Make FlyDSL LDS checks architecture-aware and reduce tuner failure noise

aiter/ops/flydsl/gemm_kernels.py

@@ -19,15 +19,14 @@
 
 from ..shuffle import shuffle_weight
 from .kernels.splitk_hgemm import compile_hgemm_kernel
-from .utils import is_flydsl_available
+from .utils import get_shared_memory_per_block, is_flydsl_available
 
 __all__ = [
     "flydsl_hgemm",
 ]
 
 SPLIT_K_COUNTER_MAX_LEN = 128
 SPLIT_K_SIGNAL_STATE_COUNT = 3
-MAX_LDS_BYTES = 163840
 FIXED_STAGE = 2
 FIXED_C_TO_LDS = False
 KERNEL_ASYNC_COPY = get_rocm_arch() != "gfx942"
@@ -333,10 +332,11 @@ def _validate_hgemm_tiling(
         stages=stages,
         b_to_lds=b_to_lds,
     )
-    if lds_bytes > MAX_LDS_BYTES:
+    lds_limit = get_shared_memory_per_block(fallback_gfx=get_gfx())
+    if lds_bytes > lds_limit:
         raise ValueError(
             "Invalid tile combination: estimated LDS usage "
-            f"{lds_bytes} exceeds the hardware limit {MAX_LDS_BYTES}"
+            f"{lds_bytes} exceeds the hardware limit {lds_limit}"
         )
 
 

aiter/ops/flydsl/gemm_tune/flydsl_gemm_a8w8_bpreshuffle_common.py

@@ -4,6 +4,11 @@
 import math
 import os
 
+from aiter.ops.flydsl.utils import (
+    addressable_lds_bytes_for_gfx as _addressable_lds_bytes_for_gfx,
+    get_shared_memory_per_block,
+)
+
 
 def get_gfx():
     """Detect GPU arch: honour GPU_ARCHS env, fall back to chip_info, default gfx942."""
@@ -165,26 +170,13 @@ def kernel_instance_estimated_lds_bytes(ki: kernelInstance) -> int:
     )
 
 
-# Per-kernel LDS cap for tune filtering (must match LLVM AMDGPU
-# getAddressableLocalMemorySize for the compile target).
-# When arch cannot be parsed (no GPU, bad string), stay conservative for CDNA.
-_FALLBACK_MAX_LDS_BYTES = 65536
-
-
 def addressable_lds_bytes_for_gfx(gfx: str) -> int:
-    g = (gfx or "").strip().lower().split(":")[0]
-    if not g.startswith("gfx"):
-        return _FALLBACK_MAX_LDS_BYTES
-    if g.startswith("gfx950"):
-        return 163840
-    if g.startswith("gfx7") or g.startswith("gfx8"):
-        return 32768
-    return 65536
+    return _addressable_lds_bytes_for_gfx(gfx)
 
 
 def max_lds_bytes_for_tune() -> int:
-    """Addressable LDS limit for current target (from ``get_gfx()``)."""
-    return addressable_lds_bytes_for_gfx(get_gfx())
+    """Addressable LDS limit for current target."""
+    return get_shared_memory_per_block(fallback_gfx=get_gfx())
 
 
 # fmt: off
@@ -277,7 +269,7 @@ def _estimate_max_wpe(tile_m: int, tile_n: int, total_vgpr: int = 512) -> int:
 
     Preshuffle GEMM always uses 16x16 MFMA (4 VGPRs per thread per block).
     Per-thread accum VGPRs = round_up(tile_m, 16) * round_up(tile_n, 16) / 256.
-    Estimated total ≈ accum * 1.5 (pipeline overhead for A/B buffers).
+    Estimated total ? accum * 1.5 (pipeline overhead for A/B buffers).
     Returns the max waves_per_eu that the register file can support.
     """
     padded_m = math.ceil(tile_m / _MFMA_M) * _MFMA_M

aiter/ops/flydsl/kernels/splitk_hgemm.py

@@ -18,6 +18,7 @@
 from flydsl.utils.smem_allocator import SmemAllocator, SmemPtr
 
 from .tensor_shim import GTensor, STensor, _to_raw, get_dtype_in_kernel
+from ..utils import get_shared_memory_per_block
 
 SPLIT_K_COUNTER_MAX_LEN = 128
 SPLIT_K_SIGNAL_STATE_COUNT = 3
@@ -178,6 +179,15 @@ def compile_hgemm_kernel(
     assert BLOCK_MN_SIZE % BLOCK_VECS == 0
     BLOCK_K_BYTES = BLOCK_K * DTYPE_BYTES
 
