drbh
commited on
Commit
Β·
56449c1
1
Parent(s):
09eec95
feat: bump api on readme
Browse files- README.md +8 -14
- scripts/readme_example.py +3 -8
README.md
CHANGED
@@ -30,8 +30,6 @@ torch.manual_seed(42)
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flash_attn = get_kernel("kernels-community/flash-attn")
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device = torch.device("cuda")
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-
print("Flash Attention functions:", [i for i in dir(flash_attn) if i.startswith("mha")])
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-
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# Create test tensors
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B, S, H, D = 2, 5, 4, 8 # batch, seq_len, heads, head_dim
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q = k = v = torch.randn(B, S, H, D, device=device, dtype=torch.float16)
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@@ -46,12 +44,11 @@ def reference_attention(query, key, value, causal=False):
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# 1. Standard attention
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print("\n1. Standard attention:")
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out_ref = reference_attention(q, k, v)
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-
out_flash = flash_attn.
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q=q,
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k=k,
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v=v,
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is_causal=False,
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-
softmax_scale=1.0 / (D ** 0.5), # scale factor
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)[0]
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print(f"Reference output: {out_ref.shape}")
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print(f"Flash output: {out_flash.shape}")
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@@ -61,12 +58,11 @@ print(f"Outputs close: {torch.allclose(out_flash, out_ref, atol=1e-2, rtol=1e-3)
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print("\n2. Causal attention:")
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out_ref_causal = reference_attention(q, k, v, causal=True)
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-
out_causal = flash_attn.
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q=q,
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k=k,
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v=v,
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is_causal=True,
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-
softmax_scale=1.0 / (D ** 0.5), # scale factor
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)[0]
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print(f"Reference causal output: {out_ref_causal.shape}")
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print(f"Flash causal output: {out_causal.shape}")
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@@ -74,7 +70,7 @@ print(f"Outputs close: {torch.allclose(out_causal, out_ref_causal, atol=1e-2, rt
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def var_reference_attention(q, k, v, cu_seqlens_q, cu_seqlens_k, max_seqlen_q, max_seqlen_k, causal=False):
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batch_size = cu_seqlens_q.shape[0] - 1
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# Return output in packed format
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total_tokens_q = q.shape[0]
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out = torch.zeros((total_tokens_q, q.shape[1], q.shape[2]), device=q.device, dtype=q.dtype)
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@@ -111,7 +107,7 @@ cu_k = torch.tensor([0, 4, 9, 12], device=device, dtype=torch.int32)
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out_var_ref = var_reference_attention(q_var, k_var, v_var, cu_q, cu_k, max_seqlen_q=4, max_seqlen_k=5, causal=False)
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# Custom function to handle variable
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-
out_var = flash_attn.
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q=q_var,
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k=k_var,
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v=v_var,
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@@ -119,7 +115,6 @@ out_var = flash_attn.mha_varlen_fwd(
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cu_seqlens_k=cu_k,
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max_seqlen_q=4,
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max_seqlen_k=5,
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softmax_scale=1.0 / (D ** 0.5), # scale factor
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)[0]
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print(f"Variable length output: {out_var.shape}")
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print(f"Reference variable length output: {out_var_ref.shape}")
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@@ -133,21 +128,20 @@ uv run scripts/readme_example.py
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```
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```txt
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Reading inline script metadata from `
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Fetching
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Flash Attention functions: ['mha_bwd', 'mha_fwd', 'mha_fwd_kvcache', 'mha_varlen_bwd', 'mha_varlen_fwd']
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1. Standard attention:
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Reference output: torch.Size([2, 5, 4, 8])
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Flash output: torch.Size([2, 5, 4, 8])
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Outputs close: True
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-
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Reference causal output: torch.Size([2, 5, 4, 8])
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Flash causal output: torch.Size([2, 5, 4, 8])
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Outputs close: True
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-
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Variable length output: torch.Size([10, 4, 8])
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Reference variable length output: torch.Size([10, 4, 8])
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Outputs close: True
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flash_attn = get_kernel("kernels-community/flash-attn")
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device = torch.device("cuda")
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# Create test tensors
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B, S, H, D = 2, 5, 4, 8 # batch, seq_len, heads, head_dim
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q = k = v = torch.randn(B, S, H, D, device=device, dtype=torch.float16)
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# 1. Standard attention
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print("\n1. Standard attention:")
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out_ref = reference_attention(q, k, v)
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+
out_flash = flash_attn.fwd(
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q=q,
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k=k,
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v=v,
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is_causal=False,
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)[0]
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print(f"Reference output: {out_ref.shape}")
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print(f"Flash output: {out_flash.shape}")
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print("\n2. Causal attention:")
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out_ref_causal = reference_attention(q, k, v, causal=True)
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out_causal = flash_attn.fwd(
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q=q,
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k=k,
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v=v,
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is_causal=True,
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)[0]
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print(f"Reference causal output: {out_ref_causal.shape}")
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print(f"Flash causal output: {out_causal.shape}")
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def var_reference_attention(q, k, v, cu_seqlens_q, cu_seqlens_k, max_seqlen_q, max_seqlen_k, causal=False):
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batch_size = cu_seqlens_q.shape[0] - 1
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# Return output in packed format (same as flash attention)
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total_tokens_q = q.shape[0]
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out = torch.zeros((total_tokens_q, q.shape[1], q.shape[2]), device=q.device, dtype=q.dtype)
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out_var_ref = var_reference_attention(q_var, k_var, v_var, cu_q, cu_k, max_seqlen_q=4, max_seqlen_k=5, causal=False)
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# Custom function to handle variable
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out_var = flash_attn.varlen_fwd(
