Add support for Marlin 2:4 sparsity (#2102)

This change adds support for 2:4 sparsity when using Marlin
quantization. The 2:4 kernel is used when:

* The quantizer is `marlin`;
* the quantizer checkpoint format is `marlin_24`.

Fixes #2098.

server/marlin/marlin_kernels/__init__.pyi

@@ -19,6 +19,23 @@ def gptq_marlin_gemm(
     """
     ...
 
+def gptq_marlin_24_gemm(
+    a: torch.Tensor,
+    b_q_weight: torch.Tensor,
+    b_meta: torch.Tensor,
+    b_scales: torch.Tensor,
+    workspace: torch.Tensor,
+    num_bits: int,
+    size_m: int,
+    size_n: int,
+    size_k: int,
+) -> torch.Tensor:
+    """
+    Matrix multiplication using Marlin kernels. This is an extension of
+    `marlin_gemm` that supports 2:4 sparsity.
+    """
+    ...
+
 def gptq_marlin_repack(
     b_q_weight: torch.Tensor,
     perm: torch.Tensor,

server/marlin/marlin_kernels/ext.cpp

@@ -5,6 +5,7 @@
 PYBIND11_MODULE(TORCH_EXTENSION_NAME, m) {
   m.def("gptq_marlin_gemm", &gptq_marlin_gemm,
         "Marlin gemm with GPTQ compatibility");
+  m.def("gptq_marlin_24_gemm", &gptq_marlin_24_gemm, "Marlin sparse 2:4 gemm");
   m.def("gptq_marlin_repack", &gptq_marlin_repack,
         "Repack GPTQ parameters for Marlin");
   m.def("marlin_gemm", &marlin_gemm, "Marlin gemm");

server/marlin/marlin_kernels/ext.hh

@@ -12,6 +12,13 @@ torch::Tensor gptq_marlin_gemm(torch::Tensor &a, torch::Tensor &b_q_weight,
                                int64_t num_bits, int64_t size_m, int64_t size_n,
                                int64_t size_k, bool is_k_full);
 
+torch::Tensor gptq_marlin_24_gemm(torch::Tensor &a, torch::Tensor &b_q_weight,
+                                  torch::Tensor &b_meta,
+                                  torch::Tensor &b_scales,
+                                  torch::Tensor &workspace, int64_t num_bits,
+                                  int64_t size_m, int64_t size_n,
+                                  int64_t size_k);
+
 torch::Tensor gptq_marlin_repack(torch::Tensor &b_q_weight, torch::Tensor &perm,
                                  int64_t size_k, int64_t size_n,
                                  int64_t num_bits);

server/marlin/marlin_kernels/sparse/common/base.h

+/*
+ * Copyright (C) 2024 Roberto Lopez Castro (roberto.lopez.castro@udc.es). All
+ * Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+namespace marlin_24 {
+
+constexpr int ceildiv(int a, int b) { return (a + b - 1) / b; }
+
+// Instances of `Vec` are used to organize groups of >>registers<<, as needed
+// for instance as inputs to tensor core operations. Consequently, all
+// corresponding index accesses must be compile-time constants, which is why we
+// extensively use `#pragma unroll` throughout the kernel code to guarantee
+// this.
+template <typename T, int n>
+struct Vec {
+  T elems[n];
+  __device__ T& operator[](int i) { return elems[i]; }
+};
+
+template <int M_, int N_, int K_>
+struct ShapeBase {
+  static constexpr int M = M_, N = N_, K = K_;
+};
+
+using I4 = Vec<int, 4>;
+
+// Matrix fragments for tensor core instructions; their precise layout is
+// documented here:
+// https://docs.nvidia.com/cuda/parallel-thread-execution/index.html#matrix-fragments-for-mma-m16n8k16-with-floating-point-type
+using FragA = Vec<half2, 4>;
+using FragB = Vec<half2, 2>;
+using FragM = Vec<uint, 1>;
+using FragC = Vec<float, 4>;
+using FragS = Vec<half2, 1>;  // quantization scales
+
+}  // namespace marlin_24

