Question

I am trying to determine the impact of context switching on my Java thread. Therefore I would have to know first “how many times has it been preempted?” and second, if possible, “how long was my thread suspended from execution?”. I would doubt very much that this can be done from Java, but hey! the fun things is to do the impossible, right? 🙂 Even If I have to recompile the VM or to use some kind of LINUX tool or hack I would be happy. So now that we know that can’t be done, let’s do it. 🙂

EDIT: Come on people. The other question was priority related. I guess you just enjoy easy and boring questions. The question is clear and valid.

Answer 1

If you can identify the Linux TID (thread ID) for the Java thread you’re interested in (assuming your JVM maps Java threads onto Linux threads) then the pseudo-file /proc/<tid>/status contains many statistics, including voluntary_ctxt_switches and nonvoluntary_ctxt_switches.