vulkan: implement SSM scan operation

Add State Space Model scan operation to the Vulkan backend.

Signed-off-by: Giuseppe Scrivano <[email protected]>

Author: giuseppe

ggml/src/ggml-vulkan/ggml-vulkan.cpp

@@ -582,6 +582,8 @@ struct vk_device_struct {
     vk_pipeline pipeline_pool2d_f32;
     vk_pipeline pipeline_rwkv_wkv6_f32;
     vk_pipeline pipeline_rwkv_wkv7_f32;
+    vk_pipeline pipeline_ssm_scan_f32_d128;
+    vk_pipeline pipeline_ssm_scan_f32_d256;
     vk_pipeline pipeline_opt_step_adamw_f32;
     vk_pipeline pipeline_opt_step_sgd_f32;
     vk_pipeline pipeline_conv2d_f32[CONV_SHAPE_COUNT];
@@ -1087,6 +1089,13 @@ struct vk_op_rwkv_wkv7_push_constants {
     uint32_t C;
     uint32_t H;
 };
+struct vk_op_ssm_scan_push_constants {
+    uint32_t nb02, nb03, nb12, nb13;
+    uint32_t nb21, nb22, nb31;
+    uint32_t nb42, nb43, nb52, nb53;
+    uint32_t s_off;
+    uint32_t n_head, d_head, n_group, n_tok;
+};
 
 struct vk_op_conv2d_push_constants {
     uint32_t Cout;
@@ -3591,6 +3600,9 @@ static void ggml_vk_load_shaders(vk_device& device) {
 
     ggml_vk_create_pipeline(device, device->pipeline_rwkv_wkv7_f32, "rwkv_wkv7_f32", rwkv_wkv7_f32_len, rwkv_wkv7_f32_data, "main", 8, sizeof(vk_op_rwkv_wkv7_push_constants), {1, 1, 1}, {device->subgroup_size}, 1);
 
+    ggml_vk_create_pipeline(device, device->pipeline_ssm_scan_f32_d128, "ssm_scan_f32", ssm_scan_f32_len, ssm_scan_f32_data, "main", 8, sizeof(vk_op_ssm_scan_push_constants), {1, 1, 1}, {128, device->subgroup_size, 16}, 1);
+    ggml_vk_create_pipeline(device, device->pipeline_ssm_scan_f32_d256, "ssm_scan_f32", ssm_scan_f32_len, ssm_scan_f32_data, "main", 8, sizeof(vk_op_ssm_scan_push_constants), {1, 1, 1}, {256, device->subgroup_size, 16}, 1);
+
     ggml_vk_create_pipeline(device, device->pipeline_opt_step_adamw_f32, "opt_step_adamw_f32", opt_step_adamw_f32_len, opt_step_adamw_f32_data, "main", 5, sizeof(vk_op_push_constants), {512, 1, 1}, {}, 1);
 
     ggml_vk_create_pipeline(device, device->pipeline_opt_step_sgd_f32, "opt_step_sgd_f32", opt_step_sgd_f32_len, opt_step_sgd_f32_data, "main", 3, sizeof(vk_op_push_constants), {512, 1, 1}, {}, 1);
@@ -8098,6 +8110,16 @@ static vk_pipeline ggml_vk_op_get_pipeline(ggml_backend_vk_context * ctx, const
             return ctx->device->pipeline_rwkv_wkv7_f32;
         }
         return nullptr;
+    case GGML_OP_SSM_SCAN:
+        if (src0->type == GGML_TYPE_F32 && dst->type == GGML_TYPE_F32) {
+            const uint32_t d_state = src0->ne[0];
+            if (d_state == 128) {
+                return ctx->device->pipeline_ssm_scan_f32_d128;
+            } else if (d_state == 256) {
+                return ctx->device->pipeline_ssm_scan_f32_d256;
+            }
+        }
+        return nullptr;
     case GGML_OP_OPT_STEP_ADAMW:
         if (src0->type == GGML_TYPE_F32 && dst->type == GGML_TYPE_F32) {
             return ctx->device->pipeline_opt_step_adamw_f32;
@@ -9038,6 +9060,101 @@ static void ggml_vk_rwkv_wkv7(ggml_backend_vk_context * ctx, vk_context& subctx,
     );
 }
 
