From 2eee6c866c89bcb101693c8b33fa6e1a7f98932c Mon Sep 17 00:00:00 2001
From: Georgi Gerganov <ggerganov@gmail.com>
Date: Wed, 28 Jan 2026 09:15:11 +0200
Subject: [PATCH] CUDA: tune GLM 4.7 Flash FA kernel selection logic (DGX
 Spark) (#19142)

---
 ggml/src/ggml-cuda/common.cuh | 1 +
 ggml/src/ggml-cuda/fattn.cu   | 8 ++++++++
 2 files changed, 9 insertions(+)

diff --git a/ggml/src/ggml-cuda/common.cuh b/ggml/src/ggml-cuda/common.cuh
index 09a491a836..3335f443ae 100644
--- a/ggml/src/ggml-cuda/common.cuh
+++ b/ggml/src/ggml-cuda/common.cuh
@@ -53,6 +53,7 @@
 // While BW spans CC 1000, 1100 & 1200, we are integrating Tensor Core instructions available to 1200 family, see
 // https://docs.nvidia.com/cutlass/media/docs/cpp/blackwell_functionality.html#blackwell-sm120-gemms
 #define GGML_CUDA_CC_BLACKWELL       1200
+#define GGML_CUDA_CC_DGX_SPARK       1210
 #define GGML_CUDA_CC_RUBIN           1300
 #define GGML_CUDA_CC_OFFSET_AMD      0x1000000
 #define GGML_CUDA_CC_OFFSET_MTHREADS 0x0100000
diff --git a/ggml/src/ggml-cuda/fattn.cu b/ggml/src/ggml-cuda/fattn.cu
index b061fdf9a2..fe18ff6c7d 100644
--- a/ggml/src/ggml-cuda/fattn.cu
+++ b/ggml/src/ggml-cuda/fattn.cu
@@ -147,6 +147,14 @@ static void ggml_cuda_flash_attn_ext_mma_f16(ggml_backend_cuda_context & ctx, gg
             GGML_ASSERT(Q->ne[2] % K->ne[2] == 0);
             const int gqa_ratio = Q->ne[2] / K->ne[2];
             if (gqa_ratio == 20) { // GLM 4.7 Flash
+                if (cc >= GGML_CUDA_CC_DGX_SPARK) {
+                    if (Q->ne[1] <= 8) {
+                        ggml_cuda_flash_attn_ext_mma_f16_switch_ncols1<576, 512, 16>(ctx, dst);
+                        break;
+                    }
+                    ggml_cuda_flash_attn_ext_mma_f16_switch_ncols1<576, 512, 4>(ctx, dst);
+                    break;
+                }
                 if (cc >= GGML_CUDA_CC_BLACKWELL) {
                     if (Q->ne[1] <= 4 && K->ne[1] >= 65536) {
                         ggml_cuda_flash_attn_ext_mma_f16_switch_ncols1<576, 512, 16>(ctx, dst);