How to profile my C++ application on linux

Question

I would like to profile my c++ application on linux. I would like to find out how much time my application spent on CPU processing vs time spent on block by IO/being idle.

Answer 1

google-perf-tools - much faster alternative to callgrind (and it can generate output with the same format as callgrind, so you can use KCacheGrind).

Answer 2

LTTng is a good tool to use for full system profiling.

Answer 3

callgrind is a very good tool but I found OProfile to me more 'complete'. Also, it is the only one that lets you specify module and/or kernel source to allow deeper insight into your bottlenecks. The output is supposed to be able to interface with KCacheGrind but I had trouble with that so I used Gprof2Dot instead. You can export your callgraph to a .png.

Edit:

OProfile looks at the overall system so the process will just be:

[setup oprofile]

opcontrol --init
opcontorl --vmlinux=/path/to/vmlinux     (or --no-vmlinux)
opcontrol --start

[run your app here]

opcontrol --stop   (or opcontrol --shutdown [man for difference]

then to start looking at the results look at the man page on opreport