Shoot first and stop the OS noise Dealing with microsecond latency requirements

Latency requirements for Linux software can be ex-treme. One example is the financial industry: Who-ever can create an order first in response to a change in market conditions has an advantage. In the high performance computing area a huge number of calcu-lations must occur consistently with low latencies on large number of processors in order to make it possi-ble for rendezvous to occur with sufficient frequency. Games are another case where low latency is important. In games it is a matter of survival. Whoever shoots first will win. An operating system causes some interference with user space processing through scheduling, interrupts, timers, and other events. The application code sees execution being delayed for no discernible reason and a variance in execution time due to cache pollution by the operat-ing system. Low latency applications are impacted in a significant way by OS noise. We will investigate issues in software and hardware for low latency applications and show how the OS noise has been increasing in recent kernel versions.