+    KERNEL_NAME = f"hgemm_{dtype}_{BLOCK_M}x{BLOCK_N}x{BLOCK_K}_S{STAGES}TN"
+    KERNEL_NAME += "_NA" if not ASYNC_COPY else "_AS"
+    if B_PRE_SHUFFLE:
+        KERNEL_NAME += "_BP"
+    if IS_SPLIT_K:
+        KERNEL_NAME += f"_SPK{SPLIT_K}"
+    if B_TO_LDS:
+        KERNEL_NAME += "_BS"
+
     allocator = SmemAllocator(None, arch=GPU_ARCH, global_sym_name="smem")
     smem_a_offset = allocator._align(allocator.ptr, 16)
     AS_BYTES = STAGES * BLOCK_M * BLOCK_K * DTYPE_BYTES
@@ -188,22 +198,20 @@ def compile_hgemm_kernel(
         smem_b_offset = allocator._align(allocator.ptr, 16)
         allocator.ptr = smem_b_offset + STAGES * BLOCK_N * BLOCK_K * DTYPE_BYTES
         SMEM_USE += STAGES * BLOCK_N * BLOCK_K * DTYPE_BYTES
-    assert SMEM_USE <= 163840
+    smem_limit = get_shared_memory_per_block(fallback_gfx=GPU_ARCH)
+    if SMEM_USE > smem_limit:
+        raise RuntimeError(
+            f"{KERNEL_NAME} requires {SMEM_USE} bytes LDS, "
+            f"but device limit is {smem_limit} bytes "
+            f"(arch={GPU_ARCH}, TILE_M={TILE_M}, TILE_N={TILE_N}, TILE_K={TILE_K}, "
+            f"SPLIT_K={SPLIT_K}, B_TO_LDS={B_TO_LDS})",
+        )
     LDG_ASYNC_VEC_SIZE = DMA_BYTES // DTYPE_BYTES
     LDG_A_X_THREADS_AS = BLOCK_K // LDG_ASYNC_VEC_SIZE
     LDG_REG_A_COUNT_AS = BLOCK_MK_SIZE // LDG_ASYNC_VEC_SIZE // BLOCK_THREADS
     LDG_B_X_THREADS_AS = BLOCK_K // LDG_ASYNC_VEC_SIZE
     LDG_REG_B_COUNT_AS = BLOCK_NK_SIZE // LDG_ASYNC_VEC_SIZE // BLOCK_THREADS
 
-    KERNEL_NAME = f"hgemm_{dtype}_{BLOCK_M}x{BLOCK_N}x{BLOCK_K}_S{STAGES}TN"
-    KERNEL_NAME += "_NA" if not ASYNC_COPY else "_AS"
-    if B_PRE_SHUFFLE:
-        KERNEL_NAME += "_BP"
-    if IS_SPLIT_K:
-        KERNEL_NAME += f"_SPK{SPLIT_K}"
-    if B_TO_LDS:
-        KERNEL_NAME += "_BS"
-
     @flyc.kernel
     def hgemm_kernel(
         C: fx.Tensor,
@@ -925,9 +933,17 @@ def _launch(*args, **kwargs):
     def _compile(C, A, B, m, COUNTER, signal_state, stream):
         with CompilationContext.compile_hints(_compile_hints):
             if _compile_cache.get(m, None) is None:
-                _compile_cache[m] = flyc.compile(
-                    launch_hgemm_kernel, C, A, B, m, COUNTER, signal_state, stream
-                )
+                try:
+                    _compile_cache[m] = flyc.compile(
+                        launch_hgemm_kernel, C, A, B, m, COUNTER, signal_state, stream
+                    )
+                except Exception as e:
+                    raise RuntimeError(
+                        f"{KERNEL_NAME} failed "
+                        f"(arch={GPU_ARCH}, n={n}, k={k}, TILE_M={TILE_M}, TILE_N={TILE_N}, "
+                        f"TILE_K={TILE_K}, SPLIT_K={SPLIT_K}, B_TO_LDS={B_TO_LDS}, "
+                        f"SMEM_USE={SMEM_USE}, SMEM_LIMIT={smem_limit}): {e}",
+                    ) from e
             return _compile_cache[m]
 