+static void ggml_vk_ssm_scan(ggml_backend_vk_context * ctx, vk_context& subctx, ggml_tensor * dst, bool dryrun = false) {
+    const ggml_tensor * src0 = dst->src[0];
+    const ggml_tensor * src1 = dst->src[1];
+    const ggml_tensor * src2 = dst->src[2];
+    const ggml_tensor * src3 = dst->src[3];
+    const ggml_tensor * src4 = dst->src[4];
+    const ggml_tensor * src5 = dst->src[5];
+
+    GGML_ASSERT(dst->buffer != nullptr);
+
+    const uint32_t head_dim = src0->ne[1];
+    const uint32_t n_head = src1->ne[1];
+    const uint32_t n_group = src4->ne[1];
+    const uint32_t n_tok = src1->ne[2];
+    const uint32_t n_seq = src1->ne[3];
+
+    bool is_mamba2 = (src3->nb[1] == sizeof(float));
+    GGML_ASSERT(is_mamba2);
+
+    vk_pipeline pipeline = ggml_vk_op_get_pipeline(ctx, src0, src1, src2, dst, dst->op);
+    GGML_ASSERT(pipeline != nullptr);
+
+    if (dryrun) {
+        ggml_pipeline_request_descriptor_sets(ctx, pipeline, 1);
+        return;
+    }
+
+    const int64_t s_off = ggml_nelements(src1) * sizeof(float);
+
+    const vk_op_ssm_scan_push_constants pc = {
+        (uint32_t)src0->nb[2], (uint32_t)src0->nb[3],
+        (uint32_t)src1->nb[2], (uint32_t)src1->nb[3],
+        (uint32_t)src2->nb[1], (uint32_t)src2->nb[2],
+        (uint32_t)src3->nb[1],
+        (uint32_t)src4->nb[2], (uint32_t)src4->nb[3],
+        (uint32_t)src5->nb[2], (uint32_t)src5->nb[3],
+        (uint32_t)s_off,
+        n_head, head_dim, n_group, n_tok
+    };
+
+    ggml_backend_vk_buffer_context * dst_buf_ctx = (ggml_backend_vk_buffer_context *)dst->buffer->context;
+    ggml_backend_vk_buffer_context * src_buf_ctxs[GGML_MAX_SRC];
+    for (int i = 0; i < GGML_MAX_SRC && dst->src[i] != nullptr; i++) {
+        src_buf_ctxs[i] = (ggml_backend_vk_buffer_context *)dst->src[i]->buffer->context;
+    }
+
+    vk_buffer d_D = nullptr, d_srcs[GGML_MAX_SRC] = { nullptr };
+    size_t dst_offset = 0, src_offsets[GGML_MAX_SRC] = { 0 };
+    bool dst_uma = false, srcs_uma[GGML_MAX_SRC] = { false };
+
+    if (ctx->device->uma) {
+        for (int i = 0; i < GGML_MAX_SRC && dst->src[i] != nullptr; i++) {
+            ggml_vk_host_get(ctx->device, dst->src[i]->data, d_srcs[i], src_offsets[i]);
+            srcs_uma[i] = d_srcs[i] != nullptr;
+        }
+        ggml_vk_host_get(ctx->device, dst->data, d_D, dst_offset);
+        dst_uma = d_D != nullptr;
+    }
+
+    if (!dst_uma) {
+        d_D = dst_buf_ctx->dev_buffer;
+        dst_offset = vk_tensor_offset(dst) + dst->view_offs;
+    }
+    for (int i = 0; i < GGML_MAX_SRC && dst->src[i] != nullptr; i++) {
+        if (!srcs_uma[i]) {
+            d_srcs[i] = src_buf_ctxs[i]->dev_buffer;
+            src_offsets[i] = vk_tensor_offset(dst->src[i]) + dst->src[i]->view_offs;
+        }
+    }
+
+    size_t dst_size = ggml_nbytes(dst);
+    size_t src_sizes[GGML_MAX_SRC];
+    for (int i = 0; i < GGML_MAX_SRC && dst->src[i] != nullptr; i++) {
+        src_sizes[i] = ggml_nbytes(dst->src[i]);
+    }
+
+    std::array<uint32_t, 3> elements;
+
+    const int splitH = 16;
+    const uint32_t num_workgroups_x = CEIL_DIV(n_head * head_dim, splitH);
+    const uint32_t num_workgroups_y = n_seq;
+    elements = { num_workgroups_x, num_workgroups_y, 1 };
+
+    ggml_vk_dispatch_pipeline(ctx, subctx, pipeline, {
+        vk_subbuffer{ d_srcs[0], src_offsets[0], src_sizes[0] },
+        vk_subbuffer{ d_srcs[1], src_offsets[1], src_sizes[1] },
+        vk_subbuffer{ d_srcs[2], src_offsets[2], src_sizes[2] },
+        vk_subbuffer{ d_srcs[3], src_offsets[3], src_sizes[3] },
+        vk_subbuffer{ d_srcs[4], src_offsets[4], src_sizes[4] },
+        vk_subbuffer{ d_srcs[5], src_offsets[5], src_sizes[5] },
+        vk_subbuffer{ d_srcs[6], src_offsets[6], src_sizes[6] },
+        vk_subbuffer{ d_D, dst_offset, dst_size }
+    }, pc, elements);
+}
+
 static void ggml_vk_op_f32_opt_step_adamw(ggml_backend_vk_context * ctx, vk_context& subctx, ggml_tensor * dst, const vk_op_push_constants&& pc, bool dryrun = false) {
     const ggml_tensor * x = dst->src[0];
     const ggml_tensor * g = dst->src[1];
@@ -10870,6 +10987,7 @@ static bool ggml_vk_build_graph(ggml_backend_vk_context * ctx, ggml_cgraph * cgr
     case GGML_OP_CONV_2D_DW:
     case GGML_OP_RWKV_WKV6:
     case GGML_OP_RWKV_WKV7:
+    case GGML_OP_SSM_SCAN:
     case GGML_OP_LEAKY_RELU:
     case GGML_OP_FLASH_ATTN_EXT:
     case GGML_OP_OPT_STEP_ADAMW:
@@ -11287,6 +11405,11 @@ static bool ggml_vk_build_graph(ggml_backend_vk_context * ctx, ggml_cgraph * cgr
 
         break;
 
+    case GGML_OP_SSM_SCAN:
+        ggml_vk_ssm_scan(ctx, compute_ctx, node, dryrun);
+
+        break;
+
     case GGML_OP_OPT_STEP_ADAMW:
         ggml_vk_opt_step_adamw(ctx, compute_ctx, node, dryrun);
 
@@ -11398,6 +11521,7 @@ static bool ggml_vk_compute_forward(ggml_backend_vk_context * ctx, ggml_cgraph *
     case GGML_OP_CONV_2D_DW:
     case GGML_OP_RWKV_WKV6:
     case GGML_OP_RWKV_WKV7:
+    case GGML_OP_SSM_SCAN:
     case GGML_OP_LEAKY_RELU:
     case GGML_OP_REPEAT:
     case GGML_OP_REPEAT_BACK:
@@ -12879,6 +13003,48 @@ static bool ggml_backend_vk_device_supports_op(ggml_backend_dev_t dev, const ggm
         case GGML_OP_RWKV_WKV6:
         case GGML_OP_RWKV_WKV7:
             return true;
+        case GGML_OP_SSM_SCAN:
+            {
+                for (int i = 0; i < 6; i++) {
+                    if (op->src[i] && ggml_is_quantized(op->src[i]->type)) {
+                        return false;
+                    }
+                }
+                if (op->src[6] && op->src[6]->type != GGML_TYPE_I32) {
+                    return false;
+                }
+                if (op->src[0]->type != GGML_TYPE_F32 || op->type != GGML_TYPE_F32) {
+                    return false;
+                }
+
+                const uint32_t d_state = op->src[0]->ne[0];
+                const uint32_t head_dim = op->src[0]->ne[1];
+
+                bool is_mamba2 = (op->src[3] && op->src[3]->nb[1] == sizeof(float));
+                if (!is_mamba2) {
+                    return false;
+                }
+
+                if ((d_state != 128 && d_state != 256) || head_dim % 16 != 0) {
+                    return false;
+                }
+
+                ggml_backend_vk_device_context * ctx = (ggml_backend_vk_device_context *)dev->context;
+                const vk_device& device = ggml_vk_get_device(ctx->device);
+
+                const uint32_t SPLIT_H = 16;
+                const uint32_t MAX_D_STATE = 256;
+
+                size_t stateC_size = SPLIT_H * MAX_D_STATE * sizeof(float);
+                size_t warp_sdata_size = MAX_D_STATE * sizeof(float);
+                size_t total_shared_memory = stateC_size + warp_sdata_size;
+
+                if (total_shared_memory > device->properties.limits.maxComputeSharedMemorySize) {
+                    return false;
+                }
+
+                return true;
+            }
         case GGML_OP_CONV_TRANSPOSE_1D:
             return op->src[0]->type == GGML_TYPE_F32 && op->src[1]->type == GGML_TYPE_F32;
         case GGML_OP_CONV_2D:
@@ -13223,14 +13389,14 @@ static void ggml_vk_check_results_0(ggml_backend_vk_context * ctx, ggml_cgraph *
 
     struct ggml_context * ggml_ctx = ggml_init(iparams);
 
-    std::array<struct ggml_tensor *, 6> src_clone = {nullptr, nullptr, nullptr, nullptr, nullptr, nullptr};
-    std::array<size_t, 6> src_size = {0, 0, 0, 0, 0, 0};
-    std::array<void *, 6> src_buffer = {nullptr, nullptr, nullptr, nullptr, nullptr, nullptr};
-    const char * srci_name[6] = {"src0", "src1", "src2", "src3", "src4", "src5"};
+    std::array<struct ggml_tensor *, GGML_MAX_SRC> src_clone = {nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr};
+    std::array<size_t, GGML_MAX_SRC> src_size = {};
+    std::array<void *, GGML_MAX_SRC> src_buffer = {};
+    const char * srci_name[GGML_MAX_SRC] = {"src0", "src1", "src2", "src3", "src4", "src5", "src6", "src7", "src8", "src9"};
 
     struct ggml_tensor * tensor_clone = nullptr;
 
-    for (int i = 0; i < 6; i++) {
+    for (int i = 0; i < GGML_MAX_SRC; i++) {
         ggml_tensor * srci = tensor->src[i];
         if (fused_rms_norm_mul) {
             rms_norm_idx = tensor->src[0]->op == GGML_OP_RMS_NORM ? 0 : 1;
@@ -13537,6 +13703,9 @@ static void ggml_vk_check_results_0(ggml_backend_vk_context * ctx, ggml_cgraph *
         src_clone[2]);
     } else if (tensor->op == GGML_OP_ADD_ID) {
         tensor_clone = ggml_add_id(ggml_ctx, src_clone[0], src_clone[1], src_clone[2]);
+    } else if (tensor->op == GGML_OP_SSM_SCAN) {
+        tensor_clone = ggml_ssm_scan(ggml_ctx, src_clone[0], src_clone[1], src_clone[2],
+                                     src_clone[3], src_clone[4], src_clone[5], src_clone[6]);
     }
     else {
         std::cerr << "Missing vk_check_results OP: " << ggml_op_name(tensor->op) << std::endl;
@@ -13558,7 +13727,7 @@ static void ggml_vk_check_results_0(ggml_backend_vk_context * ctx, ggml_cgraph *
     memcpy(comp_result, tensor_clone->data, comp_size);
     memcpy(comp_nb, tensor_clone->nb, sizeof(size_t) * GGML_MAX_DIMS);
 
-    for (int i = 0; i < 6; i++) {
+    for (int i = 0; i < GGML_MAX_SRC; i++) {
         if (src_buffer[i] != nullptr) {
             free(src_buffer[i]);
         }

ggml/src/ggml-vulkan/vulkan-shaders/ssm_scan.comp

@@ -0,0 +1,125 @@
+#version 450
+
+#extension GL_EXT_control_flow_attributes : require
+
+#include "types.glsl"
+
+layout(constant_id = 0) const uint D_STATE = 128;
+layout(constant_id = 1) const uint SUBGROUP_SIZE = 32;
+layout(constant_id = 2) const uint SPLIT_H = 16;
+
+layout(local_size_x_id = 0, local_size_y = 1, local_size_z = 1) in;
+
+layout(binding = 0) readonly buffer Src0 { float s0[]; };
+layout(binding = 1) readonly buffer Src1 { float x[]; };
+layout(binding = 2) readonly buffer Src2 { float dt[]; };
+layout(binding = 3) readonly buffer Src3 { float A[]; };
+layout(binding = 4) readonly buffer Src4 { float B[]; };
+layout(binding = 5) readonly buffer Src5 { float C[]; };
+layout(binding = 6) readonly buffer Src6 { int ids[]; };
+layout(binding = 7) buffer Dst { float d[]; };
+
+layout(push_constant) uniform PushConstants {
+    uint nb02; uint nb03; uint nb12; uint nb13;
+    uint nb21; uint nb22; uint nb31;
+    uint nb42; uint nb43; uint nb52; uint nb53;
+    uint s_off;
+    uint n_head;
+    uint d_head;
+    uint n_group;
+    uint n_tok;
+};
+
+float softplus(float x) {
+    if (x <= 20.0) {
+        return log(1.0 + exp(x));
+    } else {
+        return x;
+    }
+}
+
+shared float stateC[SPLIT_H * D_STATE];
+
+void main() {
+    const uint tid = gl_LocalInvocationID.x;
+    const uint head_idx = (gl_WorkGroupID.x * SPLIT_H) / d_head;
+    const uint head_off = ((gl_WorkGroupID.x * SPLIT_H) % d_head) * 4;
+    const uint seq_idx = gl_WorkGroupID.y;
+
+    const uint group_off = (head_idx / (n_head / n_group)) * D_STATE * 4;
+    const uint s0_base_idx = (uint(ids[seq_idx]) * nb03 + head_idx * nb02 + head_off * D_STATE) / 4;
+    const uint x_base_idx = (seq_idx * nb13 + gl_WorkGroupID.x * SPLIT_H * 4) / 4;
+    const uint dt_base_idx = (seq_idx * nb22 + head_idx * 4) / 4;
+    const uint A_base_idx = (head_idx * nb31) / 4;
+    const uint B_base_idx = (seq_idx * nb43 + group_off) / 4;
+    const uint C_base_idx = (seq_idx * nb53 + group_off) / 4;
+    const uint y_base_idx = seq_idx * n_tok * n_head * d_head + gl_WorkGroupID.x * SPLIT_H;
+    const uint s_base_idx = (s_off + seq_idx * nb03 + head_idx * nb02 + head_off * D_STATE) / 4;
+
+    const uint stride_x = nb12 / 4;
+    const uint stride_dt = nb21 / 4;
+    const uint stride_B = nb42 / 4;
+    const uint stride_C = nb52 / 4;
+    const uint stride_y = n_head * d_head;
+
+    float state[SPLIT_H];
+    [[unroll]] for (uint j = 0; j < SPLIT_H; j++) {
+        state[j] = s0[s0_base_idx + j * D_STATE + tid];
+    }
+
+    for (uint i = 0; i < n_tok; i++) {
+        const float dt_soft_plus = softplus(dt[dt_base_idx + i * stride_dt]);
+
+        const float dA = exp(dt_soft_plus * A[A_base_idx]);
+
+        const float B_val = B[B_base_idx + i * stride_B + tid];
+        const float C_val = C[C_base_idx + i * stride_C + tid];
+
+        [[unroll]] for (uint j = 0; j < SPLIT_H; j++) {
+            const float x_dt = x[x_base_idx + i * stride_x + j] * dt_soft_plus;
+
+            state[j] = (state[j] * dA) + (B_val * x_dt);
+
+            stateC[j * D_STATE + tid] = state[j] * C_val;
+        }
+
+        barrier();
+        for (uint w = D_STATE; w > SUBGROUP_SIZE; w >>= 1) {
+            [[unroll]] for (uint j = 0; j < ((w >> 1) * SPLIT_H + D_STATE - 1) / D_STATE; j++) {
+                const uint k = (tid % (w >> 1)) +
+                              (D_STATE * (tid / (w >> 1))) +
+                              j * D_STATE * (D_STATE / (w >> 1));
+                if (k < SPLIT_H * D_STATE && (k + (w >> 1)) < SPLIT_H * D_STATE) {
+                    stateC[k] += stateC[k + (w >> 1)];
+                }
+            }
+            barrier();
+        }
+
+        [[unroll]] for (uint j = 0; j < SPLIT_H / (D_STATE / SUBGROUP_SIZE); j++) {
+            const uint idx = (tid % SUBGROUP_SIZE) +
+                            D_STATE * (tid / SUBGROUP_SIZE) +
+                            j * D_STATE * (D_STATE / SUBGROUP_SIZE);
+
+            uint lane = tid % SUBGROUP_SIZE;
+
+            [[unroll]] for (uint offset = SUBGROUP_SIZE / 2; offset > 0; offset >>= 1) {
+                if (lane < offset) {
+                    stateC[idx] += stateC[idx + offset];
+                }
+                barrier();
+            }
+
+            if (tid % SUBGROUP_SIZE == 0) {
+                const uint k = tid / SUBGROUP_SIZE + j * (D_STATE / SUBGROUP_SIZE);
+                d[y_base_idx + i * stride_y + k] = stateC[idx];
+            }
+        }
+
+        barrier();
+    }
+
+    [[unroll]] for (uint j = 0; j < SPLIT_H; j++) {
+        d[s_base_idx + j * D_STATE + tid] = state[j];
+    }
+}