Re: [LTP] [PATCH 2/2] getitimer01: add checking for nonzero timer

[Richard Palethorpe <rpalethorpe@suse.de>]

Hello,

Li Wang <liwang@redhat.com> writes:

> By default a new process disabled the timer and getitimer()
> returned zero value. But we also need to check if the timer
> is correct when reset to nonzero.
>
> Signed-off-by: Li Wang <liwang@redhat.com>
> ---
>
> Notes:
>       The reason for using jiffy instead of time_step is that it only
>       checks the timer is set expectedly but not really expired. So we
>       use a rough value in the macro definition is enough.
>
>  .../kernel/syscalls/getitimer/getitimer01.c   | 84 ++++++++++++++++---
>  1 file changed, 71 insertions(+), 13 deletions(-)
>
> diff --git a/testcases/kernel/syscalls/getitimer/getitimer01.c b/testcases/kernel/syscalls/getitimer/getitimer01.c
> index 5ecfac55c..a49f63a85 100644
> --- a/testcases/kernel/syscalls/getitimer/getitimer01.c
> +++ b/testcases/kernel/syscalls/getitimer/getitimer01.c
> @@ -12,25 +12,83 @@
>   */
>  
>  #include "tst_test.h"
> +#include "tst_safe_clocks.h"
>  
> -static int itimer_name[] = {
> -	ITIMER_REAL,
> -	ITIMER_VIRTUAL,
> -	ITIMER_PROF,
> +#define SEC  100
> +#define USEC 10000
> +
> +static struct itimerval *value;
> +static long jiffy;
> +
> +static struct tcase {
> +	int which;
> +	char *des;
> +} tcases[] = {
> +	{ITIMER_REAL,    "ITIMER_REAL"},
> +	{ITIMER_VIRTUAL, "ITIMER_VIRTUAL"},
> +	{ITIMER_PROF,    "ITIMER_PROF"},
>  };
>  
> -static void run(void)
> +static void set_setitimer_value(int sec, int usec)
>  {
> -	long unsigned int i;
> -	struct itimerval value;
> +	value->it_value.tv_sec = sec;
> +	value->it_value.tv_usec = usec;
> +	value->it_interval.tv_sec = sec;
> +	value->it_interval.tv_usec = usec;
> +}
>  
> -	for (i = 0; i < ARRAY_SIZE(itimer_name); i++) {
> -		TST_EXP_PASS(getitimer(itimer_name[i], &value));
> -		TST_EXP_EQ_LI(value.it_value.tv_sec, 0);
> -		TST_EXP_EQ_LI(value.it_value.tv_usec, 0);
> -	}
> +static void verify_getitimer(unsigned int i)
> +{
> +	struct tcase *tc = &tcases[i];
> +
> +	tst_res(TINFO, "tc->which = %s", tc->des);
> +
> +	TST_EXP_PASS(getitimer(tc->which, value));
> +	TST_EXP_EQ_LI(value->it_value.tv_sec, 0);
> +	TST_EXP_EQ_LI(value->it_value.tv_usec, 0);
> +	TST_EXP_EQ_LI(value->it_interval.tv_sec, 0);
> +	TST_EXP_EQ_LI(value->it_interval.tv_usec, 0);
> +
> +	set_setitimer_value(SEC, USEC);
> +	TST_EXP_PASS(setitimer(tc->which, value, NULL));
> +
> +	set_setitimer_value(0, 0);
> +	TST_EXP_PASS(getitimer(tc->which, value));
> +
> +	TST_EXP_EQ_LI(value->it_interval.tv_sec, SEC);
> +	TST_EXP_EQ_LI(value->it_interval.tv_usec, USEC);
> +
> +	tst_res(TINFO, "value->it_value.tv_sec=%ld, value->it_value.tv_usec=%ld",
> +			value->it_value.tv_sec, value->it_value.tv_usec);
> +
> +	/*
> +	 * ITIMER_VIRTUAL and ITIMER_PROF timers always expire a
> +	 * TICK_NSEC (jiffy) afterward the elapsed time to make
> +	 * sure that at least time counters take effect.
> +	 */
> +	long margin = (tc->which == ITIMER_REAL) ? 0 : jiffy;
> +
> +	if (value->it_value.tv_sec > SEC ||
> +			value->it_value.tv_usec > USEC + margin)

If a second is able to elapse then it_value.tv_usec can be greater than
USEC + margin. Or is there something I am missing?

I guess again there is the issue with wall clock time jumping around.

> +		tst_res(TFAIL, "timer value is not within the expected range");
> +	else
> +		tst_res(TPASS, "timer value is within the expected
> range");

Also we want to print all the relevant values in case of failure.

> +}
> +
> +static void setup(void)
> +{
> +	struct timespec time_res;
> +
> +	SAFE_CLOCK_GETRES(CLOCK_MONOTONIC_COARSE, &time_res);
> +	jiffy = (time_res.tv_nsec + 999) / 1000;
>  }
>  
>  static struct tst_test test = {
> -	.test_all = run
> +	.tcnt = ARRAY_SIZE(tcases),
> +	.setup = setup,
> +	.test = verify_getitimer,
> +	.bufs = (struct tst_buffers[]) {
> +		{&value,  .size = sizeof(struct itimerval)},
> +		{}
> +	}
>  };
> -- 
> 2.35.3


-- 
Thank you,
Richard.

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