ggml-cuda: Allow transpose-free gemmv computation (#26171)

When matrix's weights are shaped 1xK is leverage a transpose-free
computation to use mat_mul_vec_f.

diff --git a/ggml/src/ggml-cuda/ggml-cuda.cu b/ggml/src/ggml-cuda/ggml-cuda.cu
index d22b5657d9d2623734403f931ffb7c1b70fb7725..3e2c622951b5d32b25da4ae461f31cb778ee0e96 100644 (file)
--- a/ggml/src/ggml-cuda/ggml-cuda.cu
+++ b/ggml/src/ggml-cuda/ggml-cuda.cu
@@ -1836,6 +1836,20 @@ static void ggml_cuda_mul_mat(ggml_backend_cuda_context & ctx, const ggml_tensor
         ggml_cuda_mul_mat_vec_f(ctx, src0, src1, nullptr, dst);
         return;
     }
+    // A transposed vector can still use MMVQ (i.e. ne01 == 1)
+    if (ne01 == 1 && ne11 > MMVF_MAX_BATCH_SIZE && ne2 == 1 && ne3 == 1
+            && src0->type == GGML_TYPE_F32
+            && ggml_is_contiguous(src0) && ggml_is_contiguous(src1) && ggml_is_contiguous(dst)
+            && ggml_cuda_should_use_mmvf(src1->type, cc, src1->ne, src1->nb, /*ne11 =*/ 1)) {
+        ggml_tensor dst_vec = *dst;
+        dst_vec.ne[0] = ne11;
+        dst_vec.ne[1] = 1;
+        dst_vec.nb[1] = dst_vec.nb[0]*ne11;
+        dst_vec.nb[2] = dst_vec.nb[1];
+        dst_vec.nb[3] = dst_vec.nb[1];
+        ggml_cuda_mul_mat_vec_f(ctx, src1, src0, nullptr, &dst_vec);
+        return;
+    }
     if (ggml_cuda_should_use_mmf(src0->type, cc, warp_size, src0->ne, src0->nb, ne11, /*mul_mat_id =*/ false)) {
         ggml_cuda_mul_mat_f(ctx, src0, src1, nullptr, dst);
         return;

diff --git a/tests/test-backend-ops.cpp b/tests/test-backend-ops.cpp
index ef18ecef8a4d07fb9ec24d28b6e2576b6ec1a966..e8d0e00d5b8bb5e17c9f4c19dcebe21c44fb83f0 100644 (file)
--- a/tests/test-backend-ops.cpp
+++ b/tests/test-backend-ops.cpp
@@ -8838,6 +8838,10 @@ static std::vector<std::unique_ptr<test_case>> make_test_cases_eval() {
     test_cases.emplace_back(new test_mul_mat(GGML_TYPE_Q8_0, GGML_TYPE_F32, 2880, 32, 2880, {1, 1}, {1, 1}));
     test_cases.emplace_back(new test_mul_mat(GGML_TYPE_MXFP4, GGML_TYPE_F32, 2880, 32, 2880, {1, 1}, {1, 1}));
 
+    // m == 1, with n on both sides of MMVF_MAX_BATCH_SIZE (8): mmvf below, operand swap above
+    for (int64_t n : {1, 7, 8, 9, 16, 128, 512}) {
+        test_cases.emplace_back(new test_mul_mat(GGML_TYPE_F32, GGML_TYPE_F32, 1, n, 2048, {1, 1}, {1, 1}));
+    }
 
 #if 0
     {