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"""Utility methods for generic GPU.""" |
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from typing import List, Optional |
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from tvm import tir |
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from tvm.target import Target |
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def max_threads_per_block(target: Target) -> int: |
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"""Get the maximum number of threads per block for a given target. |
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Parameters |
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---------- |
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target : Target |
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The target to get the maximum number of threads per block for. |
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Returns |
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------- |
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max_threads_per_block : int |
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The maximum number of threads per block for the given target. |
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""" |
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for name in ["max_threads_per_block", "max_num_threads"]: |
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result = target.attrs.get(name, None) |
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if result is not None: |
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return result |
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if target.kind.name == "cuda": |
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return 1024 |
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return 256 |
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def suggest_threads_per_block( |
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target: Target, |
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loops: List[tir.For], |
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max_threads_for_dynamic_loop: int = 32, |
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) -> List[int]: |
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if target.kind.name == "cuda": |
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threads = 1024 |
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elif target.kind.name == "rocm": |
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threads = 256 |
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elif target.kind.name == "metal": |
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threads = 256 |
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else: |
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threads = 64 |
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results: List[Optional[int]] = [] |
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dynamic: List[int] = [] |
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for i, loop in enumerate(loops): |
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loop_extent = loop.extent |
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if isinstance(loop_extent, tir.IntImm): |
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loop_extent = loop_extent.value |
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extent = 1 |
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while extent <= loop_extent and extent <= threads: |
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extent *= 2 |
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extent //= 2 |
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assert extent >= 1 |
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assert threads % extent == 0 |
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threads //= extent |
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results.append(extent) |
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else: |
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results.append(None) |
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dynamic.append(i) |
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for i in dynamic: |
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extent = 1 |
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while extent <= max_threads_for_dynamic_loop and extent <= threads: |
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extent *= 2 |
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extent //= 2 |
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assert extent >= 1 |
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assert threads % extent == 0 |
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threads //= extent |
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results[i] = extent |
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if dynamic: |
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results[dynamic[0]] *= threads |
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return results |
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def get_sm_version(target: Target) -> int: |
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if target.kind.name != "cuda": |
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return -1 |
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arch = target.arch |
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sm_version = arch.replace("sm_", "") |
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return int(sm_version) if sm_version.isdigit() else -1 |
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