server/marlin/marlin_kernels/sparse/common/mem.h

+/*
+ * Copyright (C) 2024 Roberto Lopez Castro (roberto.lopez.castro@udc.es). All
+ * Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+#include "base.h"
+
+namespace marlin_24 {
+// Predicated asynchronous global->shared copy; used for inputs A where we apply
+// predication to handle batchsizes that are not multiples of 16.
+__device__ inline void cp_async4_pred_zfill(void* smem_ptr,
+                                            const void* glob_ptr,
+                                            bool pred = true,
+                                            const bool zfill = false) {
+  const int BYTES = 16;
+  int src_in_bytes = (zfill ? 0 : BYTES);
+  uint32_t smem = static_cast<uint32_t>(__cvta_generic_to_shared(smem_ptr));
+  asm volatile(
+      "{\n"
+      "   .reg .pred p;\n"
+      "   setp.ne.b32 p, %0, 0;\n"
+      "   @p cp.async.cg.shared.global [%1], [%2], %3;\n"
+      "}\n" ::"r"((int)pred),
+      "r"(smem), "l"(glob_ptr), "n"(BYTES), "r"(src_in_bytes));
+}
+
+__device__ inline void cp_async4_pred(void* smem_ptr, const void* glob_ptr,
+                                      bool pred = true) {
+  const int BYTES = 16;
+  uint32_t smem = static_cast<uint32_t>(__cvta_generic_to_shared(smem_ptr));
+  asm volatile(
+      "{\n"
+      "   .reg .pred p;\n"
+      "   setp.ne.b32 p, %0, 0;\n"
+      "   @p cp.async.cg.shared.global [%1], [%2], %3;\n"
+      "}\n" ::"r"((int)pred),
+      "r"(smem), "l"(glob_ptr), "n"(BYTES));
+}
+
+// Asynchronous global->shared copy
+__device__ inline void cp_async4(void* smem_ptr, const void* glob_ptr) {
+  const int BYTES = 16;
+  uint32_t smem = static_cast<uint32_t>(__cvta_generic_to_shared(smem_ptr));
+  asm volatile(
+      "{\n"
+      "   cp.async.cg.shared.global [%0], [%1], %2;\n"
+      "}\n" ::"r"(smem),
+      "l"(glob_ptr), "n"(BYTES));
+}
+
+// Async copy fence.
+__device__ inline void cp_async_fence() {
+  asm volatile("cp.async.commit_group;\n" ::);
+}
+
+// Wait until at most `n` async copy stages are still pending.
+template <int n>
+__device__ inline void cp_async_wait() {
+  asm volatile("cp.async.wait_group %0;\n" ::"n"(n));
+}
+
+// Instruction for loading a full 16x16 matrix fragment of operand A from shared
+// memory, directly in tensor core layout.
+__device__ inline void ldsm4(FragA& frag_a, const void* smem_ptr) {
+  uint32_t* a = reinterpret_cast<uint32_t*>(&frag_a);
+  uint32_t smem = static_cast<uint32_t>(__cvta_generic_to_shared(smem_ptr));
+  asm volatile("ldmatrix.sync.aligned.m8n8.x4.shared.b16 {%0,%1,%2,%3}, [%4];\n"
+               : "=r"(a[0]), "=r"(a[1]), "=r"(a[2]), "=r"(a[3])
+               : "r"(smem));
+}
+
+__device__ inline void ldsm4_m(FragM& frag_m, const void* smem_ptr) {
+  uint32_t* a = reinterpret_cast<uint32_t*>(&frag_m);
+  uint32_t smem = static_cast<uint32_t>(__cvta_generic_to_shared(smem_ptr));
+  asm volatile("ldmatrix.sync.aligned.m8n8.x2.shared.b16 {%0,%1}, [%2];\n"
+               : "=r"(a[0]), "=r"(a[1])
+               : "r"(smem));
+}
+
+// Instruction for loading a full 16x16 matrix fragment of operand A from shared
+// memory, directly in tensor core layout.
+__device__ inline void ldsm4_t(FragA& frag_a, const void* smem_ptr) {
+  uint32_t* a = reinterpret_cast<uint32_t*>(&frag_a);
+  uint32_t smem = static_cast<uint32_t>(__cvta_generic_to_shared(smem_ptr));
+  asm volatile(
+      "ldmatrix.sync.aligned.m8n8.x4.trans.shared.b16 {%0,%1,%2,%3}, [%4];\n"
+      : "=r"(a[0]), "=r"(a[1]), "=r"(a[2]), "=r"(a[3])
+      : "r"(smem));
+}
+
+// Wait until barrier reaches `count`, then lock for current threadblock.
+__device__ inline void barrier_acquire(int* lock, int count) {
+  if (threadIdx.x == 0) {
+    int state = -1;
+    do
+      // Guarantee that subsequent writes by this threadblock will be visible
+      // globally.
+      asm volatile("ld.global.acquire.gpu.b32 %0, [%1];\n"
+                   : "=r"(state)
+                   : "l"(lock));
+    while (state != count);
+  }
+  __syncthreads();
+}
+
+// Release barrier and increment visitation count.
+__device__ inline void barrier_release(int* lock, bool reset = false) {
+  __syncthreads();
+  if (threadIdx.x == 0) {
+    if (reset) {
+      lock[0] = 0;
+      return;
+    }
+    int val = 1;
+    // Make sure that all writes since acquiring this barrier are visible
+    // globally, while releasing the barrier.
+    asm volatile("fence.acq_rel.gpu;\n");
+    asm volatile("red.relaxed.gpu.global.add.s32 [%0], %1;\n"
+                 :
+                 : "l"(lock), "r"(val));
+  }
+}
+}  // namespace marlin_24

