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    <p>Unless your program has very few functions and hardly ever calls a system function or I/O, profilers that sample the program counter won't tell you much, as you're discovering. In fact, the well-known profiler <em>gprof</em> was created specifically to try to address the uselessness of self-time-only profiling (not that it succeeded).</p> <p>What actually works is something that samples the <em>call stack</em> (thereby finding out where the calls are coming from), on <em>wall-clock</em> time (thereby including I/O time), and report <em>by line or by instruction</em> (thereby pinpointing the function calls that you should investigate, not just the functions they live in).</p> <p>Furthermore, the statistic you should look for is <em>percent of time on stack</em>, not number of calls, not average inclusive function time. <em>Especially not "self time".</em> If a call instruction (or a non-call instruction) is on the stack 38% of the time, then if you could get rid of it, how much would you save? <strong>38%!</strong> Pretty simple, no?</p> <p>An example of such a profiler is <a href="http://www.rotateright.com/" rel="nofollow noreferrer">Zoom</a>.</p> <p>There are <a href="https://stackoverflow.com/questions/1777556/alternatives-to-gprof/1779343#1779343">more issues to be understood</a> on this subject.</p> <p>Added: @caf got me hunting for the <code>perf</code> info, and since you included the command-line argument <code>-g</code> it does collect stack samples. Then you can get a <a href="http://lwn.net/Articles/340010/" rel="nofollow noreferrer">call-tree</a> report. Then if you make sure you're sampling on wall-clock time (so you get wait time as well as cpu time) then you've got <em>almost</em> what you need.</p>
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    1. CO`perf` *does* sample the call stack. It's just that the report the OP is generating is only showing the leaves.
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    2. CO@caf: I just [searched again](http://lwn.net/Articles/340010/) and got that if you include the `-g` option it collects stack samples. I assume it can do it on wall-clock time. The OP should find that helpful. Now all that remains is the by-line report.
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    3. CO@caf: how do I display the whole tree then?
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