[Example] Add Split-K and Stream-K Examples and move MLA from fld to …

…mla (#110)

* Add DeepSeek MLA decode example with Flash Attention implementation

* Add GEMM SplitK and StreamK example implementations

This commit introduces two new example scripts demonstrating advanced GEMM (matrix multiplication) techniques:
- `example_tilelang_gemm_splitk.py`: Implements a Split-K GEMM kernel using TileLang
- `example_tilelang_gemm_streamk.py`: Implements a Stream-K GEMM kernel using TileLang

Both examples showcase different parallel computation strategies for matrix multiplication, with comprehensive testing using PyTorch reference implementations.

* Refactor GEMM SplitK and StreamK example implementations

Clean up and improve code formatting for the SplitK and StreamK GEMM example scripts:
- Remove unused import (Profiler) in splitk example
- Simplify line breaks and improve code readability
- Standardize indentation and remove unnecessary whitespace
- Optimize atomic add and copy operations for better clarity

examples/deepseek_mla/example_mla_decode.py

@@ -0,0 +1,267 @@
+import torch
+import torch.nn.functional as F
+import tilelang
+from tilelang.autotuner import *
+import tilelang.language as T
+
+num_split = 4
+
+
+def flashattn(batch, heads, kv_head_num, seqlen_kv, dim, pe_dim, block_N, block_H):
+    scale = (1.0 / (dim + pe_dim))**0.5 * 1.44269504  # log2(e)
+    shape_q = [batch, heads, (dim + pe_dim)]
+    shape_k = [batch, seqlen_kv, kv_head_num, (dim + pe_dim)]
+    shape_v = [batch, seqlen_kv, kv_head_num, dim]
+    shape_o = [batch, heads, dim]
+    part_shape = [batch, heads, num_split, dim]
+    dtype = "float16"
+    accum_dtype = "float"
+    kv_group_num = heads // kv_head_num
+    VALID_BLOCK_H = min(block_H, kv_group_num)
+    assert kv_head_num == 1, "kv_head_num must be 1"
+
+    @T.macro
+    def flash_attn_split(
+            Q: T.Buffer(shape_q, dtype),
+            K: T.Buffer(shape_k, dtype),
+            V: T.Buffer(shape_v, dtype),
+            glse: T.Buffer([batch, heads, num_split], dtype),
+            Output_partial: T.Buffer(part_shape, dtype),
+    ):
+        with T.Kernel(
+                batch, heads // min(block_H, kv_group_num), num_split, threads=128) as (bx, by, bz):
+            Q_shared = T.alloc_shared([block_H, (dim + pe_dim)], dtype)
+            K_shared = T.alloc_shared([block_N, (dim + pe_dim)], dtype)
+            V_shared = T.alloc_shared([block_N, dim], dtype)
+            O_shared = T.alloc_shared([block_H, dim], dtype)
+            acc_s = T.alloc_fragment([block_H, block_N], accum_dtype)
+            acc_s_cast = T.alloc_fragment([block_H, block_N], dtype)
+            acc_o = T.alloc_fragment([block_H, dim], accum_dtype)
+            scores_max = T.alloc_fragment([block_H], accum_dtype)
+            scores_max_prev = T.alloc_fragment([block_H], accum_dtype)
+            scores_scale = T.alloc_fragment([block_H], accum_dtype)
+            scores_sum = T.alloc_fragment([block_H], accum_dtype)
+            logsum = T.alloc_fragment([block_H], accum_dtype)
+
+            bid = bx
+            hid = by
+            sid = bz
+            cur_kv_head = hid // (kv_group_num // block_H)
+
+            T.annotate_layout({
+                O_shared: tilelang.layout.make_swizzled_layout(O_shared),
+            })
+
+            T.copy(Q[bid, hid * VALID_BLOCK_H:(hid + 1) * VALID_BLOCK_H, :], Q_shared)
+            T.fill(acc_o, 0)
+            T.fill(logsum, 0)
+            T.fill(scores_max, -T.infinity(accum_dtype))
+
+            loop_range = T.ceildiv((seqlen_kv // num_split), block_N)
+            for k in T.Pipelined(loop_range, num_stages=1):
+                T.copy(
+                    K[bid, (seqlen_kv // num_split) * sid +
+                      k * block_N:(seqlen_kv // num_split) * sid + (k + 1) * block_N,
+                      cur_kv_head, :], K_shared)
+                T.clear(acc_s)
+                T.gemm(Q_shared, K_shared, acc_s, transpose_B=True, policy=T.GemmWarpPolicy.FullRow)
+                T.copy(scores_max, scores_max_prev)
+                T.fill(scores_max, -T.infinity(accum_dtype))
+                T.reduce_max(acc_s, scores_max, dim=1, clear=False)
+                for i in T.Parallel(block_H):
+                    scores_scale[i] = T.exp2(scores_max_prev[i] * scale - scores_max[i] * scale)
+                for i, j in T.Parallel(block_H, block_N):
+                    acc_s[i, j] = T.exp2(acc_s[i, j] * scale - scores_max[i] * scale)
+                T.reduce_sum(acc_s, scores_sum, dim=1)
+                for i in T.Parallel(block_H):
