improve group deconvolution openmp scheduler

src/layer/deconvolutiondepthwise.cpp

@@ -152,14 +152,18 @@ int DeconvolutionDepthWise::forward(const Mat& bottom_blob, Mat& top_blob, const
         const int channels_g = channels / group;
         const int num_output_g = num_output / group;
 
+#ifdef _WIN32
         #pragma omp parallel for num_threads(opt.num_threads)
+#else // _WIN32
+        #pragma omp parallel for collapse(2) num_threads(opt.num_threads)
+#endif // _WIN32
         for (int g = 0; g < group; g++)
         {
-            const float* weight_data_ptr = (const float*)weight_data + maxk * channels_g * num_output_g * g;
             for (int p = 0; p < num_output_g; p++)
             {
                 Mat out = top_blob_bordered.channel(g * num_output_g + p);
 
+                const float* weight_data_ptr = (const float*)weight_data + maxk * channels_g * num_output_g * g;
                 const float bias = bias_term ? bias_data[g * num_output_g + p] : 0.f;
 
                 out.fill(bias);