[Ltrace-devel] ltrace overhead

yogender nerella ynerella at gmail.com
Wed Apr 8 17:32:01 UTC 2015


Thanks Petr.

I have googled a lot and dont really find any great c++ profiling tools (
free), do you recommend any?

ltrace suggests most of our application is spent on "memcmp", but by
looking at our code, we don't see that as a possibility.

Thanks,
Yogi


On Fri, Mar 27, 2015 at 2:03 AM, Petr Machata <pmachata at redhat.com> wrote:

> yogender nerella <ynerella at gmail.com> writes:
>
> > I am profiling a large application involving oracle database libraries.
> >
> > Without any tracing my program completes in 2 to 3 minutes, but with
> ltrace
> > it is taking over 2 to 3 hours.
>
> ltrace is not a great tool for profiling.  Every event implies a context
> switch (that's the design of the underlying kernel ptrace interface that
> ltrace is using).  That's where the overhead comes from.
>
> > All our code is in the binary, and oracle libraries are dynamically
> linked.
> >
> > What are the command line options, to just profile my application?
> > What are the command line options to just profile oracle libraries?
>
> Check out -e.  That's used for selecting which library calls from which
> libraries you want displayed.
>
> Thanks,
> Petr
>
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