diff --git a/cpp/bench/random/make_blobs.cu b/cpp/bench/random/make_blobs.cu
index fdd4ef61d2..950d80c499 100644
--- a/cpp/bench/random/make_blobs.cu
+++ b/cpp/bench/random/make_blobs.cu
@@ -25,6 +25,12 @@ struct make_blobs_inputs {
   bool row_major;
 };  // struct make_blobs_inputs
 
+inline auto operator<<(std::ostream& os, const make_blobs_inputs& p) -> std::ostream&
+{
+  os << p.rows << "#" << p.cols << "#" << p.clusters << "#" << p.row_major;
+  return os;
+}
+
 template <typename T>
 struct make_blobs : public fixture {
   make_blobs(const make_blobs_inputs& p)
@@ -34,6 +40,10 @@ struct make_blobs : public fixture {
 
   void run_benchmark(::benchmark::State& state) override
   {
+    std::ostringstream label_stream;
+    label_stream << params;
+    state.SetLabel(label_stream.str());
+
     loop_on_state(state, [this]() {
       raft::random::make_blobs(data.data(),
                                labels.data(),
diff --git a/cpp/include/raft/random/detail/make_blobs.cuh b/cpp/include/raft/random/detail/make_blobs.cuh
index 212245a9bf..68c2d56599 100644
--- a/cpp/include/raft/random/detail/make_blobs.cuh
+++ b/cpp/include/raft/random/detail/make_blobs.cuh
@@ -156,8 +156,10 @@ void generate_data(DataT* out,
                    const DataT cluster_std_scalar,
                    raft::random::RngState& rng_state)
 {
-  IdxT items   = n_rows * n_cols;
-  IdxT nBlocks = (items + 127) / 128;
+  constexpr IdxT block_size = 128;
+  IdxT items                = n_rows * n_cols;
+  // Choose a grid size so that each thread can write two output values.
+  IdxT nBlocks = ceildiv<IdxT>(items, 2 * block_size);
   // parentheses needed here for kernel, otherwise macro interprets the arguments
   // of triple chevron notation as macro arguments
   RAFT_CALL_RNG_FUNC(rng_state,