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-rw-r--r--ggml/src/CMakeLists.txt1
-rw-r--r--ggml/src/ggml-cuda.cu31
2 files changed, 28 insertions, 4 deletions
diff --git a/ggml/src/CMakeLists.txt b/ggml/src/CMakeLists.txt
index b0db417d..5ecdb4f1 100644
--- a/ggml/src/CMakeLists.txt
+++ b/ggml/src/CMakeLists.txt
@@ -382,6 +382,7 @@ if (GGML_CUDA)
add_compile_definitions(GGML_CUDA_MMV_Y=${GGML_CUDA_MMV_Y})
add_compile_definitions(K_QUANTS_PER_ITERATION=${GGML_CUDA_KQUANTS_ITER})
add_compile_definitions(GGML_CUDA_PEER_MAX_BATCH_SIZE=${GGML_CUDA_PEER_MAX_BATCH_SIZE})
+ add_compile_definitions(GGML_CUDA_MIN_BATCH_OFFLOAD=${GGML_CUDA_MIN_BATCH_OFFLOAD})
if (GGML_CUDA_USE_GRAPHS)
add_compile_definitions(GGML_CUDA_USE_GRAPHS)
diff --git a/ggml/src/ggml-cuda.cu b/ggml/src/ggml-cuda.cu
index 0961e2bd..da3dc334 100644
--- a/ggml/src/ggml-cuda.cu
+++ b/ggml/src/ggml-cuda.cu
@@ -3656,10 +3656,33 @@ GGML_CALL static bool ggml_backend_cuda_supports_buft(ggml_backend_t backend, gg
}
GGML_CALL static bool ggml_backend_cuda_offload_op(ggml_backend_t backend, const ggml_tensor * op) {
- const int min_batch_size = 32;
-
- return (op->ne[1] >= min_batch_size && op->op != GGML_OP_GET_ROWS) ||
- (op->ne[2] >= min_batch_size && (op->op == GGML_OP_MUL_MAT_ID || op->op == GGML_OP_MOE_FUSED_UP_GATE));
+ constexpr int min_batch_size = GGML_CUDA_MIN_BATCH_OFFLOAD;
+
+ // Why do we want to do this? The heuristics that the batch must have more than min_batch_size tokens to be worth it
+ // offloading the required model weights comes from dense models. For MoE models, the average number of tokens
+ // each expert deals with in a batch is (active_experts / total_experts) * batch_size. Hence, according to the
+ // learned heuristics, we need (active_experts / total_experts) * batch_size >= min_batch_size.
+ // Rearranging we get
+ //
+ // batch_size * active_experts >= min_batch_size * total_experts
+ //
+ // as the condition for offloading model weights resinding in RAM to the GPU.
+ // In this case, the number of tokens is not as usual in op->ne[1] but rather in op->ne[2].
+ if (op->op == GGML_OP_MUL_MAT_ID || op->op == GGML_OP_MOE_FUSED_UP_GATE) {
+ auto ids = op->op == GGML_OP_MUL_MAT_ID ? op->src[2] : op->src[3];
+ int64_t batch_size = op->ne[2];
+ if (batch_size < min_batch_size) return false;
+ int64_t n_experts_tot = op->src[0]->ne[2];
+ int64_t n_experts_active = ids->ne[0];
+ //printf("%s(%s): op->ne[2] = %ld, n_experts_tot = %ld, n_experts_active = %ld, ids: %s, %ld x %ld x %ld x %ld\n", __func__, op->name, op->ne[2], n_experts_tot, n_experts_active, ids->name, ids->ne[0], ids->ne[1], ids->ne[2], ids->ne[3]);
+ return batch_size*n_experts_active >= min_batch_size*n_experts_tot;
+ }
+
+ return op->ne[1] >= min_batch_size && op->op != GGML_OP_GET_ROWS;
+
+ // Original:
+ //return (op->ne[1] >= min_batch_size && op->op != GGML_OP_GET_ROWS) ||
+ // (op->ne[2] >= min_batch_size && (op->op == GGML_OP_MUL_MAT_ID || op->op == GGML_OP_MOE_FUSED_UP_GATE));
GGML_UNUSED(backend);
}