[PATCH v10 3/4] tests/intel/xe_sysfs_timeslice_duration: Restore preempt timeout

[Upadhyay, Tejas]

> -----Original Message-----
> From: Cavitt, Jonathan <jonathan.cavitt at intel.com>
> Sent: Thursday, December 5, 2024 3:54 AM
> To: igt-dev at lists.freedesktop.org
> Cc: Cavitt, Jonathan <jonathan.cavitt at intel.com>; Gupta, saurabhg
> <saurabhg.gupta at intel.com>; Zuo, Alex <alex.zuo at intel.com>;
> kamil.konieczny at linux.intel.com; Belgaumkar, Vinay
> <vinay.belgaumkar at intel.com>; Upadhyay, Tejas
> <tejas.upadhyay at intel.com>
> Subject: [PATCH v10 3/4] tests/intel/xe_sysfs_timeslice_duration: Restore
> preempt timeout
> 
> The subtests of sysfs_timeslice_duration modify the preempt_timeout_us and
> timeslice_duration_us values.  However, while the test does restore the
> timeslice_duration_us value at the end of execution, it does not do the same
> for preempt_timeout_us.  Because the value is not properly restored, future
> tests can end up using the unexpected preempt timeout value and thus have
> unexpected behavior.
> 
> Save and restore the preempt_timeout_us value during the test.
> 
> This fix does not apply to xe_sysfs_preempt_timeout because only the
> preempt_timeout_us is modified during those tests, and the value is correcty
> restored before the tests end.
> 
> v2: Also restore preempt_timeout_us on test failure (Kamil)

Restoring timeouts after test looks ok here, you can add my r-o-b for that. But if there is value already set via sysfs manually which is not default values then we still have chance to hit the issues we are fixing here. I have tested this manually what I am talking here.

I think restoring or setting up these timeout values to default before other igt tests like igt at xe_vm@bind-execqueues-independent is very important or else low values of these timeout set manually via sysfs (echo value > timeout) might fail the test.

Although I am not very sure storing restoring timeout values should be based on default values or not. @Brost, Matthew any input here?

Tejas
> 
> v3: Abort on restore failure (Kamil)
> 
> Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/2976
> Signed-off-by: Jonathan Cavitt <jonathan.cavitt at intel.com>
> CC: Vinay Belgaumkar <vinay.belgaumkar at intel.com>
> CC: Kamil Konieczny <kamil.konieczny at linux.intel.com>
> Reviewed-by: Kamil Konieczny <kamil.konieczny at linux.intel.com>
> ---
>  tests/intel/xe_sysfs_timeslice_duration.c | 19 +++++++++++++++++--
>  1 file changed, 17 insertions(+), 2 deletions(-)
> 
> diff --git a/tests/intel/xe_sysfs_timeslice_duration.c
> b/tests/intel/xe_sysfs_timeslice_duration.c
> index 899093a9df..752672691f 100644
> --- a/tests/intel/xe_sysfs_timeslice_duration.c
> +++ b/tests/intel/xe_sysfs_timeslice_duration.c
> @@ -115,10 +115,11 @@ static uint64_t __test_timeout(int fd, int engine,
> unsigned int timeout, uint16_  static void test_timeout(int fd, int engine, const
> char **property, uint16_t class, int gt)  {
>  	uint64_t delays[] = { 1000, 50000, 100000, 500000 };
> -	unsigned int saved;
> +	unsigned int saved, old_pt;
>  	uint64_t elapsed;
>  	uint64_t epsilon;
> 
> +	igt_assert(igt_sysfs_scanf(engine, "preempt_timeout_us", "%u",
> +&old_pt) == 1);
>  	igt_require(igt_sysfs_printf(engine, "preempt_timeout_us", "%u", 1)
> == 1);
>  	igt_assert(igt_sysfs_scanf(engine, property[0], "%u", &saved) == 1);
>  	igt_debug("Initial %s:%u\n", property[0], saved); @@ -140,6 +141,9
> @@ static void test_timeout(int fd, int engine, const char **property, uint16_t
> cla
>  	}
> 
>  	set_timeslice_duration(engine, saved);
> +	igt_assert_lte(0, igt_sysfs_printf(engine, "preempt_timeout_us",
> "%u", old_pt));
> +	igt_sysfs_scanf(engine, "preempt_timeout_us", "%u", &saved);
> +	igt_assert_eq(saved, old_pt);
>  }
> 
>  #define	MAX_GTS	8
> @@ -159,6 +163,7 @@ igt_main
>  	int gt_count = 0;
>  	int fd = -1, sys_fd, gt;
>  	int engines_fd[MAX_GTS], gt_fd[MAX_GTS];
> +	unsigned int pts[MAX_GTS][XE_MAX_ENGINE_INSTANCE];
>  	unsigned int tds[MAX_GTS][XE_MAX_ENGINE_INSTANCE];
>  	int *engine_list[MAX_GTS];
> 
> @@ -184,6 +189,8 @@ igt_main
>  			while (list[i] != -1) {
>  				igt_require(igt_sysfs_scanf(list[i],
> "timeslice_duration_us", "%u",
>  							    &tds[gt_count][i])
> == 1);
> +				igt_require(igt_sysfs_scanf(list[i],
> "preempt_timeout_us", "%u",
> +							    &pts[gt_count][i])
> == 1);
>  				i++;
>  			}
> 
> @@ -215,8 +222,16 @@ igt_main
>  			while (list[j] != -1) {
>  				unsigned int store = UINT_MAX;
> 
> +				igt_sysfs_printf(list[j], "preempt_timeout_us",
> +						 "%u", pts[i][j]);
> +				igt_sysfs_scanf(list[j], "preempt_timeout_us",
> +						"%u", &store);
> +				igt_abort_on_f(store != pts[i][j],
> +					       "preempt_timeout_us not
> restored!\n");
> +
> +				store = UINT_MAX;
>  				igt_sysfs_printf(list[j],
> "timeslice_duration_us",
> -						"%u", tds[i][j]);
> +						 "%u", tds[i][j]);
>  				igt_sysfs_scanf(list[j],
> "timeslice_duration_us",
>  						"%u", &store);
>  				igt_abort_on_f(store != tds[i][j],
> --
> 2.43.0