[ROCm][Kernel] Using the correct warp_size value

[gshtras]

The code assumes WARP_SIZE to be equal to 32, based on the hard-coded values of shared int32_t shared_counts[32][8];
This is not the case on ROCm, which leads to half the array not being initialized

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[mgoin]

cc @chenyang78 @LucasWilkinson

[chenyang78]

Hmm, seems WARP_SIZE is defined to be 32 for ROCM?

vllm/csrc/cuda_compat.h

Lines 7 to 11 in bc1bdec

	#ifndef USE_ROCM
	#define WARP_SIZE 32
	#else
	#define WARP_SIZE warpSize
	#endif

Caveat: I am new to vllm so I could be wrong :)

@LucasWilkinson may take a look, too. Thanks!

[gshtras]

#define WARP_SIZE warpSize

builtin warpSize is 64
Note that hard-coded 32 is in the ifndef USE_ROCM

[chenyang78]

#define WARP_SIZE warpSize

builtin warpSize is 64 Note that hard-coded 32 is in the ifndef USE_ROCM

Ah, it's ifndef :) My mistake. Sorry for the noise.

[LucasWilkinson]

LGTM, although im not a ROCm expert

[houseroad]

Wondering it's warp size affecting the accuracy or perf or both?