[LTP] [PATCH v4 1/2] lib: introduce tst_timeout_remaining()

[Cyril Hrubis <chrubis@suse.cz>]

On Thu, Aug 30, 2018 at 10:55:18AM +0200, Jan Stancek wrote:
> Which returns number of seconds remaining until timeout.
> Along with tst_start_time it is only valid for test pid.
> 
> Its value has to be (re)initialized when:
> - test starts
> - test calls tst_set_timeout()
> - test runs multiple iterations or uses .all_filesystems
> 
> Signed-off-by: Jan Stancek <jstancek@redhat.com>
> ---
> Changes in v4:
> - drop tst_timer_find_clock(), use CLOCK_MONOTONIC
> - reinitialize in heartbeat(), so we cover -i parameter and tst_set_timeout()
> - modify test18 so it sleeps
> - add test18 .gitignore
> - add note to docs
> 
>  doc/test-writing-guidelines.txt |  3 +++
>  include/tst_test.h              |  1 +
>  lib/newlib_tests/.gitignore     |  1 +
>  lib/newlib_tests/test18.c       | 34 ++++++++++++++++++++++++++++++++++
>  lib/tst_test.c                  | 22 ++++++++++++++++++++++
>  5 files changed, 61 insertions(+)
>  create mode 100644 lib/newlib_tests/test18.c
> 
> diff --git a/doc/test-writing-guidelines.txt b/doc/test-writing-guidelines.txt
> index a16972430b14..0194f2098d26 100644
> --- a/doc/test-writing-guidelines.txt
> +++ b/doc/test-writing-guidelines.txt
> @@ -324,6 +324,9 @@ overriden by setting '.timeout' in the test structure or by calling
>  time may vary arbitrarily, for these timeout can be disabled by setting it to
>  -1.
>  
> +Test can find out how much time (in seconds) is remaining to timeout,
> +by calling 'tst_timeout_remaining()'.
> +
>  A word about the cleanup() callback
>  +++++++++++++++++++++++++++++++++++
>  
> 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/.gitignore b/lib/newlib_tests/.gitignore
> index 99edc640438e..76e89e438f55 100644
> --- a/lib/newlib_tests/.gitignore
> +++ b/lib/newlib_tests/.gitignore
> @@ -19,6 +19,7 @@ tst_safe_fileops
>  tst_res_hexd
>  tst_strstatus
>  test17
> +test18
>  tst_expiration_timer
>  test_exec
>  test_exec_child
> diff --git a/lib/newlib_tests/test18.c b/lib/newlib_tests/test18.c
> new file mode 100644
> index 000000000000..6615471a5708
> --- /dev/null
> +++ b/lib/newlib_tests/test18.c
> @@ -0,0 +1,34 @@
> +/*
> + * 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 <unistd.h>
> +#include "tst_test.h"
> +
> +static void run(void)
> +{
> +	do {
> +		sleep(1);
> +	} while (tst_timeout_remaining() >= 4);
> +
> +	tst_res(TPASS, "Timeout remaining: %d", tst_timeout_remaining());
> +}
> +
> +static struct tst_test test = {
> +	.test_all = run,
> +	.timeout = 5
> +};
> diff --git a/lib/tst_test.c b/lib/tst_test.c
> index 2f3d357d2fcc..ae3ca6182581 100644
> --- a/lib/tst_test.c
> +++ b/lib/tst_test.c
> @@ -47,6 +47,7 @@ static int iterations = 1;
>  static float duration = -1;
>  static pid_t main_pid, lib_pid;
>  static int mntpoint_mounted;
> +static struct timespec tst_start_time; /* valid only for test pid */
>  
>  struct results {
>  	int passed;
> @@ -916,6 +917,9 @@ static void add_paths(void)
>  
>  static void heartbeat(void)
>  {
> +	if (tst_clock_gettime(CLOCK_MONOTONIC, &tst_start_time))
> +		tst_res(TWARN | TERRNO, "tst_clock_gettime() failed");
> +
>  	kill(getppid(), SIGUSR1);
>  }
>  
> @@ -925,6 +929,9 @@ static void testrun(void)
>  	unsigned long long stop_time = 0;
>  	int cont = 1;
>  
> +	if (tst_clock_gettime(CLOCK_MONOTONIC, &tst_start_time))
> +		tst_res(TWARN | TERRNO, "tst_clock_gettime() failed");
>  	add_paths();
>  	do_test_setup();
>  
> @@ -992,6 +999,21 @@ static void sigint_handler(int sig LTP_ATTRIBUTE_UNUSED)
>  	}
>  }

Looks correct to me.

I do wonder if it shouldn't suffice to add clock_gettime at the start of
the run_test() function. That would mean that we would be taking the
timestamps slightly out-of-sync with the code that sets the alarm, but I
doubt that it will matter for a result with resolution in seconds.

> +unsigned int tst_timeout_remaining(void)
> +{
> +	static struct timespec now;
> +	unsigned int elapsed;
> +
> +	if (tst_clock_gettime(CLOCK_MONOTONIC, &now))
> +		tst_res(TWARN | TERRNO, "tst_clock_gettime() failed");
> +
> +	elapsed = tst_timespec_diff_ms(now, tst_start_time) / 1000;

Maybe we should round this correctly to be more conservative:

elapsed = (tst_timespec_diff_ms(now, tst_start_time) + 500) / 1000;

> +	if (results->timeout > elapsed)
> +		return results->timeout - elapsed;
> +
> +	return 0;
> +}
> +
>  void tst_set_timeout(int timeout)
>  {
>  	char *mul = getenv("LTP_TIMEOUT_MUL");



-- 
Cyril Hrubis
chrubis@suse.cz