server/marlin/marlin_kernels/sparse/common/mma.h

+/*
+ * Copyright (C) 2024 Roberto Lopez Castro (roberto.lopez.castro@udc.es). All
+ * Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+#include "base.h"
+#include <cudaTypedefs.h>
+
+namespace marlin_24 {
+
+// On CUDA earlier than 12.5, the ordered_metadata version of this instruction
+// is not supported. On later versions of CUDA the version without ordered
+// metadata results in the following warning:
+//  | Advisory: Modifier ‘.sp::ordered_metadata’ should be used on instruction
+//  | ‘mma’ instead of modifier ‘.sp’ as it is expected to have substantially
+//  | reduced performance on some future architectures
+#if defined CUDA_VERSION && CUDA_VERSION >= 12050
+  #define MMA_SP_INST \
+    "mma.sp::ordered_metadata.sync.aligned.m16n8k32.row.col.f32.f16.f16.f32 "
+#else
+  #define MMA_SP_INST "mma.sp.sync.aligned.m16n8k32.row.col.f32.f16.f16.f32 "
+#endif
+
+// m16n8k32 sparse tensor core mma instruction with fp16 inputs and fp32
+// output/accumulation.
+__device__ inline void mma_sp(const FragB& a_frag0, const FragB& a_frag1,
+                              const FragA& frag_b, FragC& frag_c, FragM& frag_m,
+                              const int psel) {
+  const uint32_t* a0 = reinterpret_cast<const uint32_t*>(&a_frag0);
+  const uint32_t* a1 = reinterpret_cast<const uint32_t*>(&a_frag1);
+  const uint32_t* b = reinterpret_cast<const uint32_t*>(&frag_b);
+  const uint32_t* e = reinterpret_cast<const uint32_t*>(&frag_m);
+
+  float* c = reinterpret_cast<float*>(&frag_c);
+  if (psel == 0) {
+    asm volatile(MMA_SP_INST
+                 "{%0, %1, %2, %3}, {%4, %5, %6, %7}, {%8, %9, %10,%11}, "
+                 "{%12,%13,%14,%15}, %16, 0x0;\n"
+                 : "=f"(c[0]), "=f"(c[1]), "=f"(c[2]), "=f"(c[3])
+                 : "r"(a0[0]), "r"(a1[0]), "r"(a0[1]), "r"(a1[1]), "r"(b[0]),
+                   "r"(b[2]), "r"(b[4]), "r"(b[6]), "f"(c[0]), "f"(c[1]),
+                   "f"(c[2]), "f"(c[3]), "r"(e[0]));
+    asm volatile(MMA_SP_INST
+                 "{%0, %1, %2, %3}, {%4, %5, %6, %7}, {%8, %9, %10,%11}, "
+                 "{%12,%13,%14,%15}, %16, 0x0;\n"
+                 : "=f"(c[4]), "=f"(c[5]), "=f"(c[6]), "=f"(c[7])
+                 : "r"(a0[0]), "r"(a1[0]), "r"(a0[1]), "r"(a1[1]), "r"(b[1]),
+                   "r"(b[3]), "r"(b[5]), "r"(b[7]), "f"(c[4]), "f"(c[5]),
+                   "f"(c[6]), "f"(c[7]), "r"(e[0]));
+  } else {
+    asm volatile(MMA_SP_INST
+                 "{%0, %1, %2, %3}, {%4, %5, %6, %7}, {%8, %9, %10,%11}, "
+                 "{%12,%13,%14,%15}, %16, 0x1;\n"
+                 : "=f"(c[0]), "=f"(c[1]), "=f"(c[2]), "=f"(c[3])
+                 : "r"(a0[0]), "r"(a1[0]), "r"(a0[1]), "r"(a1[1]), "r"(b[0]),
+                   "r"(b[2]), "r"(b[4]), "r"(b[6]), "f"(c[0]), "f"(c[1]),
+                   "f"(c[2]), "f"(c[3]), "r"(e[0]));
+    asm volatile(MMA_SP_INST
+                 "{%0, %1, %2, %3}, {%4, %5, %6, %7}, {%8, %9, %10,%11}, "
+                 "{%12,%13,%14,%15}, %16, 0x1;\n"
+                 : "=f"(c[4]), "=f"(c[5]), "=f"(c[6]), "=f"(c[7])
+                 : "r"(a0[0]), "r"(a1[0]), "r"(a0[1]), "r"(a1[1]), "r"(b[1]),
+                   "r"(b[3]), "r"(b[5]), "r"(b[7]), "f"(c[4]), "f"(c[5]),
+                   "f"(c[6]), "f"(c[7]), "r"(e[0]));
+  }
+}
+
+// Lookup-table based 3-input logical operation; explicitly used for
+// dequantization as the compiler does not seem to automatically recognize it in
+// all cases.
+template <int lut>
+__device__ inline int lop3(int a, int b, int c) {
+  int res;
+  asm volatile("lop3.b32 %0, %1, %2, %3, %4;\n"
+               : "=r"(res)
+               : "r"(a), "r"(b), "r"(c), "n"(lut));
+  return res;
+}
+
+__device__ __forceinline__ uint2 to_half4(float c0, float c1, float c2,
+                                          float c3) {
+  uint2 r;
+  asm("{\n\t"