+                    logsum[i] = logsum[i] * scores_scale[i] + scores_sum[i]
+                T.copy(acc_s, acc_s_cast)
+                for i, j in T.Parallel(block_H, dim):
+                    acc_o[i, j] *= scores_scale[i]
+                T.copy(
+                    V[bid, (seqlen_kv // num_split) * sid +
+                      k * block_N:(seqlen_kv // num_split) * sid + (k + 1) * block_N,
+                      cur_kv_head, :], V_shared)
+                T.gemm(acc_s_cast, V_shared, acc_o, policy=T.GemmWarpPolicy.FullRow)
+            for i, j in T.Parallel(block_H, dim):
+                acc_o[i, j] /= logsum[i]
+            for i in T.Parallel(block_H):
+                logsum[i] = T.log2(logsum[i]) + scores_max[i] * scale
+
+            T.copy(logsum, glse[bid, hid * VALID_BLOCK_H:(hid + 1) * VALID_BLOCK_H, sid])
+            T.copy(acc_o, O_shared)
+            T.copy(O_shared, Output_partial[bid, hid * VALID_BLOCK_H:(hid + 1) * VALID_BLOCK_H,
+                                            sid, :])
+
+    @T.macro
+    def combine(
+            glse: T.Buffer([batch, heads, num_split], dtype),
+            Output_partial: T.Buffer(part_shape, dtype),
+            Output: T.Buffer(shape_o, dtype),
+    ):
+        with T.Kernel(heads, batch, threads=128) as (by, bz):
+            po_local = T.alloc_fragment([dim], dtype)
+            o_accum_local = T.alloc_fragment([dim], accum_dtype)
+            lse_local = T.alloc_fragment([num_split, 1], dtype)
+            lse_local_split = T.alloc_local([1], accum_dtype)
+            lse_logsum_local = T.alloc_local([1], accum_dtype)
+            lse_max_local = T.alloc_fragment([1], accum_dtype)
+            scale_local = T.alloc_local([1], accum_dtype)
+
+            T.annotate_layout({
+                lse_logsum_local: T.Fragment(lse_logsum_local.shape, forward_thread_fn=lambda i: i),
+            })
+
+            T.clear(lse_logsum_local)
+            T.clear(o_accum_local)
+            for k in T.Parallel(num_split):
+                lse_local[k, 0] = glse[bz, by, k]
+            T.reduce_max(lse_local, lse_max_local, dim=0, clear=True)
+            for k in T.Pipelined(num_split, num_stages=1):
+                lse_local_split[0] = glse[bz, by, k]
+                lse_logsum_local[0] += T.exp2(lse_local_split[0] - lse_max_local[0])
+            lse_logsum_local[0] = T.log2(lse_logsum_local[0]) + lse_max_local[0]
+            for k in T.serial(num_split):
+                for i in T.Parallel(dim):
+                    po_local[i] = Output_partial[bz, by, k, i]
+                lse_local_split[0] = glse[bz, by, k]
+                scale_local[0] = T.exp2(lse_local_split[0] - lse_logsum_local[0])
+                for i in T.Parallel(dim):
+                    o_accum_local[i] += po_local[i] * scale_local[0]
+            for i in T.Parallel(dim):
+                Output[bz, by, i] = o_accum_local[i]
+
+    @T.prim_func
+    def main(
+            Q: T.Buffer(shape_q, dtype),
+            K: T.Buffer(shape_k, dtype),
+            V: T.Buffer(shape_v, dtype),
+            glse: T.Buffer([batch, heads, num_split], dtype),
+            Output_partial: T.Buffer(part_shape, dtype),  # [batch, heads, num_split, dim]
+            Output: T.Buffer(shape_o, dtype),
+    ):
+        flash_attn_split(Q, K, V, glse, Output_partial)
+        combine(glse, Output_partial, Output)
+
+    return main
+
+
+def ref_program(query, key, value, glse, Output_partial):
+    #     """
+    #     Inputs:
+    #     - query (Tensor): [batch, heads, dim]
+    #     - key (Tensor): [batch, seqlen_kv, kv_head_num, dim]
+    #     - value (Tensor): [batch, seqlen_kv, kv_head_num, dim]
+
+    #     Outputs:
+    #     - output (Tensor): [batch, heads, dim]
+    #     """
+    from einops import rearrange
+    batch_size, query_heads, dim = query.shape  # [batch_size, query_heads, dim]
+    _, seqlen_kv, kv_heads, _ = key.shape  # [batch_size, seqlen_kv, kv_heads, kv_dim]
+    dim_v = value.shape[-1]
+    assert kv_heads == 1, "kv_heads must be 1"
+
+    query_expanded = rearrange(query, 'b h d -> b h 1 d')  # [batch_size, query_heads, 1, dim]
+    key_expanded = key.expand(-1, -1, query_heads, -1)  # [batch_size, query_heads, seqlen_kv, dim]
+    value_expanded = value.expand(-1, -1, query_heads,
+                                  -1)  # [batch_size, query_heads, seqlen_kv, dim]
+    key_expanded = rearrange(key_expanded,
+                             'b n h d -> b h n d')  # [batch_size, kv_head_num, seqlen_kv, dim]
+    value_expanded = rearrange(value_expanded,
+                               'b n h d -> b h n d')  # [batch_size, query_heads, seqlen_kv, dim]
