[igt-dev] [PATCH v3 01/24] drm-uapi/xe_drm: Align with new PMU interface

[Tvrtko Ursulin]

On 26/09/2023 14:00, Francois Dugast wrote:
> From: Rodrigo Vivi <rodrigo.vivi at intel.com>
> 
> Align with commit ("drm/xe/pmu: Enable PMU interface")
> 
> Cc: Francois Dugast <francois.dugast at intel.com>
> Cc: Aravind Iddamsetty <aravind.iddamsetty at linux.intel.com>
> Signed-off-by: Francois Dugast <francois.dugast at intel.com>
> Signed-off-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
> ---
>   include/drm-uapi/xe_drm.h | 38 ++++++++++++++++++++++++++++++++++++++
>   1 file changed, 38 insertions(+)
> 
> diff --git a/include/drm-uapi/xe_drm.h b/include/drm-uapi/xe_drm.h
> index 804c02270..643eb6e82 100644
> --- a/include/drm-uapi/xe_drm.h
> +++ b/include/drm-uapi/xe_drm.h
> @@ -1053,6 +1053,44 @@ struct drm_xe_vm_madvise {
>   	__u64 reserved[2];
>   };
>   
> +/**
> + * DOC: XE PMU event config IDs
> + *
> + * Check 'man perf_event_open' to use these ID's in 'struct perf_event_attr'
> + * as part of perf_event_open syscall to read a particular event.
> + *
> + * For example to open the XE_PMU_INTERRUPTS(0):
> + *
> + * .. code-block:: C
> + *	struct perf_event_attr attr;
> + *	long long count;
> + *	int cpu = 0;
> + *	int fd;
> + *
> + *	memset(&attr, 0, sizeof(struct perf_event_attr));
> + *	attr.type = type; // eg: /sys/bus/event_source/devices/xe_0000_56_00.0/type
> + *	attr.read_format = PERF_FORMAT_TOTAL_TIME_ENABLED;
> + *	attr.use_clockid = 1;
> + *	attr.clockid = CLOCK_MONOTONIC;
> + *	attr.config = XE_PMU_INTERRUPTS(0);
> + *
> + *	fd = syscall(__NR_perf_event_open, &attr, -1, cpu, -1, 0);
> + */
> +
> +/*
> + * Top bits of every counter are GT id.
> + */
> +#define __XE_PMU_GT_SHIFT (56)
> +
> +#define ___XE_PMU_OTHER(gt, x) \
> +	(((__u64)(x)) | ((__u64)(gt) << __XE_PMU_GT_SHIFT))
> +
> +#define XE_PMU_INTERRUPTS(gt)			___XE_PMU_OTHER(gt, 0)

AFAIR interrupts is probably the least useful counter and I don't 
remember that anyone asked much about it. Therefore I'd say it could be 
worth seeing if you could just drop it. Changes to intel_gpu_top to work 
with the below set (no per engine, no frequencies) will have to be 
extensive already anyway.

Regards,

Tvrtko

> +#define XE_PMU_RENDER_GROUP_BUSY(gt)		___XE_PMU_OTHER(gt, 1)
> +#define XE_PMU_COPY_GROUP_BUSY(gt)		___XE_PMU_OTHER(gt, 2)
> +#define XE_PMU_MEDIA_GROUP_BUSY(gt)		___XE_PMU_OTHER(gt, 3)
> +#define XE_PMU_ANY_ENGINE_GROUP_BUSY(gt)	___XE_PMU_OTHER(gt, 4)
> +
>   #if defined(__cplusplus)
>   }
>   #endif