h3-blackwell-runtime/tools/profile_sage2_scheduler.py

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"""Profile exact SageAttention2 preparation, mainloop, and tail scheduling on real H3 tensors."""
from __future__ import annotations
import argparse
import hashlib
import json
import math
from pathlib import Path
import torch
from h3_blackwell_runtime.sage2_entry import prepare_v
from profile_attention_path import prepare_qkv, representative_attention_inputs, summarize
CTA_Q = 128
CTA_K = 64
WARP_Q = 32
WARP_K = 64
V_SCALE_MAX = 2.25
def tensor_sha256(value: torch.Tensor) -> str:
host_bytes = value.detach().contiguous().view(torch.uint8).cpu().numpy()
return hashlib.sha256(memoryview(host_bytes)).hexdigest()
def event_measure(fn, *, warmup: int, iterations: int):
for _ in range(warmup):
fn()
torch.cuda.synchronize()
values = []
result = None
for _ in range(iterations):
started = torch.cuda.Event(enable_timing=True)
finished = torch.cuda.Event(enable_timing=True)
started.record()
result = fn()
finished.record()
finished.synchronize()
values.append(started.elapsed_time(finished) / 1000.0)
return summarize(values), result
def quantize_qk(q: torch.Tensor, k: torch.Tensor, km: torch.Tensor):
import sageattention.core as sage_core
return sage_core.per_warp_int8_cuda(
q,
k,
km,
BLKQ=CTA_Q,
WARPQ=WARP_Q,
BLKK=CTA_K,
tensor_layout="NHD",
)
def quantize_v(v: torch.Tensor):
import sageattention.core as sage_core
return sage_core.per_channel_fp8(
v,
tensor_layout="NHD",
scale_max=V_SCALE_MAX,
smooth_v=False,
)
def run_mainloop(
q_int8: torch.Tensor,
k_int8: torch.Tensor,
v_fp8: torch.Tensor,
q_scale: torch.Tensor,
k_scale: torch.Tensor,
v_scale: torch.Tensor,
output: torch.Tensor,
) -> torch.Tensor:
import sageattention.core as sage_core
sage_core.sm89_compile.qk_int8_sv_f8_accum_f16_fuse_v_scale_attn_inst_buf(
q_int8,
k_int8,
v_fp8,
output,
q_scale,
k_scale,
v_scale,
0,
0,
2,
output.shape[-1] ** -0.5,
0,
)
return output
def prepare_quantized(q: torch.Tensor, k: torch.Tensor, v: torch.Tensor):
km = k.mean(dim=1, keepdim=True)
q_int8, q_scale, k_int8, k_scale = quantize_qk(q, k, km)
v_fp8, v_scale, _ = quantize_v(v)
output = torch.empty(q.shape, dtype=q.dtype, device=q.device)
return km, q_int8, q_scale, k_int8, k_scale, v_fp8, v_scale, output
def tail_row(
q: torch.Tensor,
k: torch.Tensor,
v: torch.Tensor,
*,
warmup: int,
iterations: int,
) -> dict:
quantized = prepare_quantized(q, k, v)
_, q_int8, q_scale, k_int8, k_scale, v_fp8, v_scale, output = quantized
timing, result = event_measure(
lambda: run_mainloop(
q_int8, k_int8, v_fp8, q_scale, k_scale, v_scale, output,
),
warmup=warmup,
iterations=iterations,
)
q_len = q.shape[1]
kv_len = k.shape[1]
q_ctas = math.ceil(q_len / CTA_Q)
k_iterations = math.ceil(kv_len / CTA_K)
return {
"q_len": q_len,
"kv_len": kv_len,
"q_ctas_per_head": q_ctas,
"k_iterations_per_cta": k_iterations,
"q_tail_rows": q_len % CTA_Q,
"k_tail_rows": kv_len % CTA_K,
"scheduled_q_rows": q_ctas * CTA_Q,
"q_row_efficiency": q_len / (q_ctas * CTA_Q),
"mainloop": timing,
"checksum": result.float().sum().item(),
}
def difference(actual: torch.Tensor, expected: torch.Tensor) -> dict:
delta = actual.float() - expected.float()
return {
"equal": torch.equal(actual, expected),
"max_abs": delta.abs().max().item(),
"mean_abs": delta.abs().mean().item(),
}
def parse_args() -> argparse.Namespace:
parser = argparse.ArgumentParser(description=__doc__)
parser.add_argument("--model-path", default="/models/minimax_h3_fl2va_pruned_nvfp4.safetensors")
parser.add_argument("--output", type=Path, required=True)
parser.add_argument("--width", type=int, default=1344)
parser.add_argument("--height", type=int, default=768)
parser.add_argument("--frames", type=int, default=124)
parser.add_argument("--steps", type=int, default=12)
parser.add_argument("--sampler-step", type=int, default=1)