     _launch.compile = _compile

aiter/ops/flydsl/utils.py

@@ -5,6 +5,37 @@
 
 import importlib.util
 
+import torch
+
+_FALLBACK_MAX_LDS_BYTES = 65536
+
+
+def addressable_lds_bytes_for_gfx(gfx: str) -> int:
+    g = (gfx or "").strip().lower().split(":")[0]
+    if not g.startswith("gfx"):
+        return _FALLBACK_MAX_LDS_BYTES
+    if g.startswith("gfx950"):
+        return 163840
+    if g.startswith("gfx7") or g.startswith("gfx8"):
+        return 32768
+    return 65536
+
+
+def get_shared_memory_per_block(device=None, fallback_gfx: str = "") -> int:
+    """Return per-block shared memory/LDS limit for the active device."""
+    try:
+        if device is None:
+            device = torch.cuda.current_device()
+        props = torch.cuda.get_device_properties(device)
+        shared_memory_per_block = int(getattr(props, "shared_memory_per_block", 0) or 0)
+        if shared_memory_per_block > 0:
+            return shared_memory_per_block
+        return addressable_lds_bytes_for_gfx(
+            getattr(props, "gcnArchName", fallback_gfx)
+        )
+    except Exception:
+        return addressable_lds_bytes_for_gfx(fallback_gfx)
+
 
 def is_flydsl_available() -> bool:
     return importlib.util.find_spec("flydsl") is not None

aiter/utility/base_tuner.py

@@ -443,13 +443,13 @@ def post_process(self, rets, args, topk=-1, fast_mode=False):
                     f"error: no valid candidate found for {info_key}, please check the result or errRatio in all result file running with --profile_file"
                 )
 
-            if len(filtered_time) < topk:
-                topk = len(filtered_time)
-                print(f"choose {topk} kernels")
-            self.topk = topk
+            effective_topk = min(topk, len(filtered_time))
+            if effective_topk < topk:
+                print(f"choose {effective_topk} kernels")
+            self.topk = effective_topk
             best_config = [
                 ((info_key, *info_ex), us, max_err_ratio)
-                for info_ex, us, max_err_ratio in filtered_time[0:topk]
+                for info_ex, us, max_err_ratio in filtered_time[0:effective_topk]
             ]
             if not best_config:
                 logger.info(f"No kernel can be used for {info_key}")

aiter/utility/mp_tuner.py

@@ -9,6 +9,14 @@
 from aiter import logger
 
 
+def _is_mapping_error(exc: BaseException) -> bool:
+    return isinstance(exc, KeyError)
+
+
+def _is_accelerator_error(exc: BaseException) -> bool:
+    return type(exc).__name__ == "AcceleratorError"
+
+
 def worker(
     gpu_id,
     info,
@@ -36,7 +44,7 @@ def worker(
             res, us = run_perftest(func, *args, **kwargs)
             us = round(us, 4)
 
-        except RuntimeError as e:
+        except (RuntimeError, ValueError) as e:
             print(f"run gpu func warning: info:{info}\t {e}", flush=True)
             us = -1  # not support or error
             max_err_ratio = 1.0
@@ -50,6 +58,8 @@ def worker(
         if us == 0:
             print(f"Warning: try run {max_retries} times, but still get 0!")
         torch.cuda.synchronize()
+        if us == -1 or res is None:
+            return info, us, round(max_err_ratio, 4)
         if ref is not None:
             if isinstance(ref, torch.Tensor):
                 ref = [ref]
@@ -448,14 +458,13 @@ def add_dummy_result(k, results_list):
             except Exception as e:
                 # Check if it's a process crash (segfault, memory fault, etc.)
                 error_type = type(e).__name__
-
-                # Special handling for KeyError (PID mapping issue)
-                is_mapping_error = error_type == "KeyError"
+                is_mapping_error = _is_mapping_error(e)
+                is_accelerator_error = _is_accelerator_error(e)
                 # not restart as this is not root use
                 if is_mapping_error:
                     error_msg = f"[Mapping Error] Task {k} - Process PID not in GPU map: {error_type} - {e}"
                     dummy_failed_tasks.append((k, "mapping error"))
-                elif error_type == "AcceleratorError":
+                elif is_accelerator_error:
                     # GPU fault (e.g. illegal memory access): worker returns exception instead of
                     # hanging. Unlike hang->timeout, the faulting worker may stay alive and accept
                     # more tasks on the same bad GPU. Break immediately to trigger restart and