Thanks to simultaneous multithreading on AMD and Hyperthreading on Intel, modern processors can handle two threads per physical core. Under different workloads, this helps improve performance, but it's not always easy to identify which threads are the “strongest” and adjust process affinity accordingly. This is where the app ThreadRacer, from the same developer as Process Lasso and CPUBalance, comes in.
The latest multithreading news revolves almost exclusively around security. Spectre and Meltdown left the industry in a frenzy, and manufacturers are doing everything they can to reduce their impact, but we're starting to see a certain intention to abandon SMT/HT and offer only real cores. Without going too far, two of Intel's last three processors (the Core i5-9600k and the Core i7-9700k) do not have Hyperthreading, and AMD has shown that it doesn't have major issues placing 16 or 32 cores on our desktops. However, that doesn't mean logical threads are useless. Quite the contrary: as users, we should know which threads are strongest on our chips, but we need the help of an external tool.
ThreadRacer: A Benchmark for Each CPU Thread
That combination of identification and benchmarking is handled by ThreadRacer. If the name sounds familiar, it's because we're dealing with a tool created by the same developer that offers us Process Lasso, and its younger brother CPUBalance. The idea behind ThreadRacer is to select the available threads, let the benchmark run, and closely examine their performance. Each thread presents its performance as a percentage of the fastest-running thread. During my test, I noticed that the first thread is a bit slower, while the rest stay fairly even.
Why is this important? There is still a huge number of applications that can only take advantage of a single thread in our system, ignoring the rest. If you know which one tends to be the strongest, with a simple affinity adjustment you can assign that application to that thread, getting maximum performance. I admit that ThreadRacer requires a bit of experimentation, and it only lets us control the first eight available threads, but if you want to squeeze the most out of your processor, it's not a bad tool to have around.
