hipCUB Device Radix Sort Example

Description

This simple program showcases the usage of the hipcub::DeviceRadixSort::SortPairs function.

Application flow

1. Host side data is instantiated in std::vector<float> and std::vector<int> as key-value pairs.
2. Device side storage is allocated using hipMalloc.
3. Data is copied from host to device using hipMemcpy.
4. hipCUB::DeviceRadixSort::SortPairs makes use of temporary memory on the device that needs to be allocated manually. A first call to hipcub::DeviceRadixSort::SortPairs (with d_temp_storage set to null) calculates the size in bytes needed for the temporary storage and stores it in the variable temp_storage_bytes.
5. temp_storage_bytes is used to allocate device memory in d_temp_storage using hipMalloc.
6. Finally a second call to hipcub::DeviceRadixSort::SortPairs is invoked that sorts the pairs on the basis of keys.
7. Result is transferred from device to host.
8. Free all device side memory using hipFree

Key APIs and Concepts

• The device-level API provided by hipCUB is used in this example. It performs global device level operations (in this case pair sorting using hipcub::DeviceRadixSort::SortPairs) on the GPU.

Demonstrated API Calls

hipCUB

• hipcub::DoubleBuffer
• hipcub::DeviceRadixSort::SortPairs

HIP runtime

• hipGetErrorString
• hipMalloc
• hipMemcpy
• hipFree