+      ".reg .f16 a, b, c, d; \n\t"
+      "cvt.rn.f16.f32 a, %2; \n\t"
+      "cvt.rn.f16.f32 b, %3; \n\t"
+      "cvt.rn.f16.f32 c, %4; \n\t"
+      "cvt.rn.f16.f32 d, %5; \n\t"
+      "mov.b32 %0, {a, b};   \n\t"
+      "mov.b32 %1, {c, d};   \n\t"
+      "}"
+      : "=r"(r.x), "=r"(r.y)
+      : "f"(c0), "f"(c1), "f"(c2), "f"(c3));
+  return r;
+}
+
+// Constructs destination register by taking bytes from 2 sources (based on
+// mask)
+template <int start_byte, int mask>
+__device__ inline uint32_t prmt(uint32_t a) {
+  uint32_t res;
+  asm volatile("prmt.b32 %0, %1, %2, %3;\n"
+               : "=r"(res)
+               : "r"(a), "n"(start_byte), "n"(mask));
+  return res;
+}
+
+// Efficiently dequantize an int32 value into a full B-fragment of 4 fp16
+// values. We mostly follow the strategy in the link below, with some small
+// changes:
+// https://github.com/NVIDIA/FasterTransformer/blob/main/src/fastertransformer/cutlass_extensions/include/cutlass_extensions/interleaved_numeric_conversion.h
+__device__ inline FragB dequant_4bit(int q) {
+  const int LO = 0x000f000f;
+  const int HI = 0x00f000f0;
+  const int EX = 0x64006400;
+  // Guarantee that the `(a & b) | c` operations are LOP3s.
+  int lo = lop3<(0xf0 & 0xcc) | 0xaa>(q, LO, EX);
+  int hi = lop3<(0xf0 & 0xcc) | 0xaa>(q, HI, EX);
+  // We want signed int4 outputs, hence we fuse the `-8` symmetric zero point
+  // directly into `SUB` and `ADD`.
+  const int SUB = 0x64086408;
+  const int MUL = 0x2c002c00;
+  const int ADD = 0xd480d480;
+
+  FragB frag_b;
+  frag_b[0] = __hsub2(*reinterpret_cast<half2*>(&lo),
+                      *reinterpret_cast<const half2*>(&SUB));
+  frag_b[1] = __hfma2(*reinterpret_cast<half2*>(&hi),
+                      *reinterpret_cast<const half2*>(&MUL),
+                      *reinterpret_cast<const half2*>(&ADD));
+  return frag_b;
+}
+
+// Efficiently dequantize an int32 value into a full B-fragment of 4 fp16
+// values. We mostly follow the strategy in the link below, with some small
+// changes:
+// https://github.com/NVIDIA/FasterTransformer/blob/main/src/fastertransformer/cutlass_extensions/include/cutlass_extensions/interleaved_numeric_conversion.h
+__device__ inline FragB dequant_8bit(int q) {
+  static constexpr uint32_t mask_for_elt_01 = 0x5250;
+  static constexpr uint32_t mask_for_elt_23 = 0x5351;
+  static constexpr uint32_t start_byte_for_fp16 = 0x64646464;
+
+  uint32_t lo = prmt<start_byte_for_fp16, mask_for_elt_01>(q);
+  uint32_t hi = prmt<start_byte_for_fp16, mask_for_elt_23>(q);
+
+  static constexpr uint32_t I8s_TO_F16s_MAGIC_NUM = 0x64806480;
+
+  FragB frag_b;
+  frag_b[0] = __hsub2(*reinterpret_cast<half2*>(&lo),
+                      *reinterpret_cast<const half2*>(&I8s_TO_F16s_MAGIC_NUM));
+  frag_b[1] = __hsub2(*reinterpret_cast<half2*>(&hi),
+                      *reinterpret_cast<const half2*>(&I8s_TO_F16s_MAGIC_NUM));
+  return frag_b;
+}
+
+// Multiply dequantized values by the corresponding quantization scale; used
+// only for grouped quantization.
+__device__ inline void scale(FragB& frag_b, FragS& frag_s, int i) {
+  half2 s = __half2half2(reinterpret_cast<__half*>(&frag_s)[i]);
+  frag_b[0] = __hmul2(frag_b[0], s);
+  frag_b[1] = __hmul2(frag_b[1], s);
+}
+
+__device__ inline void scale_floats(float* c0, float* c1, float* c2, float* c3,
+                                    FragS& s0, float* c4, float* c5, float* c6,
+                                    float* c7, FragS& s1) {
+  *c0 = __fmul_rn(*c0, __half2float(s0[0].x));
+  *c1 = __fmul_rn(*c1, __half2float(s0[0].y));
+  *c2 = __fmul_rn(*c2, __half2float(s0[1].x));
+  *c3 = __fmul_rn(*c3, __half2float(s0[1].y));
+
+  *c4 = __fmul_rn(*c4, __half2float(s1[0].x));
+  *c5 = __fmul_rn(*c5, __half2float(s1[0].y));
+  *c6 = __fmul_rn(*c6, __half2float(s1[1].x));
+  *c7 = __fmul_rn(*c7, __half2float(s1[1].y));
+}
+
+}  // namespace marlin_24