+
+    scores = torch.matmul(query_expanded,
+                          key_expanded.transpose(-1, -2))  # [batch_size, query_heads, 1, seqlen_kv]
+    scores = scores / torch.sqrt(torch.tensor(dim, dtype=scores.dtype))
+    attention_weights = F.softmax(scores, dim=-1)  # [batch_size, query_heads, 1, seqlen_kv]
+    output = torch.matmul(attention_weights, value_expanded)  # [batch_size, query_heads, 1, dim]
+    return output.view(batch_size, query_heads, dim_v)
+
+
+def flash_split_ref(Q, K, V):
+    dim = 512
+    pe_dim = 64
+    batch = Q.size(0)
+    nheads = Q.size(1)
+    assert Q.size(2) == dim + pe_dim, "dim must be 576=512+64"
+    block_N = 32
+    seqlen_kv = K.size(1)
+
+    scale = (1.0 / (dim + pe_dim))**0.5 * 1.44269504  # log2(e)
+    acc_s = torch.empty((batch, nheads, block_N), device="cuda", dtype=torch.float)
+    acc_s_cast = torch.empty((batch, nheads, block_N), device="cuda", dtype=torch.float16)
+    acc_o = torch.empty((batch, nheads, dim), device="cuda", dtype=torch.float)
+    scores_max = torch.empty((batch, nheads), device="cuda", dtype=torch.float)
+    scores_max_prev = torch.empty((batch, nheads), device="cuda", dtype=torch.float)
+    scores_scale = torch.empty((batch, nheads), device="cuda", dtype=torch.float)
+    scores_sum = torch.empty((batch, nheads), device="cuda", dtype=torch.float)
+    logsum = torch.empty((batch, nheads), device="cuda", dtype=torch.float)
+    gacc_o = torch.empty((num_split, batch, nheads, dim), device="cuda", dtype=torch.float)
+    glogsum = torch.empty((num_split, batch, nheads), device="cuda", dtype=torch.float)
+
+    Q_ = Q * scale
+    K_ = K.expand(-1, -1, nheads, -1)
+    V_ = V.expand(-1, -1, nheads, -1)
+
+    for ks in range(num_split):
+        acc_o.fill_(0)
+        logsum.fill_(0)
+        scores_max.fill_(float('-inf'))
+        scores_max_prev.fill_(float('-inf'))
+        for i in range(int((seqlen_kv // num_split) / block_N)):
+            acc_s.fill_(0)
+            acc_s = torch.einsum('bhd,bkhd->bhk', Q_,
+                                 K_[:, (seqlen_kv // num_split) * ks +
+                                    i * block_N:(seqlen_kv // num_split) * ks +
+                                    (i + 1) * block_N, :, :])  # [batch, nheads, block_N]
+            scores_max_prev = scores_max
+            scores_max = acc_s.max(dim=-1, keepdim=False).values  # [batch, nheads]
+            scores_scale = torch.exp2(scores_max_prev - scores_max)  # [batch, nheads]
+            acc_o *= scores_scale[:, :, None]
+            acc_s = torch.exp2(acc_s - scores_max[:, :, None])
+            acc_s_cast = acc_s.to(torch.float16)  # [batch, nheads, block_N]
+            acc_o += torch.einsum(
+                'bhk,bkhd->bhd', acc_s_cast,
+                V_[:, (seqlen_kv // num_split) * ks + i * block_N:(seqlen_kv // num_split) * ks +
+                   (i + 1) * block_N, :, :])
+            scores_sum = acc_s.sum(dim=-1, keepdim=False)
+            logsum = logsum * scores_scale + scores_sum
+        acc_o /= logsum[:, :, None]
+        logsum = torch.log2(logsum) + scores_max
+        gacc_o[ks, :, :, :] = acc_o
+        glogsum[ks, :, :] = logsum
+
+    return glogsum.to(torch.float16).permute(1, 2, 0), gacc_o.to(torch.float16).permute(1, 2, 0, 3)
+
+
+def reduce_ref(Q, K, V, glse, Output_partial):
+    o = torch.empty_like(Output_partial[:, :, 0, :]).fill_(0)
+    lse_logsum = torch.empty_like(glse[:, :, 0]).fill_(0)
+    lse_max = glse.max(dim=2, keepdim=False).values
+    for ks in range(num_split):
+        lse = glse[:, :, ks]
+        lse_logsum += torch.exp2(lse - lse_max)
+    lse_logsum = torch.log2(lse_logsum) + lse_max
+    for ks in range(num_split):
+        lse = glse[:, :, ks]
+        scale = torch.exp2(lse - lse_logsum)
+        o += Output_partial[:, :, ks, :] * scale[:, :, None]
+    return o.to(torch.float16)
+
+
+if __name__ == "__main__":
+    BATCH, H_Q, KV_H, KV_CTX, D_HEAD, DPE = 64, 128, 1, 8192, 512, 64
+    qk_flops = 2 * BATCH * H_Q * KV_CTX * (D_HEAD + DPE)
+    pv_flops = 2 * BATCH * H_Q * KV_CTX * D_HEAD
+    total_flops = qk_flops + pv_flops
+    BLOCK_N = 32  # if D_HEAD <= 128 else 32
+    BLOCK_H = 64
+
+    program = flashattn(BATCH, H_Q, KV_H, KV_CTX, D_HEAD, DPE, BLOCK_N, BLOCK_H)
+    mod, params = tilelang.lower(program)
+    mod = tilelang.Profiler(mod, params, [5], tilelang.TensorSupplyType.Normal)
+    mod.assert_allclose(ref_program, rtol=0.01, atol=0.01)
+    latency = mod.do_bench(mod.func, warmup=500)
+    print("Tile-lang: {:.2f} ms".format(latency))
+    print("Tile-lang: {:.2f} TFlops".format(total_flops / latency * 1e-9))

