Re: [v2,3/4] lib/xe: use debugfs info to implement xe_engine_class_supports_multi_queue()

Daniel Charles
2026-04-06T22:34:26Z

On 4/3/2026 12:13 AM, Xin Wang wrote:
> Update xe_engine_class_supports_multi_queue() to take a device fd and
> use the kernel-reported multi_queue_engine_classes bitmask from debugfs
> when available, with a fallback to the hardcoded default for older KMD.
>
> Propagate the new fd argument through the xe_for_each_multi_queue_engine
> and xe_for_each_multi_queue_engine_class macros and all their call sites.
>
> Signed-off-by: Xin Wang <x.wang@intel.com>
> ---
> lib/xe/xe_query.c | 52 ++++++++++++++++++-------------
> lib/xe/xe_query.h | 8 ++---
> tests/intel/xe_exec_multi_queue.c | 4 +--
> tests/intel/xe_exec_threads.c | 4 +--
> 4 files changed, 38 insertions(+), 30 deletions(-)
>
> diff --git a/lib/xe/xe_query.c b/lib/xe/xe_query.c
> index e13d5e143..3286a3b37 100644
> --- a/lib/xe/xe_query.c
> +++ b/lib/xe/xe_query.c
> @@ -215,28 +215,6 @@ static uint16_t xe_device_query_engine_class_mask(int fd, const char *key)
> return mask;
> }
>
> -/**
> - * xe_engine_class_supports_multi_queue:
> - * @engine_class: engine class
> - *
> - * Returns true if multi queue supported by engine class or false.
> - */
> -bool xe_engine_class_supports_multi_queue(uint32_t engine_class)
> -{
> - switch (engine_class) {
> - case DRM_XE_ENGINE_CLASS_COPY:
> - case DRM_XE_ENGINE_CLASS_COMPUTE:
> - return true;
> - case DRM_XE_ENGINE_CLASS_RENDER:
> - case DRM_XE_ENGINE_CLASS_VIDEO_DECODE:
> - case DRM_XE_ENGINE_CLASS_VIDEO_ENHANCE:
> - return false;
> - default:
> - igt_warn("Engine class 0x%x unknown\n", engine_class);
> - return false;
> - }
> -}
> -
> /**
> * xe_engine_class_string:
> * @engine_class: engine class
> @@ -338,6 +316,36 @@ bool xe_engine_class_supports_multi_lrc(int fd, uint32_t engine_class)
> }
> }
>
> +/**
> + * xe_engine_class_supports_multi_queue:
> + * @fd: xe device fd
> + * @engine_class: engine class
> + *
> + * Returns true if multi queue supported by engine class or false.
> + * Uses the kernel-reported bitmask from debugfs when available, otherwise
> + * falls back to the hardcoded per-class default.
> + */
> +bool xe_engine_class_supports_multi_queue(int fd, uint32_t engine_class)
> +{
> + struct xe_device *xe_dev = find_in_cache(fd);
> +
> + if (xe_dev && xe_dev->multi_queue_engine_class_mask != UINT16_MAX)
> + return !!(xe_dev->multi_queue_engine_class_mask & BIT(engine_class));
> +
> + switch (engine_class) {
> + case DRM_XE_ENGINE_CLASS_COPY:
> + case DRM_XE_ENGINE_CLASS_COMPUTE:
> + return true;
> + case DRM_XE_ENGINE_CLASS_RENDER:
> + case DRM_XE_ENGINE_CLASS_VIDEO_DECODE:
> + case DRM_XE_ENGINE_CLASS_VIDEO_ENHANCE:
> + return false;
> + default:
> + igt_warn("Engine class 0x%x unknown\n", engine_class);
> + return false;
> + }
> +}
> +
> static void xe_device_free(struct xe_device *xe_dev)
> {
> free(xe_dev->config);
> diff --git a/lib/xe/xe_query.h b/lib/xe/xe_query.h
> index 5c26a3e88..8815c6c66 100644
