The Performance Of A No-Copy API For Communication

We present a so-called no-copy Application Programming Interface (API) for communication. The interface avoids copying when data is transferred between the application and operating system kernel address spaces. The API is an extension to the socket interface for SunOS, and has been implemented on Sun SPARCstations equipped with Fore Systems ATM adapters. Throughput for the no-copy API is 85 Mbit/s for 8K UDP messages, to be compared to 57 Mbit/s for the regular API on the SPARCstation 2. Processing times through the TCP and UDP stacks are reduced by up to 30% for the SPARCstation 2 and by more than 50% for the SPARCstation 10.