server/marlin/setup.py

@@ -12,6 +12,7 @@ setup(
                 "marlin_kernels/gptq_marlin.cu",
                 "marlin_kernels/gptq_marlin_repack.cu",
                 "marlin_kernels/marlin_cuda_kernel.cu",
+                "marlin_kernels/sparse/marlin_24_cuda_kernel.cu",
                 "marlin_kernels/ext.cpp",
             ],
             extra_compile_args=extra_compile_args,

server/text_generation_server/layers/linear.py

 from typing import Optional
 import torch
 from torch.nn import functional as F
-from text_generation_server.layers.marlin import GPTQMarlinLinear
 from text_generation_server.utils.import_utils import SYSTEM
 
 if SYSTEM == "rocm":
@@ -225,6 +224,9 @@ def get_linear(weight, bias, quantize):
             )
     elif quantize == "marlin":
         from text_generation_server.layers.marlin import (
+            GPTQMarlin24Linear,
+            GPTQMarlin24Weight,
+            GPTQMarlinLinear,
             GPTQMarlinWeight,
             MarlinLinear,
             MarlinWeight,
@@ -235,6 +237,11 @@ def get_linear(weight, bias, quantize):
                 weight=weight,
                 bias=bias,
             )
+        elif isinstance(weight, GPTQMarlin24Weight):
+            linear = GPTQMarlin24Linear(
+                weight=weight,
+                bias=bias,
+            )
         elif isinstance(weight, MarlinWeight):
             linear = MarlinLinear(weight=weight, bias=bias)
         else:

