DATA STORAGE SYSTEM WITH PERFORMANCE-BASED DISTRIBUTION OF I/O REQUESTS TO PROCESSING CORES

A method of assigning I/O requests to CPU cores of a data storage system includes, in a first operating mode, assigning I/O requests to CPU cores based on port affinity while maintaining a current I/O completion count, and regularly performing a first test-and-switch operation that includes (i) for a sample interval, temporarily assigning the I/O requests to the CPU cores based on core availability while obtaining a sample I/O completion count, (ii) comparing the first sample I/O completion count to the current I/O completion count, and (iii) based on the sample I/O completion count being greater than the current I/O completion count, switching to a second operating mode. In the second operating mode, I/O requests are assigned to the CPU cores based on core availability, and similar operations are performed for periodically testing whether to switch to the first operating mode.