parser.add_argument("--seed", type=int, default=440420)
parser.add_argument("--text-tokens", type=int, default=100)
parser.add_argument("--block-index", type=int, default=24)
parser.add_argument("--attention", default="sage2", choices=("sage2",))
parser.add_argument("--warmup", type=int, default=3)
parser.add_argument("--iterations", type=int, default=10)
parser.add_argument("--tail-iterations", type=int, default=5)
parser.add_argument("--skip-tail-study", action="store_true")
parser.add_argument("--cuda-profiler-capture", action="store_true")
parser.add_argument("--expected-output-sha256")
parser.add_argument("--device", default="cuda")
return parser.parse_args()
def main() -> None:
args = parse_args()
block, hidden, rotation, _segments, metadata = representative_attention_inputs(args)
with torch.inference_mode():
q, k, v, _ = prepare_qkv(block, hidden, rotation, None)
km_timing, km = event_measure(
lambda: k.mean(dim=1, keepdim=True),
warmup=args.warmup,
iterations=args.iterations,
)
qk_timing, qk = event_measure(
lambda: quantize_qk(q, k, km),
warmup=args.warmup,
iterations=args.iterations,
)
q_int8, q_scale, k_int8, k_scale = qk
import sageattention.core as sage_core
import sageattention.quant as sage_quant
q_int8_probe = torch.empty(q.shape, dtype=torch.int8, device=q.device)
q_scale_probe = torch.empty_like(q_scale)
q_quant_timing, _ = event_measure(
lambda: sage_quant._fused.quant_per_warp_int8_cuda(
q, q_int8_probe, q_scale_probe, CTA_Q, WARP_Q, 0,
),
warmup=args.warmup,
iterations=args.iterations,
)
k_int8_probe = torch.empty(k.shape, dtype=torch.int8, device=k.device)
k_scale_probe = torch.empty_like(k_scale)
k_quant_timing, _ = event_measure(
lambda: sage_quant._fused.quant_per_block_int8_fuse_sub_mean_cuda(
k, km.squeeze(1), k_int8_probe, k_scale_probe, CTA_K, 0,
),
warmup=args.warmup,
iterations=args.iterations,
)
padded_k = math.ceil(v.shape[1] / CTA_K) * CTA_K
v_transposed = torch.empty(
(v.shape[0], v.shape[3], v.shape[2], padded_k),
dtype=v.dtype,
device=v.device,
)
v_transpose_timing, _ = event_measure(
lambda: sage_quant._fused.transpose_pad_permute_cuda(v, v_transposed, 0),
warmup=args.warmup,
iterations=args.iterations,
)
v_fp8_probe = torch.empty_like(v_transposed, dtype=torch.float8_e4m3fn)
v_scale_probe = torch.empty(
(v.shape[0], v.shape[2], v.shape[3]),
dtype=torch.float32,
device=v.device,
)
v_scale_quant_timing, _ = event_measure(
lambda: sage_quant._fused.scale_fuse_quant_cuda(
v_transposed, v_fp8_probe, v_scale_probe, v.shape[1], V_SCALE_MAX, 0,
),
warmup=args.warmup,
iterations=args.iterations,
)
v_timing, vq = event_measure(
lambda: quantize_v(v),
warmup=args.warmup,
iterations=args.iterations,
)
v_fp8, v_scale, _ = vq
candidate_v_timing, candidate_vq = event_measure(
lambda: prepare_v(v, scale_max=V_SCALE_MAX),
warmup=args.warmup,
iterations=args.iterations,
)
candidate_v_fp8, candidate_v_scale = candidate_vq
output = torch.empty(q.shape, dtype=q.dtype, device=q.device)
mainloop_fn = lambda: run_mainloop(
q_int8, k_int8, v_fp8, q_scale, k_scale, v_scale, output,
)
if args.cuda_profiler_capture:
for _ in range(args.warmup):
mainloop_fn()
torch.cuda.synchronize()
torch.cuda.cudart().cudaProfilerStart()
captured = mainloop_fn()
torch.cuda.synchronize()
torch.cuda.cudart().cudaProfilerStop()
report = {
"metadata": metadata,
"capture": "one unchanged prequantized Sage2 mainloop",
"q_shape": list(q.shape),
"k_shape": list(k.shape),
"v_shape": list(v.shape),
"checksum": captured.float().sum().item(),
"scheduler": {
"cta_q": CTA_Q,
"cta_k": CTA_K,
"warp_q": WARP_Q,
"warp_k": WARP_K,
"warps_per_cta": 4,
"threads_per_cta": 128,
"dynamic_shared_memory_bytes": 32768,
"q_ctas_per_head": math.ceil(q.shape[1] / CTA_Q),
"heads": q.shape[2],
"grid_ctas": math.ceil(q.shape[1] / CTA_Q) * q.shape[2] * q.shape[0],
"k_iterations_per_cta": math.ceil(k.shape[1] / CTA_K),