> --- a/lib/xe/xe_query.h
> +++ b/lib/xe/xe_query.h
> @@ -113,10 +113,10 @@ struct xe_device {
>
> #define xe_for_each_multi_queue_engine(__fd, __hwe) \
> xe_for_each_engine(__fd, __hwe) \
> - for_if(xe_engine_class_supports_multi_queue((__hwe)->engine_class))
> -#define xe_for_each_multi_queue_engine_class(__class) \
> + for_if(xe_engine_class_supports_multi_queue(__fd, (__hwe)->engine_class))
> +#define xe_for_each_multi_queue_engine_class(__fd, __class) \
> xe_for_each_engine_class(__class) \
> - for_if(xe_engine_class_supports_multi_queue(__class))
> + for_if(xe_engine_class_supports_multi_queue(__fd, __class))
>
> #define XE_IS_CLASS_SYSMEM(__region) ((__region)->mem_class == DRM_XE_MEM_REGION_CLASS_SYSMEM)
> #define XE_IS_CLASS_VRAM(__region) ((__region)->mem_class == DRM_XE_MEM_REGION_CLASS_VRAM)
> @@ -161,7 +161,7 @@ uint32_t xe_get_default_alignment(int fd);
> uint32_t xe_va_bits(int fd);
> uint16_t xe_dev_id(int fd);
> int xe_supports_faults(int fd);
> -bool xe_engine_class_supports_multi_queue(uint32_t engine_class);
> +bool xe_engine_class_supports_multi_queue(int fd, uint32_t engine_class);
> bool xe_engine_class_supports_multi_lrc(int fd, uint32_t engine_class);
> const char *xe_engine_class_string(uint32_t engine_class);
> const char *xe_engine_class_short_string(uint32_t engine_class);
> diff --git a/tests/intel/xe_exec_multi_queue.c b/tests/intel/xe_exec_multi_queue.c
> index f987f8d6a..b5ded0633 100644
> --- a/tests/intel/xe_exec_multi_queue.c
> +++ b/tests/intel/xe_exec_multi_queue.c
> @@ -1052,7 +1052,7 @@ int igt_main()
>
> igt_subtest_f("sanity")
> xe_for_each_gt(fd, gt)
> - xe_for_each_multi_queue_engine_class(class)
> + xe_for_each_multi_queue_engine_class(fd, class)
> test_sanity(fd, gt, class);
>
> igt_subtest_f("exec-sanity")
> @@ -1061,7 +1061,7 @@ int igt_main()
>
> igt_subtest_f("virtual")
> xe_for_each_gt(fd, gt)
> - xe_for_each_multi_queue_engine_class(class)
> + xe_for_each_multi_queue_engine_class(fd, class)
> test_exec_virtual(fd, gt, class);
>
> igt_subtest_f("priority")
> diff --git a/tests/intel/xe_exec_threads.c b/tests/intel/xe_exec_threads.c
> index f082a0eda..ab9565beb 100644
> --- a/tests/intel/xe_exec_threads.c
> +++ b/tests/intel/xe_exec_threads.c
> @@ -1141,7 +1141,7 @@ static void threads(int fd, int flags)
> int gt;
>
> xe_for_each_engine(fd, hwe) {
> - if ((flags & MULTI_QUEUE) && !xe_engine_class_supports_multi_queue(hwe->engine_class))
> + if ((flags & MULTI_QUEUE) && !xe_engine_class_supports_multi_queue(fd, hwe->engine_class))
> continue;
> ++n_engines;
> }
> @@ -1170,7 +1170,7 @@ static void threads(int fd, int flags)
> }
>
> xe_for_each_engine(fd, hwe) {
> - if ((flags & MULTI_QUEUE) && !xe_engine_class_supports_multi_queue(hwe->engine_class))
> + if ((flags & MULTI_QUEUE) && !xe_engine_class_supports_multi_queue(fd, hwe->engine_class))
> continue;
> threads_data[i].mutex = &mutex;
> threads_data[i].cond = &cond;
Reviewed-by:Daniel Charles <daniel.charles@intel.com>