Am 08.07.2016 um 01:03 schrieb Stepan Zakharov: > Hello, > If I remember correct, callgrind takes x30 overhead in general (when I > was running it). Usually , I had to run it on small tasks that won't > take more then a few minutes, so this was not a bother to me. > > But right now I am wonering if I can measure the entire life-span of > critical stages in our application. Usually, it takes up to 20 hours to > perform a load test. And I would like to measure that period. For > callgrind it means to run 20x30=600hrs. Which is 25 days. Is it really > possible to run and record for such a long time? I heard the Counters in > CallGrind are 64-bit so this part should not be the problem, but what > I'm worrying about is the RAM overhead.
Callgrind allocates a bunch of 64-bit counters for every instruction in the binary which gets executed at least once, as well as counters for jump/call arcs happening among blocks of instructions in your code. Both is bound by the codes size/algorithms executed, but it does not matter if code/jumps are executed only once or multiple times. That is, if all code paths of your program get already executed in the first few minutes, the memory requirement of callgrind should not increase afterwards. > It will kinda need to store all > the upcoming dump in memory, isn't it? How much big will it be? And if > so, will the CallgrindAnnotate or graphical tool (forgot the name) > accept to proccess such a big dump? Same applies here: there should be no problem. > So, basically, these are my questions. Will be very grateful if you > could enhance my knowledge about the capabilities of the tool. Perhaps interesting for you is the "fast-forward" mode of callgrind which allows to dynamically switching on/off profiling to skip program phases with the benefit of reducing the slow-down to around 2x (same as Valgrind's "none" tool) See callgrinds option "--instr-atstart", "callgrind-control --i on/off" and the macros CALLGRIND_START/STOP_INSTRUMENTATION. And I would dump the profile already while callgrind is running, as Philippe suggested. Josef > Best, > Stepan ------------------------------------------------------------------------------ What NetFlow Analyzer can do for you? Monitors network bandwidth and traffic patterns at an interface-level. Reveals which users, apps, and protocols are consuming the most bandwidth. Provides multi-vendor support for NetFlow, J-Flow, sFlow and other flows. Make informed decisions using capacity planning reports.http://sdm.link/zohodev2dev _______________________________________________ Valgrind-users mailing list Valgrind-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/valgrind-users