"explicit_pipeline_stages": 2,
},
}
args.output.parent.mkdir(parents=True, exist_ok=True)
args.output.write_text(json.dumps(report, indent=2) + "\n", encoding="utf-8")
print(json.dumps(report, indent=2), flush=True)
return
mainloop_timing, manual_output = event_measure(
mainloop_fn,
warmup=args.warmup,
iterations=args.iterations,
)
candidate_output = torch.empty_like(output)
run_mainloop(
q_int8,
k_int8,
candidate_v_fp8,
q_scale,
k_scale,
candidate_v_scale,
candidate_output,
)
torch.cuda.synchronize()
reference = __import__("sageattention").sageattn(
q, k, v, tensor_layout="NHD", is_causal=False, smooth_k=False,
)
torch.cuda.synchronize()
output_sha256 = tensor_sha256(manual_output)
expected_output_matches = (
args.expected_output_sha256 is None
or output_sha256 == args.expected_output_sha256
)
tail_study = []
if not args.skip_tail_study:
q_lengths = sorted({
(q.shape[1] // CTA_Q) * CTA_Q,
(q.shape[1] // CTA_Q) * CTA_Q + 1,
q.shape[1],
})
kv_lengths = sorted({
(k.shape[1] // CTA_K) * CTA_K,
(k.shape[1] // CTA_K) * CTA_K + 1,
k.shape[1],
})
for q_len in q_lengths:
tail_study.append({
"sweep": "q_tail_fixed_kv",
**tail_row(
q[:, :q_len], k, v,
warmup=args.warmup,
iterations=args.tail_iterations,
),
})
for kv_len in kv_lengths:
tail_study.append({
"sweep": "kv_tail_fixed_q",
**tail_row(
q, k[:, :kv_len], v[:, :kv_len],
warmup=args.warmup,
iterations=args.tail_iterations,
),
})
report = {
"metadata": metadata,
"q_shape": list(q.shape),
"k_shape": list(k.shape),
"v_shape": list(v.shape),
"warmup": args.warmup,
"iterations": args.iterations,
"phase_timings": {
"k_mean_and_smoothing_preparation": km_timing,
"qk_int8_quantization": qk_timing,
"q_int8_quantization": q_quant_timing,
"k_int8_subtract_mean_quantization": k_quant_timing,
"v_fp8_transpose_scale_quantization": v_timing,
"v_transpose_pad_permute": v_transpose_timing,
"v_scale_fp8_quantization": v_scale_quant_timing,
"vortex_direct_v_fp8_preparation": candidate_v_timing,
"fused_mainloop": mainloop_timing,
},
"fused_mainloop_phases": {
"int8_qk": "fused inside qk_int_sv_f8_attn_kernel",
"scale_application": "fused inside qk_int_sv_f8_attn_kernel",
"online_softmax": "fused inside qk_int_sv_f8_attn_kernel",
"pv_accumulation": "fused inside qk_int_sv_f8_attn_kernel",
"final_normalization_and_output": "fused inside qk_int_sv_f8_attn_kernel",
"timing_policy": "Do not assign independent wall time without changing the exact kernel schedule; use source-correlated hardware counters.",
},
"scheduler": {
"cta_q": CTA_Q,
"cta_k": CTA_K,
"warp_q": WARP_Q,
"warp_k": WARP_K,
"warps_per_cta": 4,
"threads_per_cta": 128,
"dynamic_shared_memory_bytes": 32768,
"q_ctas_per_head": math.ceil(q.shape[1] / CTA_Q),
"heads": q.shape[2],
"grid_ctas": math.ceil(q.shape[1] / CTA_Q) * q.shape[2] * q.shape[0],
"k_iterations_per_cta": math.ceil(k.shape[1] / CTA_K),
"q_tail_rows": q.shape[1] % CTA_Q,
"k_tail_rows": k.shape[1] % CTA_K,
"explicit_pipeline_stages": 2,
},
"manual_decomposition_vs_public_sage2": difference(manual_output, reference),
"vortex_v_fp8_vs_sage2": difference(candidate_v_fp8, v_fp8),
"vortex_v_scale_vs_sage2": difference(candidate_v_scale, v_scale),
"vortex_v_mainloop_vs_sage2": difference(candidate_output, manual_output),
"manual_checksum": manual_output.float().sum().item(),
"reference_checksum": reference.float().sum().item(),
"output_sha256": output_sha256,
"expected_output_sha256": args.expected_output_sha256,
"expected_output_matches": expected_output_matches,
"tail_study": tail_study,
}
args.output.parent.mkdir(parents=True, exist_ok=True)
args.output.write_text(json.dumps(report, indent=2) + "\n", encoding="utf-8")
print(json.dumps(report, indent=2), flush=True)
if not expected_output_matches:
raise RuntimeError(
f"output SHA256 mismatch: expected {args.expected_output_sha256}, got {output_sha256}"
)
if __name__ == "__main__":
main()