Re: [PATCH] tests/intel/xe_pmu: Tie preempt timeout to exec quantum

[Michal Wajdeczko <michal.wajdeczko@intel.com>]

On 11/6/2025 11:12 PM, Jonathan Cavitt wrote:
> When updating the exec quantum in enable_and_provision_vfs, update the
> preempt timeout value to be double the exec quantum value.  Also, reset
> the preempt timeout value on test end in unprovision_and_disable_vfs.
> The value for the preempt timeout here was chosen because it's what
> we've used historically for cases like this.

while PT = 2x EQ was a common setting for VFs expected to run regular WLs,
I'm not sure that this would be a correct value for this particular test,
which verifies reporting of the engine activity - maybe PT shall be very
small or equal PT (depending on actual WL's type submitted by the test)

> 
> Suggested-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
> Signed-off-by: Jonathan Cavitt <jonathan.cavitt@intel.com>
> ---
>  tests/intel/xe_pmu.c | 14 +++++++++++---
>  1 file changed, 11 insertions(+), 3 deletions(-)
> 
> diff --git a/tests/intel/xe_pmu.c b/tests/intel/xe_pmu.c
> index 9525655ba2..e7c2d82da4 100644
> --- a/tests/intel/xe_pmu.c
> +++ b/tests/intel/xe_pmu.c
> @@ -987,12 +987,18 @@ static unsigned int enable_and_provision_vfs(int fd)
>  	num_vfs = igt_sriov_get_enabled_vfs(fd);
>  	igt_require(num_vfs == 2);
>  
> -	/* Set 32ms for VF execution quantum and 64ms for PF execution quantum */
> +	/*
> +	 * Set 32ms for VF execution quantum and 64ms for PF execution quantum.
> +	 * Set the preempt timeout for the VF and PF to be double their execution quantum.
> +	 */
>  	xe_for_each_gt(fd, gt) {
>  		xe_sriov_set_sched_if_idle(fd, gt, 0);
> -		for (int fn = 0; fn <= num_vfs; fn++)
> +		for (int fn = 0; fn <= num_vfs; fn++) {
>  			xe_sriov_set_exec_quantum_ms(fd, fn, gt, fn ? vf_exec_quantum :
>  						     pf_exec_quantum);
> +			xe_sriov_set_preempt_timeout_us(fd, fn, gt, 2000 *
> +							(fn ? vf_exec_quantum : pf_exec_quantum));

maybe better to have some temp vars/const with these pf/vf preempt_timeout values
like it is done for vf/pf exec_quantum
so we will have them defined together

> +		}
>  	}
>  
>  	/* probe VFs */
> @@ -1011,8 +1017,10 @@ static void unprovision_and_disable_vfs(int fd)
>  
>  	xe_for_each_gt(fd, gt) {
>  		xe_sriov_set_sched_if_idle(fd, gt, 0);
> -		for (int fn = 0; fn <= num_vfs; fn++)
> +		for (int fn = 0; fn <= num_vfs; fn++) {
>  			xe_sriov_set_exec_quantum_ms(fd, fn, gt, 0);
> +			xe_sriov_set_preempt_timeout_us(fd, fn, gt, 0);
> +		}
>  	}
>  
>  	xe_sriov_disable_vfs_restore_auto_provisioning(fd);