[Intel-gfx] [PATCH 02/19] drm/i915/perf: Add OA formats for DG2

Lionel Landwerlin lionel.g.landwerlin at intel.com
Tue Sep 6 19:35:16 UTC 2022


On 23/08/2022 23:41, Umesh Nerlige Ramappa wrote:
> Add new OA formats for DG2. Some of the newer OA formats are not
> multples of 64 bytes and are not powers of 2. For those formats, adjust
> hw_tail accordingly when checking for new reports.
>
> Signed-off-by: Umesh Nerlige Ramappa <umesh.nerlige.ramampa at intel.com>

Apart from the coding style issue :


Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin at intel.com>


> ---
>   drivers/gpu/drm/i915/i915_perf.c | 63 ++++++++++++++++++++------------
>   include/uapi/drm/i915_drm.h      |  6 +++
>   2 files changed, 46 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c
> index 735244a3aedd..c8331b549d31 100644
> --- a/drivers/gpu/drm/i915/i915_perf.c
> +++ b/drivers/gpu/drm/i915/i915_perf.c
> @@ -306,7 +306,8 @@ static u32 i915_oa_max_sample_rate = 100000;
>   
>   /* XXX: beware if future OA HW adds new report formats that the current
>    * code assumes all reports have a power-of-two size and ~(size - 1) can
> - * be used as a mask to align the OA tail pointer.
> + * be used as a mask to align the OA tail pointer. In some of the
> + * formats, R is used to denote reserved field.
>    */
>   static const struct i915_oa_format oa_formats[I915_OA_FORMAT_MAX] = {
>   	[I915_OA_FORMAT_A13]	    = { 0, 64 },
> @@ -320,6 +321,10 @@ static const struct i915_oa_format oa_formats[I915_OA_FORMAT_MAX] = {
>   	[I915_OA_FORMAT_A12]		    = { 0, 64 },
>   	[I915_OA_FORMAT_A12_B8_C8]	    = { 2, 128 },
>   	[I915_OA_FORMAT_A32u40_A4u32_B8_C8] = { 5, 256 },
> +	[I915_OAR_FORMAT_A32u40_A4u32_B8_C8]    = { 5, 256 },
> +	[I915_OA_FORMAT_A24u40_A14u32_B8_C8]    = { 5, 256 },
> +	[I915_OAR_FORMAT_A36u64_B8_C8]		= { 1, 384 },
> +	[I915_OA_FORMAT_A38u64_R2u64_B8_C8]	= { 1, 448 },
>   };
>   
>   #define SAMPLE_OA_REPORT      (1<<0)
> @@ -467,6 +472,7 @@ static bool oa_buffer_check_unlocked(struct i915_perf_stream *stream)
>   	bool pollin;
>   	u32 hw_tail;
>   	u64 now;
> +	u32 partial_report_size;
>   
>   	/* We have to consider the (unlikely) possibility that read() errors
>   	 * could result in an OA buffer reset which might reset the head and
> @@ -476,10 +482,16 @@ static bool oa_buffer_check_unlocked(struct i915_perf_stream *stream)
>   
>   	hw_tail = stream->perf->ops.oa_hw_tail_read(stream);
>   
> -	/* The tail pointer increases in 64 byte increments,
> -	 * not in report_size steps...
> +	/* The tail pointer increases in 64 byte increments, whereas report
> +	 * sizes need not be integral multiples or 64 or powers of 2.
> +	 * Compute potentially partially landed report in the OA buffer
>   	 */
> -	hw_tail &= ~(report_size - 1);
> +	partial_report_size = OA_TAKEN(hw_tail, stream->oa_buffer.tail);
> +	partial_report_size %= report_size;
> +
> +	/* Subtract partial amount off the tail */
> +	hw_tail = gtt_offset + ((hw_tail - partial_report_size) &
> +				(stream->oa_buffer.vma->size - 1));
>   
>   	now = ktime_get_mono_fast_ns();
>   
> @@ -601,6 +613,8 @@ static int append_oa_sample(struct i915_perf_stream *stream,
>   {
>   	int report_size = stream->oa_buffer.format_size;
>   	struct drm_i915_perf_record_header header;
> +	int report_size_partial;
> +	u8 *oa_buf_end;
>   
>   	header.type = DRM_I915_PERF_RECORD_SAMPLE;
>   	header.pad = 0;
> @@ -614,7 +628,19 @@ static int append_oa_sample(struct i915_perf_stream *stream,
>   		return -EFAULT;
>   	buf += sizeof(header);
>   
> -	if (copy_to_user(buf, report, report_size))
> +	oa_buf_end = stream->oa_buffer.vaddr +
> +		     stream->oa_buffer.vma->size;
> +	report_size_partial = oa_buf_end - report;
> +
> +	if (report_size_partial < report_size) {
> +		if(copy_to_user(buf, report, report_size_partial))
> +			return -EFAULT;
> +		buf += report_size_partial;
> +
> +		if(copy_to_user(buf, stream->oa_buffer.vaddr,
> +				report_size - report_size_partial))
> +			return -EFAULT;

