struct results {
>  	int passed;
> @@ -758,6 +760,7 @@ static void do_setup(int argc, char *argv[])
>  
>  	if (tst_test->sample)
>  		tst_test = tst_timer_test_setup(tst_test);
> +	tst_clock = tst_timer_find_clock();

I wonder if we really need this, we were running with CLOCK_MONOTONIC
timer in the testrun() for quite some time now and nobody complained so
far.

Well I guess that it would be nice to use CLOCK_MONOTONIC_COARSE for the
tst_timeout_remaining if available, which should save us some CPU since
it's supposed to be called in a loop.

>  	parse_opts(argc, argv);
>  
> @@ -992,6 +995,21 @@ static void sigint_handler(int sig LTP_ATTRIBUTE_UNUSED)
>  	}
>  }
>  
> +unsigned int tst_timeout_remaining(void)
> +{
> +	static struct timespec now;
> +	unsigned int elapsed;
> +
> +	if (tst_clock_gettime(tst_clock, &now))
> +		tst_res(TWARN | TERRNO, "tst_clock_gettime() failed");
> +
> +	elapsed = tst_timespec_diff_ms(now, tst_start_time) / 1000;
> +	if (results->timeout > elapsed)
> +		return results->timeout - elapsed;
> +
> +	return 0;
> +}

This is obviously correct.

>  void tst_set_timeout(int timeout)
>  {
>  	char *mul = getenv("LTP_TIMEOUT_MUL");
> @@ -1012,6 +1030,9 @@ void tst_set_timeout(int timeout)
>  		results->timeout = results->timeout * m + 0.5;
>  	}
>  
> +	if (tst_clock_gettime(tst_clock, &tst_start_time))
> +		tst_res(TWARN | TERRNO, "tst_clock_gettime() failed");

Looking into this, this will not work with the -i option, since the
timeout is restarted after each iteration in heartbeat_handler().
However clock_gettime() is supposedly signal-safe. So as far as I can
tell we have to take the timestamp in the heartbeat_handler() instead
and that should be it.

-- 
Cyril Hrubis
chrubis@suse.cz