Re: [PATCH v2] tests/intel/xe_vm: Always have at least 2 pages bound in hammer sections

[Matthew Auld <matthew.auld@intel.com>]

On 10/04/2024 02:21, Matthew Brost wrote:
> If the prefetch buffer is 2k or larger the hammer sections will prefetch
> the next page, if the page is unbound a fault will occur. Account for
> larger prefetchs by always having at least 2 pages bound for the hammer
> thread.

Is this referring to bb_start pre-fetch? It should be + 4K at most for 
xe2. Is it possible to make the test consider xe_cs_prefetch_size() 
somehow instead of hardcoding? Or perhaps that is tricky here? Otherwise 
maybe we can add an assert that xe_cs_prefetch_size() remains <= 4K for 
this test, with comment explaining what needs to change if we start 
triggering the assert? Thinking is that would be easier to debug and fix 
than seeing CAT errors, faults etc. if the pre-fetch changes again.

> 
> v2:
>   - Missed table entry
> 
> Signed-off-by: Matthew Brost <matthew.brost@intel.com>
> ---
>   tests/intel/xe_vm.c | 16 ++++++++--------
>   1 file changed, 8 insertions(+), 8 deletions(-)
> 
> diff --git a/tests/intel/xe_vm.c b/tests/intel/xe_vm.c
> index bd4973cc38..9f9f61b7ef 100644
> --- a/tests/intel/xe_vm.c
> +++ b/tests/intel/xe_vm.c
> @@ -1843,12 +1843,12 @@ igt_main
>   		{ "all", 4, 2, 0, 4, 0 },
>   		{ "one-partial", 4, 1, 1, 2, 0 },
>   		{ "either-side-partial", 4, 2, 1, 2, 0 },
> -		{ "either-side-partial-hammer", 4, 2, 1, 2,
> +		{ "either-side-partial-hammer", 6, 2, 2, 2,
>   			MAP_FLAG_HAMMER_FIRST_PAGE },
> -		{ "either-side-partial-split-page-hammer", 4, 2, 1, 2,
> +		{ "either-side-partial-split-page-hammer", 6, 2, 2, 2,
>   			MAP_FLAG_HAMMER_FIRST_PAGE |
>   			MAP_FLAG_LARGE_PAGE },
> -		{ "either-side-partial-large-page-hammer", 4, 2, 1, 2,
> +		{ "either-side-partial-large-page-hammer", 6, 2, 2, 2,
>   			MAP_FLAG_HAMMER_FIRST_PAGE |
>   			MAP_FLAG_LARGE_PAGE |
>   			MAP_FLAG_LARGE_PAGE_NO_SPLIT },
> @@ -1857,7 +1857,7 @@ igt_main
>   		{ "front", 4, 2, 1, 3, 0 },
>   		{ "many-all", 4 * 8, 2 * 8, 0 * 8, 4 * 8, 0 },
>   		{ "many-either-side-partial", 4 * 8, 2 * 8, 1, 4 * 8 - 2, 0 },
> -		{ "many-either-side-partial-hammer", 4 * 8, 2 * 8, 1, 4 * 8 - 2,
> +		{ "many-either-side-partial-hammer", 4 * 8, 2 * 8, 2, 4 * 8 - 4,
>   			MAP_FLAG_HAMMER_FIRST_PAGE },
>   		{ "many-either-side-full", 4 * 8, 4 * 8, 1 * 8, 2 * 8, 0 },
>   		{ "many-end", 4 * 8, 4, 0 * 8, 3 * 8 + 2, 0 },
> @@ -1902,12 +1902,12 @@ igt_main
>   		{ "one-partial", 4, 1, 1, 2, 0 },
>   		{ "either-side-partial", 4, 2, 1, 2, 0 },
>   		{ "either-side-full", 4, 4, 1, 2, 0 },
> -		{ "either-side-partial-hammer", 4, 2, 1, 2,
> +		{ "either-side-partial-hammer", 6, 2, 2, 2,
>   			MAP_FLAG_HAMMER_FIRST_PAGE },
> -		{ "either-side-partial-split-page-hammer", 4, 2, 1, 2,
> +		{ "either-side-partial-split-page-hammer", 6, 2, 2, 2,
>   			MAP_FLAG_HAMMER_FIRST_PAGE |
>   			MAP_FLAG_LARGE_PAGE },
> -		{ "either-side-partial-large-page-hammer", 4, 2, 1, 2,
> +		{ "either-side-partial-large-page-hammer", 6, 2, 2, 2,
>   			MAP_FLAG_HAMMER_FIRST_PAGE |
>   			MAP_FLAG_LARGE_PAGE |
>   			MAP_FLAG_LARGE_PAGE_NO_SPLIT },
> @@ -1915,7 +1915,7 @@ igt_main
>   		{ "front", 4, 2, 1, 3, 0 },
>   		{ "many-all", 4 * 8, 2 * 8, 0 * 8, 4 * 8, 0 },
>   		{ "many-either-side-partial", 4 * 8, 2 * 8, 1, 4 * 8 - 2, 0 },
> -		{ "many-either-side-partial-hammer", 4 * 8, 2 * 8, 1, 4 * 8 - 2,
> +		{ "many-either-side-partial-hammer", 4 * 8, 2 * 8, 2, 4 * 8 - 4,
>   			MAP_FLAG_HAMMER_FIRST_PAGE },
>   		{ "userptr-all", 4, 2, 0, 4, MAP_FLAG_USERPTR },
>   		{ "userptr-one-partial", 4, 1, 1, 2, MAP_FLAG_USERPTR },