server/text_generation_server/layers/marlin.py

 from dataclasses import dataclass
-from typing import Optional, Tuple, List
+from typing import List, Optional, Tuple
 
 import torch
 import torch.nn as nn
-
 from text_generation_server.utils.import_utils import SYSTEM
 
 try:
@@ -177,12 +176,12 @@ class GPTQMarlinLinear(nn.Module):
         self.bits = weight.bits
         self.is_full_k = weight.is_full_k
 
-        self.register_buffer("qweight", weight.qweight)
-        self.register_buffer("scales", weight.scales)
-        self.register_buffer("g_idx", weight.g_idx)
-        self.register_buffer("perm", weight.perm)
+        self.qweight = weight.qweight
+        self.scales = weight.scales
+        self.g_idx = weight.g_idx
+        self.perm = weight.perm
         if bias is not None:
-            self.register_buffer("bias", bias)
+            self.bias = bias
         else:
             self.bias = None
 
@@ -215,6 +214,116 @@ class GPTQMarlinLinear(nn.Module):
         return C
 
 
+GPTQ_MARLIN_24_MIN_THREAD_N = 128
+GPTQ_MARLIN_24_MIN_THREAD_K = 128
+GPTQ_MARLIN_24_MAX_PARALLEL = 64
+GPTQ_MARLIN_24_SUPPORTED_NUM_BITS = [4, 8]
+GPTQ_MARLIN_24_SUPPORTED_GROUP_SIZES = [-1, 128]
+
+
+@dataclass
+class GPTQMarlin24Weight:
+    """
+    GPTQ-Marlin 2:4 weights.
+
+    Attributes:
+        B (torch.Tensor): int4-quantized weights packed into int32.
+        B_meta (torch.Tensor): metadata for 2:4 sparsity.
+        s (torch.Tensor): float16 scales.
+        bits: quantized weight size.
+    """
+
+    B: torch.Tensor
+    B_meta: torch.Tensor
+    s: torch.Tensor
+    bits: int
+
+    def __post_init__(self):
+        assert self.B.dtype == torch.int32
+        assert self.B_meta.dtype == torch.int16
+        assert self.s.dtype == torch.float16
+
+
+class GPTQMarlin24Linear(nn.Module):
+    def __init__(self, *, weight: GPTQMarlin24Weight, bias: Optional[torch.Tensor]):
+        super().__init__()
+
+        _check_marlin_kernels()
+        assert marlin_kernels is not None
+
+        if weight.bits not in GPTQ_MARLIN_BITS:
+            supported_bits = ", ".join(str(b) for b in GPTQ_MARLIN_BITS)
+            raise RuntimeError(
+                f"{weight.bits}-bit GPTQ Sparse 2:4 Marlin is not supported, must be one of: {supported_bits}"
+            )
+
+        in_features = weight.B.shape[0] * MARLIN_TILE_SIZE * 2
+        out_features = weight.s.shape[1]
+        groupsize = -1 if weight.s.shape[0] == 1 else in_features // weight.s.shape[0]
+
+        if groupsize not in GPTQ_MARLIN_24_SUPPORTED_GROUP_SIZES:
+            supported_sizes = ", ".join(
+                str(b) for b in GPTQ_MARLIN_24_SUPPORTED_GROUP_SIZES
+            )
+            raise RuntimeError(
+                f"Group size {groupsize} is not supported, must be one of: {supported_sizes}"
+            )
+
+        self.bits = weight.bits
+        weights_per_int32 = 32 // self.bits
+
+        assert (
+            out_features % GPTQ_MARLIN_24_MIN_THREAD_N == 0
+        ), f"Number of output features ({out_features}) not divisable by {GPTQ_MARLIN_24_MIN_THREAD_N} threads"
+        assert (
+            out_features % weights_per_int32 == 0
+        ), f"Number of output features ({out_features}) not divisable by weights per int32 ({weights_per_int32})"
+
+        assert (
+            in_features % GPTQ_MARLIN_24_MIN_THREAD_K == 0
+        ), f"Number of output features ({out_features}) not divisable by {GPTQ_MARLIN_24_MIN_THREAD_K} threads"
+        if groupsize != -1 and in_features % groupsize != 0:
+            raise ValueError(
+                f"Number of input features ({in_features}) not divisable by group size ({groupsize})"
+            )
+
+        self.B = weight.B
+        self.B_meta = weight.B_meta
+        self.s = weight.s
+        if bias is not None:
+            self.bias = bias
+        else:
+            self.bias = None
+
+        self.workspace = torch.zeros(
+            (out_features // GPTQ_MARLIN_24_MIN_THREAD_N) * GPTQ_MARLIN_24_MAX_PARALLEL,
+            dtype=torch.int,
+            device=weight.B.device,
+        )
+
+    def forward(self, A: torch.Tensor) -> torch.Tensor:
+        assert marlin_kernels is not None
+
+        C = marlin_kernels.gptq_marlin_24_gemm(
+            A.view(-1, A.shape[-1]),
+            self.B,
+            self.B_meta,
+            self.s,
+            self.workspace,
+            self.bits,
+            A.shape[0],
+            self.s.shape[1],
+            A.shape[1],
+        )
+
+        C = C.reshape(A.shape[:-1] + (self.s.shape[1],))
+
+        if self.bias is not None:
+            C += self.bias
+
+        return C
+
+
 @dataclass
 class MarlinWeight:
     """
@@ -255,10 +364,10 @@ class MarlinLinear(nn.Module):
             128,
         }, f"Group size must be -1 or 128, was {groupsize}"
 
