Visualizing the flow
Multicore systems have led to processes – well, threads really (both user - and kernel-space ones) – executing concurrently on different processors. This is useful for gaining higher throughput and thus performance, but it also causes synchronization headaches when they work with shared writable data (we shall deal in depth with the really important topic of kernel synchronization in this book’s last two chapters).
So, for example, on a hardware platform with, say, six processor cores, we can expect processes (threads) to execute in parallel on them; this is nothing new. Is there a way, though, to actually see which processes or threads are executing on which CPU core – that is, a way to visualize a processor timeline? It turns out there are indeed a few ways to do so. In the following sections, we will look at a couple of interesting ways: with the gnome-system-monitor GUI program, perf, as well as other possibilities.