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q=q_var,
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k=k_var,
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v=v_var,
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cu_seqlens_k=cu_k,
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max_seqlen_q=4,
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max_seqlen_k=5,
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)[0]
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print(f"Variable length output: {out_var.shape}")
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print(f"Reference variable length output: {out_var_ref.shape}")
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```
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```txt
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+
Reading inline script metadata from `scripts/readme_example.py`
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+
Fetching 20 files: 100%|ββββββββββββββββββββββββββββββββββββββββββββββββββ| 20/20 [00:00<00:00, 16371.21it/s]
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1. Standard attention:
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Reference output: torch.Size([2, 5, 4, 8])
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Flash output: torch.Size([2, 5, 4, 8])
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Outputs close: True
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+
2. Causal attention:
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Reference causal output: torch.Size([2, 5, 4, 8])
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Flash causal output: torch.Size([2, 5, 4, 8])
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Outputs close: True
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+
3. Variable length sequences:
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Variable length output: torch.Size([10, 4, 8])
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Reference variable length output: torch.Size([10, 4, 8])
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Outputs close: True
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scripts/readme_example.py
CHANGED
@@ -13,8 +13,6 @@ torch.manual_seed(42)
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flash_attn = get_kernel("kernels-community/flash-attn")
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device = torch.device("cuda")
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print("Flash Attention functions:", [i for i in dir(flash_attn) if i.startswith("mha")])
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-
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# Create test tensors
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B, S, H, D = 2, 5, 4, 8 # batch, seq_len, heads, head_dim
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q = k = v = torch.randn(B, S, H, D, device=device, dtype=torch.float16)
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@@ -29,12 +27,11 @@ def reference_attention(query, key, value, causal=False):
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# 1. Standard attention
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print("\n1. Standard attention:")
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out_ref = reference_attention(q, k, v)
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-
out_flash = flash_attn.
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q=q,
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k=k,
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v=v,
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is_causal=False,
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-
softmax_scale=1.0 / (D ** 0.5), # scale factor
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)[0]
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print(f"Reference output: {out_ref.shape}")
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print(f"Flash output: {out_flash.shape}")
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@@ -44,12 +41,11 @@ print(f"Outputs close: {torch.allclose(out_flash, out_ref, atol=1e-2, rtol=1e-3)
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print("\n2. Causal attention:")
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out_ref_causal = reference_attention(q, k, v, causal=True)
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out_causal = flash_attn.
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q=q,
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k=k,
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v=v,
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is_causal=True,
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-
softmax_scale=1.0 / (D ** 0.5), # scale factor
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)[0]
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print(f"Reference causal output: {out_ref_causal.shape}")
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print(f"Flash causal output: {out_causal.shape}")
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@@ -94,7 +90,7 @@ cu_k = torch.tensor([0, 4, 9, 12], device=device, dtype=torch.int32)
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out_var_ref = var_reference_attention(q_var, k_var, v_var, cu_q, cu_k, max_seqlen_q=4, max_seqlen_k=5, causal=False)
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# Custom function to handle variable
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out_var = flash_attn.
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q=q_var,
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k=k_var,
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v=v_var,
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@@ -102,7 +98,6 @@ out_var = flash_attn.mha_varlen_fwd(
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cu_seqlens_k=cu_k,
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max_seqlen_q=4,
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max_seqlen_k=5,
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softmax_scale=1.0 / (D ** 0.5), # scale factor
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)[0]
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print(f"Variable length output: {out_var.shape}")
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print(f"Reference variable length output: {out_var_ref.shape}")
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flash_attn = get_kernel("kernels-community/flash-attn")
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device = torch.device("cuda")
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# Create test tensors
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B, S, H, D = 2, 5, 4, 8 # batch, seq_len, heads, head_dim
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q = k = v = torch.randn(B, S, H, D, device=device, dtype=torch.float16)
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# 1. Standard attention
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print("\n1. Standard attention:")
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out_ref = reference_attention(q, k, v)
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+
out_flash = flash_attn.fwd(
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q=q,
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k=k,
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v=v,
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is_causal=False,
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)[0]
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print(f"Reference output: {out_ref.shape}")
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print(f"Flash output: {out_flash.shape}")
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print("\n2. Causal attention:")
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out_ref_causal = reference_attention(q, k, v, causal=True)
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+
out_causal = flash_attn.fwd(
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q=q,
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k=k,
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v=v,
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is_causal=True,
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)[0]
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print(f"Reference causal output: {out_ref_causal.shape}")
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print(f"Flash causal output: {out_causal.shape}")
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out_var_ref = var_reference_attention(q_var, k_var, v_var, cu_q, cu_k, max_seqlen_q=4, max_seqlen_k=5, causal=False)
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# Custom function to handle variable
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+
out_var = flash_attn.varlen_fwd(
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q=q_var,
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k=k_var,
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v=v_var,
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cu_seqlens_k=cu_k,
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max_seqlen_q=4,
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max_seqlen_k=5,
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)[0]
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print(f"Variable length output: {out_var.shape}")
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print(f"Reference variable length output: {out_var_ref.shape}")
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