I think the coding style requires you to use if () not if()


Just a suggestion : you could make this code deal with the partial bit 
as the main bit of the function :


oa_buf_end = stream->oa_buffer.vaddr +
	     stream->oa_buffer.vma->size;

report_size_partial = oa_buf_end - report;

if (copy_to_user(buf, report, report_size_partial))
	return -EFAULT;
buf += report_size_partial;

if (report_size_partial < report_size &&
     copy_to_user(buf, stream->oa_buffer.vaddr,
		report_size - report_size_partial))
	return -EFAULT;
buf += report_size - report_size_partial;


> +	} else if (copy_to_user(buf, report, report_size))
>   		return -EFAULT;
>   
>   	(*offset) += header.size;
> @@ -684,8 +710,8 @@ static int gen8_append_oa_reports(struct i915_perf_stream *stream,
>   	 * all a power of two).
>   	 */
>   	if (drm_WARN_ONCE(&uncore->i915->drm,
> -			  head > OA_BUFFER_SIZE || head % report_size ||
> -			  tail > OA_BUFFER_SIZE || tail % report_size,
> +			  head > stream->oa_buffer.vma->size ||
> +			  tail > stream->oa_buffer.vma->size,
>   			  "Inconsistent OA buffer pointers: head = %u, tail = %u\n",
>   			  head, tail))
>   		return -EIO;
> @@ -699,22 +725,6 @@ static int gen8_append_oa_reports(struct i915_perf_stream *stream,
>   		u32 ctx_id;
>   		u32 reason;
>   
> -		/*
> -		 * All the report sizes factor neatly into the buffer
> -		 * size so we never expect to see a report split
> -		 * between the beginning and end of the buffer.
> -		 *
> -		 * Given the initial alignment check a misalignment
> -		 * here would imply a driver bug that would result
> -		 * in an overrun.
> -		 */
> -		if (drm_WARN_ON(&uncore->i915->drm,
> -				(OA_BUFFER_SIZE - head) < report_size)) {
> -			drm_err(&uncore->i915->drm,
> -				"Spurious OA head ptr: non-integral report offset\n");
> -			break;
> -		}
> -
>   		/*
>   		 * The reason field includes flags identifying what
>   		 * triggered this specific report (mostly timer
> @@ -4513,6 +4523,13 @@ static void oa_init_supported_formats(struct i915_perf *perf)
>   		oa_format_add(perf, I915_OA_FORMAT_C4_B8);
>   		break;
>   
> +	case INTEL_DG2:
> +		oa_format_add(perf, I915_OAR_FORMAT_A32u40_A4u32_B8_C8);
> +		oa_format_add(perf, I915_OA_FORMAT_A24u40_A14u32_B8_C8);
> +		oa_format_add(perf, I915_OAR_FORMAT_A36u64_B8_C8);
> +		oa_format_add(perf, I915_OA_FORMAT_A38u64_R2u64_B8_C8);
> +		break;
> +
>   	default:
>   		MISSING_CASE(platform);
>   	}
> diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
> index 520ad2691a99..d20d723925b5 100644
> --- a/include/uapi/drm/i915_drm.h
> +++ b/include/uapi/drm/i915_drm.h
> @@ -2650,6 +2650,12 @@ enum drm_i915_oa_format {
>   	I915_OA_FORMAT_A12_B8_C8,
>   	I915_OA_FORMAT_A32u40_A4u32_B8_C8,
>   
> +	/* DG2 */
> +	I915_OAR_FORMAT_A32u40_A4u32_B8_C8,
> +	I915_OA_FORMAT_A24u40_A14u32_B8_C8,
> +	I915_OAR_FORMAT_A36u64_B8_C8,
> +	I915_OA_FORMAT_A38u64_R2u64_B8_C8,
> +
>   	I915_OA_FORMAT_MAX	    /* non-ABI */
>   };
>   




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