examples/gemm_splitk/example_tilelang_gemm_splitk.py

@@ -0,0 +1,70 @@
+# Copyright (c) Microsoft Corporation.
+# Licensed under the MIT License.
+
+import tilelang
+import tilelang.language as T
+from tvm import DataType
+
+
+def matmul(M, N, K, block_M, block_N, block_K, split_k, dtype="float16", accum_dtype="float"):
+
+    splitK = K // split_k
+
+    @T.prim_func
+    def main(
+            A: T.Buffer((M, K), dtype),
+            B: T.Buffer((N, K), dtype),
+            C: T.Buffer((M, N), dtype),
+    ):
+        with T.Kernel(
+                T.ceildiv(N, block_N), T.ceildiv(M, block_M), split_k, threads=128) as (bx, by, bz):
+            A_shared = T.alloc_shared((block_M, block_K), dtype, "shared")
+            B_shared = T.alloc_shared((block_K, block_N), dtype, "shared")
+            C_shared = T.alloc_shared((block_M, block_N), dtype, "shared")
+            C_local = T.alloc_fragment((block_M, block_N), accum_dtype)
+
+            if bz == 0:
+                # fuse the zero initialization kernel
+                for i, j in T.Parallel(block_M, block_N):
+                    m, n = by * block_M + i, bx * block_N + j
+                    C[m, n] = T.cast(0, dtype)
+
+            T.clear(C_local)
+            for ko in T.Pipelined(T.ceildiv(splitK, block_K), num_stages=0):
+                T.copy(A[by * block_M, bz * splitK + ko * block_K], A_shared)
+                T.copy(B[bz * splitK + ko * block_K, bx * block_N], B_shared)
+                T.gemm(A_shared, B_shared, C_local)
+
+            T.copy(C_local, C_shared)
+
+            if DataType(dtype).bits == 16:
+                for i, j in T.Parallel(block_M, block_N // 2):
+                    m, n = by * block_M + i, bx * block_N + j * 2
+                    # vectorized atomic
+                    T.atomic_addx2(C[m, n], C_shared[i, j * 2])
+                else:
+                    for i, j in T.Parallel(block_M, block_N):
+                        T.atomic_add(C[by * block_M + i, bx * block_N + j], C_shared[i, j])
+
+    return main
+
+
+program = matmul(1024, 1024, 1024, 128, 128, 32, 4)
+
+kernel = tilelang.compile(program)
+
+print(kernel.get_kernel_source())
+
+import torch
+
+a = torch.randn(1024, 1024).cuda().half()
+b = torch.randn(1024, 1024).cuda().half()
+c = torch.zeros(1024, 1024).cuda().half()
+kernel(a, b, c)
+
+ref_c = a @ b
+
+print(c)
+print(ref_c)
+
+torch.testing.assert_close(c, ref_c, rtol=1e-2, atol=1e-2)