KvikIO (pronounced "kuh-VICK-eye-oh", see here for pronunciation of kvik) is a Python and C++ library for high performance file IO. It provides C++ and Python bindings to cuFile, which enables GPUDirect Storage (GDS). KvikIO also works efficiently when GDS isn't available and can read/write both host and device data seamlessly.
- Object oriented API of cuFile with C++/Python exception handling.
- A Python Zarr backend for reading and writing GPU data to file seamlessly.
- Concurrent reads and writes using an internal thread pool.
- Non-blocking API.
- Transparently handles reads and writes to/from memory on both host and device.
import cupy import kvikio def main(path): a = cupy.arange(100) f = kvikio.CuFile(path, "w") # Write whole array to file f.write(a) f.close() b = cupy.empty_like(a) f = kvikio.CuFile(path, "r") # Read whole array from file f.read(b) assert all(a == b) f.close() # Use contexmanager c = cupy.empty_like(a) with kvikio.CuFile(path, "r") as f: f.read(c) assert all(a == c) # Non-blocking read d = cupy.empty_like(a) with kvikio.CuFile(path, "r") as f: future1 = f.pread(d[:50]) future2 = f.pread(d[50:], file_offset=d[:50].nbytes) # Note: must wait for futures before exiting block # at which point the file is closed. future1.get() # Wait for first read future2.get() # Wait for second read assert all(a == d) if __name__ == "__main__": main("/tmp/kvikio-hello-world-file")
#include <cstddef> #include <future> #include <cuda_runtime.h> #include <kvikio/file_handle.hpp> int main() { // Create two arrays `a` and `b` constexpr std::size_t size = 100; void *a = nullptr; void *b = nullptr; cudaMalloc(&a, size); cudaMalloc(&b, size); // Write `a` to file kvikio::FileHandle fw("test-file", "w"); std::size_t written = fw.write(a, size); fw.close(); // Read file into `b` kvikio::FileHandle fr("test-file", "r"); std::size_t read = fr.read(b, size); fr.close(); // Read file into `b` in parallel using 16 threads kvikio::default_thread_pool::reset(16); { // FileHandles have RAII semantics kvikio::FileHandle f("test-file", "r"); std::future<std::size_t> future = f.pread(b_dev, sizeof(a), 0); // Non-blocking std::size_t read = future.get(); // Blocking // Notice, `f` closes automatically on destruction. } }