-        self.register_buffer("B", weight.B)
-        self.register_buffer("s", weight.s)
+        self.B = weight.B
+        self.s = weight.s
         if bias is not None:
-            self.register_buffer("bias", bias)
+            self.bias = bias
         else:
             self.bias = None
 

server/text_generation_server/utils/weights.py

@@ -13,6 +13,7 @@ from text_generation_server.utils.log import log_once
 @dataclass
 class _GPTQParams:
     bits: int
+    checkpoint_format: Optional[str]
     groupsize: int
     desc_act: bool
     quant_method: str
@@ -263,12 +264,29 @@ class Weights:
             )
         elif quantize == "marlin":
             from text_generation_server.layers.marlin import (
+                GPTQMarlin24Weight,
                 MarlinWeight,
                 repack_gptq_for_marlin,
             )
 
             quant_method = getattr(self, "quant_method", "marlin")
-            if quant_method == "gptq":
+            is_marlin_24 = getattr(self, "gptq_checkpoint_format", None) == "marlin_24"
+            if is_marlin_24:
+                B = self.get_packed_sharded(
+                    f"{prefix}.B_24", dim=1, block_sizes=block_sizes
+                )
+                B_meta = self.get_packed_sharded(
+                    f"{prefix}.B_meta", dim=1, block_sizes=block_sizes
+                )
+                s = self.get_packed_sharded(
+                    f"{prefix}.s", dim=1, block_sizes=block_sizes
+                )
+
+                gptq_params = self._get_gptq_params()
+                weight = GPTQMarlin24Weight(
+                    B=B, B_meta=B_meta, s=s, bits=gptq_params.bits
+                )
+            elif quant_method == "gptq":
                 gptq_params = self._get_gptq_params()
                 try:
                     qweight = self.get_packed_sharded(
@@ -293,7 +311,6 @@ class Weights:
                     sym=gptq_params.sym,
                     sharded_infeatures=False,
                 )
-
             else:
                 B = self.get_packed_sharded(
                     f"{prefix}.B", dim=1, block_sizes=block_sizes
@@ -406,12 +423,36 @@ class Weights:
         elif quantize == "marlin":
             from text_generation_server.layers.gptq import GPTQWeight
             from text_generation_server.layers.marlin import (
+                GPTQMarlin24Weight,
                 MarlinWeight,
                 repack_gptq_for_marlin,
             )
 
