Man, am I confused! I have a relatively straightforward problem: I am trying to track down
latency and jitter problems in a realtime media stream generating application. How do I
decide what tool to use? Oprofile? Ftrace? Perf events? SystemTap? LTTng?
I've tried oprofile briefly, and it seemed mostly irrelevant for my problems. I can't find any
clear descriptions of what ftrace and perf events actually are, so that I could figure out
whether I should bother with them. I've been fairly happy with systemtap so far -- it is at least
straightforward to dive into and start generating customized traces that at least startto
address what I'm interested in. Each further step seems to involve more and more groveling
about in the kernel sources, but at least I can understand the path ahead and predict what's
going to be possible. (I have a fairly generic problem -- I want to measure the jitter between
context switches of my realtime threads and then diagnose the reasons for that jitter by
reporting what the CPUs were up to when I wasn't running.)
But now I see that SystemTap is viewed as the bastard stepchild, and I wonder if my
investment into learning to use SystemTap was an expensive mistake. Any guidance on
choosing an appropriate tool for unfortunates like me?