This white paper summarizes findings and recommends best practices to tune the different layers of an application’s environment for similar latency-sensitive workloads. By latency-sensitive, VMware means workloads that are looking at optimizing for a few microseconds to a few tens of microseconds end-to-end latencies; they don’t mean workloads in the hundreds of microseconds to tens of milliseconds end-to-end-latencies. In fact, many of the recommendations in this paper that can help with the microsecond level latency can actually end up hurting the performance of applications that are tolerant of higher latency.
- BIOS Settings
- NUMA
- Choice of Guest OS
- Physical NIC Settings
- Virtual NIC Settings
- VM Settings
- Polling Versus Interrupts
- Guest OS Tips and Tricks
VMware also has investigated the performance of two latency micro-benchmarks, one for Infiniband devices and another for networking devices, in VM DirectPath I/O (pass-through) mode, which bypasses most of the virtualization stack except the path for delivering interrupts from the underlying physical devices to the guest OS. Applying the recommendations reduced latency and therefore increased the score of these latency micro-benchmarks in a virtualized environment, bringing it closer to bare metal performance.
Best Practices for Performance Tuning of Latency-Sensitive Workloads in vSphere VMs