             quant_method = getattr(self, "quant_method", "marlin")
-            if quant_method == "gptq":
+            is_marlin_24 = getattr(self, "gptq_checkpoint_format", None) == "marlin_24"
+            if is_marlin_24:
+                try:
+                    B = torch.cat(
+                        [self.get_sharded(f"{p}.B_24", dim=1) for p in prefixes], dim=1
+                    )
+                except RuntimeError:
+                    raise RuntimeError(
+                        f"Cannot load `{quantize}` weight, make sure the model is already quantized"
+                    )
+
+                B_meta = torch.cat(
+                    [self.get_sharded(f"{p}.B_meta", dim=1) for p in prefixes], dim=1
+                )
+
+                s = torch.cat(
+                    [self.get_sharded(f"{p}.s", dim=1) for p in prefixes], dim=1
+                )
+
+                gptq_params = self._get_gptq_params()
+                weight = GPTQMarlin24Weight(
+                    B=B, B_meta=B_meta, s=s, bits=gptq_params.bits
+                )
+            elif quant_method == "gptq":
                 gptq_params = self._get_gptq_params()
                 try:
                     qweight = torch.cat(
@@ -629,12 +670,35 @@ class Weights:
         elif quantize == "marlin":
             from text_generation_server.layers.gptq import GPTQWeight
             from text_generation_server.layers.marlin import (
+                GPTQMarlin24Weight,
                 MarlinWeight,
                 repack_gptq_for_marlin,
             )
 
             quant_method = getattr(self, "quant_method", "marlin")
-            if quant_method == "gptq":
+            is_marlin_24 = getattr(self, "gptq_checkpoint_format", None) == "marlin_24"
+            if is_marlin_24:
+                try:
+                    B = self.get_sharded(f"{prefix}.B_24", dim=0)
+                except RuntimeError:
+                    raise RuntimeError(
+                        "Cannot load `marlin` 2:4 sparsity weight, make sure the model is already quantized."
+                    )
+
+                B_meta = self.get_sharded(f"{prefix}.B_meta", dim=0)
+                num_groups = self._get_slice(f"{prefix}.s").get_shape()[0]
+                if num_groups == 1:
+                    # The number of groups is 1 when groupsize == -1. share
+                    # scales between all shards in this case.
+                    s = self.get_tensor(f"{prefix}.s")
+                else:
+                    s = self.get_sharded(f"{prefix}.s", dim=0)
+
+                gptq_params = self._get_gptq_params()
+                weight = GPTQMarlin24Weight(
+                    B=B, B_meta=B_meta, s=s, bits=gptq_params.bits
+                )
+            elif quant_method == "gptq":
                 log_once(logger.info, "Converting GPTQ model to Marlin packing format.")
                 gptq_params = self._get_gptq_params()
 
@@ -668,7 +732,7 @@ class Weights:
                     B = self.get_sharded(f"{prefix}.B", dim=0)
                 except RuntimeError:
                     raise RuntimeError(
-                        "Cannot load `marlin` weight, make sure the model is already quantized, or quantize it with `text-generation-server quantize ORIGINAL_MODEL_ID NEW_MODEL_ID`"
+                        "Cannot load `marlin` weight, make sure the model is already quantized."
                     )
 
                 num_groups = self._get_slice(f"{prefix}.s").get_shape()[0]
@@ -688,6 +752,7 @@ class Weights:
         try:
             bits = self.get_tensor("gptq_bits").item()
             groupsize = self.get_tensor("gptq_groupsize").item()
+            checkpoint_format = getattr(self, "gptq_checkpoint_format", None)
             desc_act = False
             sym = True
             quant_method = "gptq"
@@ -695,6 +760,7 @@ class Weights:
             try:
                 bits = self.gptq_bits
                 groupsize = self.gptq_groupsize
+                checkpoint_format = getattr(self, "gptq_checkpoint_format", None)
                 desc_act = getattr(self, "gptq_desc_act", False)
                 quant_method = getattr(self, "quant_method", "gptq")
                 sym = getattr(self, "sym", True)
@@ -703,6 +769,7 @@ class Weights:
 
         return _GPTQParams(
             bits=bits,
+            checkpoint_format=checkpoint_format,
             desc_act=desc_act,
             groupsize=groupsize,
             quant_method=quant_method,
@@ -724,6 +791,9 @@ class Weights:
             self.gptq_groupsize = data["quantization_config"]["group_size"]
             # Order is important here, desc_act is missing on some real models
             self.quant_method = data["quantization_config"]["quant_method"]
+            self.gptq_checkpoint_format = data["quantization_config"].get(
+                "checkpoint_format"
+            )
             self.gptq_sym = data["quantization_config"]["sym"]
             self.gptq_desc_act = data["quantization_config"]["desc_act"]
         except Exception: