all matrix multiplication backend

Author: slaren

ggml-blas.cpp

@@ -1,6 +1,8 @@
 #include "ggml-blas.h"
 #include "ggml-backend-impl.h"
 
+#include <atomic>
+#include <cassert>
 #include <future>
 #include <vector>
 
@@ -22,6 +24,7 @@ struct ggml_backend_blas_context {
 #ifndef GGML_USE_OPENMP
     std::vector<std::future<void>> tasks;
 #endif
+    std::atomic<int> current_chunk;
 };
 
 // helper function to determine if it is better to use BLAS or not
@@ -48,6 +51,265 @@ static bool ggml_backend_blas_use_blas(const struct ggml_tensor * dst) {
     return false;
 }
 
+static void ggml_compute_forward_mul_mat_one_chunk(
+    ggml_backend_blas_context * ctx,
+    struct ggml_tensor * dst,
+    const int64_t num_rows_per_vec_dot,
+    const int64_t ir0_start,
+    const int64_t ir0_end,
+    const int64_t ir1_start,
+    const int64_t ir1_end) {
+
+    const struct ggml_tensor * src0 = dst->src[0];
+    const struct ggml_tensor * src1 = dst->src[1];
+
+    GGML_TENSOR_BINARY_OP_LOCALS
+
+    const enum ggml_type type = src0->type;
+
+    const bool src1_cont = ggml_is_contiguous(src1);
+
+    const ggml_type_traits_t * type_traits = ggml_internal_get_type_traits_ptr(type);
+
+    ggml_vec_dot_t    const vec_dot = type_traits->vec_dot;
+    enum ggml_type    const vec_dot_type = type_traits->vec_dot_type;
+
+    // broadcast factors
+    const int64_t r2 = ne12 / ne02;
+    const int64_t r3 = ne13 / ne03;
+
+    //printf("ir0_start = %6lld, ir0_end = %6lld, ir1_start = %6lld, ir1_end = %6lld\n", ir0_start, ir0_end, ir1_start, ir1_end);
+
+    // threads with no work simply yield (not sure if it helps)
+    if (ir0_start >= ir0_end || ir1_start >= ir1_end) {
+        return;
+    }
+
+    const void * wdata = (src1->type == vec_dot_type) ? src1->data : ctx->work_data.get();
+    const size_t row_size = ggml_row_size(vec_dot_type, ne10);
+
+    assert(ne12 % ne02 == 0);
+    assert(ne13 % ne03 == 0);
+
+    // block-tiling attempt
+    const int64_t blck_0 = 16;
+    const int64_t blck_1 = 16;
+
+    const size_t src1_col_stride = src1_cont || src1->type != vec_dot_type ? row_size : nb11;
+
+    // attempt to reduce false-sharing (does not seem to make a difference)
+    // 16 * 2, accounting for mmla kernels
+    float tmp[32];
+
+    for (int64_t iir1 = ir1_start; iir1 < ir1_end; iir1 += blck_1) {
+        for (int64_t iir0 = ir0_start; iir0 < ir0_end; iir0 += blck_0) {
+            for (int64_t ir1 = iir1; ir1 < iir1 + blck_1 && ir1 < ir1_end; ir1 += num_rows_per_vec_dot) {
+                const int64_t i13 = (ir1 / (ne12 * ne1));
+                const int64_t i12 = (ir1 - i13 * ne12 * ne1) / ne1;
+                const int64_t i11 = (ir1 - i13 * ne12 * ne1 - i12 * ne1);
+
+                // broadcast src0 into src1
+                const int64_t i03 = i13 / r3;
+                const int64_t i02 = i12 / r2;
+
+                const int64_t i1 = i11;
+                const int64_t i2 = i12;
+                const int64_t i3 = i13;
+
+                const char * src0_row = (const char*)src0->data + (0 + i02 * nb02 + i03 * nb03);
+
+                // desc: when src1 is not a contiguous memory block we have to calculate the offset using the strides
+                //       if it is, then we have either copied the data to params->wdata and made it contiguous or we are using
+                //       the original src1 data pointer, so we should index using the indices directly
+                // TODO: this is a bit of a hack, we should probably have a better way to handle this
+                const char * src1_col = (const char*)wdata +
+                    (src1_cont || src1->type != vec_dot_type
+                        ? (i11 + i12 * ne11 + i13 * ne12 * ne11) * row_size
+                        : (i11 * nb11 + i12 * nb12 + i13 * nb13));
+                float * dst_col = (float*)((char*)dst->data + (i1 * nb1 + i2 * nb2 + i3 * nb3));
+
+                //for (int64_t ir0 = iir0; ir0 < iir0 + blck_0 && ir0 < ir0_end; ++ir0) {
+                //    vec_dot(ne00, &dst_col[ir0], src0_row + ir0*nb01, src1_col);
+                //}
+
+                for (int64_t ir0 = iir0; ir0 < iir0 + blck_0 && ir0 < ir0_end; ir0 += num_rows_per_vec_dot) {
+                    vec_dot(ne00, &tmp[ir0 - iir0], (num_rows_per_vec_dot > 1 ? 16 : 0), src0_row + ir0 * nb01, (num_rows_per_vec_dot > 1 ? nb01 : 0), src1_col, (num_rows_per_vec_dot > 1 ? src1_col_stride : 0), num_rows_per_vec_dot);
+                }
+
+                for (int cn = 0; cn < num_rows_per_vec_dot; ++cn) {
+                    memcpy(&dst_col[iir0 + cn * nb1 / nb0], tmp + (cn * 16), (std::min(iir0 + blck_0, ir0_end) - iir0) * sizeof(float));
+                }
+            }
+        }
+    }
+}
+
+static void ggml_compute_forward_mul_mat(
+              ggml_backend_blas_context * ctx,
+              struct ggml_tensor * dst) {
+
+    const struct ggml_tensor * src0 = dst->src[0];
+    const struct ggml_tensor * src1 = dst->src[1];
+
+
+    GGML_TENSOR_BINARY_OP_LOCALS
+
+    const enum ggml_type type = src0->type;
+
+    const ggml_type_traits_t * type_traits = ggml_internal_get_type_traits_ptr(type);
+    const ggml_type_traits_t * type_traits_vec_dot = ggml_internal_get_type_traits_ptr(type_traits->vec_dot_type);
+    enum ggml_type    const vec_dot_type          = type_traits->vec_dot_type;
+    ggml_from_float_t const from_float_to_vec_dot = type_traits_vec_dot->from_float;
+    int64_t           const vec_dot_num_rows      = type_traits->nrows;
+
+    GGML_ASSERT(ne0 == ne01);
+    GGML_ASSERT(ne1 == ne11);
+    GGML_ASSERT(ne2 == ne12);
+    GGML_ASSERT(ne3 == ne13);
+
+    // we don't support permuted src0 or src1
+    GGML_ASSERT(nb00 == ggml_type_size(type));
+    GGML_ASSERT(nb10 == ggml_type_size(src1->type));
+
+    // dst cannot be transposed or permuted
+    GGML_ASSERT(nb0 == sizeof(float));
+    GGML_ASSERT(nb0 <= nb1);
+    GGML_ASSERT(nb1 <= nb2);
+    GGML_ASSERT(nb2 <= nb3);
+
+    // broadcast factors
+    const int64_t r2 = ne12 / ne02;
+    const int64_t r3 = ne13 / ne03;
+    GGML_UNUSED(r2);
+    GGML_UNUSED(r3);
+
+    // nb01 >= nb00 - src0 is not transposed
+    //   compute by src0 rows
+
+    if (src1->type != vec_dot_type) {
+        const size_t row_size = ggml_row_size(vec_dot_type, ne10);
+        if (ctx->work_size < ne13*ne12*ne11*row_size) {
+            ctx->work_data.reset(new char[ne13*ne12*ne11*row_size]);
+            ctx->work_size = ne13*ne12*ne11*row_size;
+        }
+        char * wdata = ctx->work_data.get();
+
+        GGML_ASSERT(src1->type == GGML_TYPE_F32);
+        int block_size = ggml_blck_size(vec_dot_type);
+        int type_size = ggml_type_size(vec_dot_type);
+
+        for (int64_t i13 = 0; i13 < ne13; ++i13) {
+            for (int64_t i12 = 0; i12 < ne12; ++i12) {
+                for (int64_t i11 = 0; i11 < ne11; ++i11) {
+                    //from_float_to_vec_dot((float *)((char *) src1->data + i13*nb13 + i12*nb12 + i11*nb11), (void *) wdata, ne10);
+                    //#pragma omp parallel num_threads(ctx->n_threads)
+                    {
+                        int nth = omp_get_num_threads();
+                        int ith = omp_get_thread_num();
+                        int blocks_per_thread = (ne10 + block_size - 1) / block_size / nth;
+                        int i10_start = ith * blocks_per_thread * block_size;
+                        int i10_end = std::min(i10_start + blocks_per_thread * block_size, (int)ne10);
+                        //printf("thread %d/%d: i10_start = %d, i10_end = %d\n", ith, nth, i10_start, i10_end);
+                        from_float_to_vec_dot((float *)((char *) src1->data + i13*nb13 + i12*nb12 + i11*nb11 + i10_start*nb10),
+                                                (void *) ((char *) wdata + (type_size*i10_start/block_size)),
+                                                i10_end - i10_start);
+
+                    }
+
+                    wdata += row_size;
+                }
+            }
+        }
+    }
+
+    // This is the size of the first dimension of the result, so we can iterate that way. (see the ASSERT above, these are the same numbers)
+    const int64_t nr0 = ne0;
+
+    // This is the size of the rest of the dimensions of the result
+    const int64_t nr1 = ne1 * ne2 * ne3;
+
+    // dot kernels can handle 1 row and col at a time, but mmla kernels can process 2 rows and cols
+    int64_t num_rows_per_vec_dot = vec_dot_num_rows;
+    // TODO: currently the mmla kernels support only even numbered rows/cols.
+    // this check can be removed once they are extended to support odd numbered rows/cols too
+    if ((nr0 % 2 != 0) || (ne11 % 2 != 0)) {
+        num_rows_per_vec_dot = 1;
+    }
+
+    // Now select a reasonable chunk size.
+    int chunk_size = 16;
+
+    // We need to step up the size if it's small
+    if (nr0 == 1 || nr1 == 1) {
+        chunk_size = 64;
+    }
+
+    // distribute the work across the inner or outer loop based on which one is larger
+    // The number of chunks in the 0/1 dim.
+    // CEIL(nr0/chunk_size)
+    int64_t nchunk0 = (nr0 + chunk_size - 1) / chunk_size;
+    int64_t nchunk1 = (nr1 + chunk_size - 1) / chunk_size;
+
+    // If the chunking is poor for the number of threads on this setup, scrap the whole plan.  Re-chunk it by thread.
+    //   Also, chunking by thread was measured to have perform better on NUMA systems.  See https://github.com/ggerganov/llama.cpp/pull/6915
+    //   In theory, chunking should be just as useful on NUMA and non NUMA systems, but testing disagreed with that.
+
+    //const int ith = 0; // params->ith;
+    const int nth = ctx->n_threads;
+
+    // Every thread starts at ith, so the first unprocessed chunk is nth.  This save a bit of coordination right at the start.
+    ctx->current_chunk.store(nth);
+
+    if (nchunk0 * nchunk1 < nth * 4 || ggml_is_numa()) {
+        // distribute the thread work across the inner or outer loop based on which one is larger
+        nchunk0 = nr0 > nr1 ? nth : 1; // parallelize by src0 rows
+        nchunk1 = nr0 > nr1 ? 1 : nth; // parallelize by src1 rows
+    }
+
+    // The number of elements in each chunk
+    const int64_t dr0 = (nr0 + nchunk0 - 1) / nchunk0;
+    const int64_t dr1 = (nr1 + nchunk1 - 1) / nchunk1;
+
+    //if (ith == 0)
+    //    printf("MUL_MAT = [%d, %d, %d, %d] x [%d, %d, %d, %d] = %d x %d = %d.  Fp Ops/Ch %d\n", ne00, ne01, ne02, ne03, ne10, ne11, ne12, ne13, nchunk0, nchunk1, nchunk0 * nchunk1, ne00 * nr0 * nr1 / nchunk0 / nchunk1);
+
+    // The first chunk comes from our thread_id, the rest will get auto-assigned.
+    if (nth > 1) {
+        #pragma omp parallel num_threads(nth)
+        {
+            int current_chunk = omp_get_thread_num();
+
+            while (current_chunk < nchunk0 * nchunk1) {
+                const int64_t ith0 = current_chunk % nchunk0;
+                const int64_t ith1 = current_chunk / nchunk0;
+
+                const int64_t ir0_start = dr0 * ith0;
+                const int64_t ir0_end = std::min(ir0_start + dr0, nr0);
+
+                const int64_t ir1_start = dr1 * ith1;
+                const int64_t ir1_end = std::min(ir1_start + dr1, nr1);
+
+                ggml_compute_forward_mul_mat_one_chunk(ctx, dst, num_rows_per_vec_dot, ir0_start, ir0_end, ir1_start, ir1_end);
+
+                if (nth >= nchunk0 * nchunk1) {
+                    break;
+                }
+
+                current_chunk = ctx->current_chunk.fetch_add(1);
+            }
+        }
+    } else {
+        ggml_compute_forward_mul_mat_one_chunk(ctx, dst, num_rows_per_vec_dot, 0, nr0, 0, nr1);
+    }
+
+#ifdef GGML_PERF
+    // These numbers are useful when trying to measure how well the threading scheduling works.
+    //int64_t workSize = (ne01 * ne11 * ne12 * ne13 * ne00) / nchunk0 / nchunk1;
+    //float time = (ggml_perf_time_us() - t0);
+    //printf("MUL_MAT = %f ms, [%d, %d, %d, %d] x [%d, %d, %d, %d] = %I64u, %f ops/usec in %d chunks.\n", time / 1000.0, ne00, ne01, ne02, ne03, ne10, ne11, ne12, ne13, workSize, (float)workSize/time, chunks_executed);
+#endif
+}
+
 static void ggml_backend_blas_mul_mat(ggml_backend_blas_context * ctx, struct ggml_tensor * dst) {
     const struct ggml_tensor * src0 = dst->src[0];
     const struct ggml_tensor * src1 = dst->src[1];
@@ -255,7 +517,8 @@ GGML_CALL static enum ggml_status ggml_backend_blas_graph_compute(ggml_backend_t
 
         switch (node->op) {
             case GGML_OP_MUL_MAT:
-                ggml_backend_blas_mul_mat(ctx, node);
+                //ggml_backend_blas_mul_mat(ctx, node);
+                ggml_compute_forward_mul_mat(ctx, node);
                 break;
 
             case GGML_OP_OUT_PROD:
@@ -281,6 +544,10 @@ GGML_CALL static enum ggml_status ggml_backend_blas_graph_compute(ggml_backend_t
 }
 
 GGML_CALL static bool ggml_backend_blas_supports_op(ggml_backend_t backend, const struct ggml_tensor * op) {
+
+    return op->op == GGML_OP_MUL_MAT || op->op == GGML_OP_OUT_PROD;
+
+    /*
     const struct ggml_tensor * src0 = op->src[0];
     const struct ggml_tensor * src1 = op->src[1];
 
@@ -291,6 +558,7 @@ GGML_CALL static bool ggml_backend_blas_supports_op(ggml_backend_t backend, cons
                                           ggml_is_matrix(src1) &&
                                           ggml_is_contiguous(src0) &&
                                           (ggml_is_contiguous(src1) || ggml_is_transposed(src1)));
+    */
 
     GGML_UNUSED(backend);
 }

ggml.c

@@ -911,6 +911,11 @@ ggml_type_traits_t ggml_internal_get_type_traits(enum ggml_type type) {
     return type_traits[type];
 }
 
+const ggml_type_traits_t * ggml_internal_get_type_traits_ptr(enum ggml_type type) {
+    GGML_ASSERT(type < GGML_TYPE_COUNT);
+    return &type_traits[type];
+}
+
 //
 // simd mappings
 //

ggml.h

@@ -2447,6 +2447,8 @@ extern "C" {
 
     GGML_API ggml_type_traits_t ggml_internal_get_type_traits(enum ggml_type type);
 
+    GGML_API const ggml_type_traits_t * ggml_internal_get_type_traits_ptr(enum ggml_type type);
+
 #ifdef  __cplusplus
 }
 #endif