Memory intensive native plugin seeing ~6x slowdown

Hello all,

I've got a C++ library that I'm using with an iOS native plugin under Unity. The plugin is very memory intensive even running under just iOS -- allocating/deallocating memory and just overall memory pressure. When I run it as a native plugin though, I'm seeing a near 6x slowdown and it seems to mostly stem from memory allocation/deallocation. Profiling under Xcode I'm seeing a lot of time spent in MemoryManager::Deallocate()and BaseAllocator::TryDeallocate() (both of which are definitely not my classes). These are coming from creating std::vector's and also cv::Mat's. It seems as though my code is running on top of some sort of layer setup by Unity? This seems contrary to the point of a native plugin though.

Am I doing something wrong here or is this to be expected?

Thanks!