Bug 93469

Summary:	get_sub_group_id and get_sub_group_size do not return the correct values
Product:	Beignet	Reporter:	Georg Kolling <georg.kolling>
Component:	Beignet	Assignee:	Zhigang Gong <zhigang.gong>
Status:	RESOLVED FIXED	QA Contact:
Severity:	minor
Priority:	medium	CC:	rong.r.yang, yejun.guo, zhigang.gong
Version:	unspecified
Hardware:	All
OS:	Linux (All)
Whiteboard:
i915 platform:		i915 features:

Description Georg Kolling 2015-12-21 17:06:59 UTC

On branch master and Release_v1.1, Beignet implements a subset of the cl_intel_subgroups extension (https://www.khronos.org/registry/cl/extensions/intel/cl_intel_subgroups.txt). However, some functions do not behave according to the spec:

get_sub_group_size() is mapped to OP_SIMD_SIZE which returns the constant SIMD width. This is what get_max_sub_group_size() should return. get_sub_group_size() may be smaller than that for the last subgroup in a work group.

get_sub_group_id() is mapped to OP_SIMD_ID which returns the SIMD lane ID. However, the SIMD lane ID is the equivalent of get_sub_group_local_id().

Comment 1 Zhigang Gong 2015-12-22 01:48:01 UTC

Thanks for pointing the issue out. You are right, the current implementation doesn't fully comply with the spec.

Yejun, could you take a look at this bug and make our implementation comply?

Thanks,
Zhigang Gong.

Comment 2 Zhigang Gong 2015-12-22 01:55:28 UTC

Thanks for pointing the issue out. You are right, the current implementation doesn't fully comply with the spec.

Yejun, could you take a look at this bug and make our implementation comply?

Thanks,
Zhigang Gong.

Comment 3 Guo Yejun 2015-12-22 02:01:36 UTC

thanks, yes, the real function should be get_max_sub_group_size and get_sub_group_local_id, i'll fix it accordingly.

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