Re: Why does the extcap stuff take so long to start up?

[Dario Lombardo <dario.lombardo.ml () gmail com>]

The problem is only when compiling with autotools. With cmake the bin
extcap dir is clean and it doesn't affect startup time. Btw the check you
added is wise and should be done anyway in case unwanted artifacts are
there. The problem with extcaps is that androiddump is the only tool that
enumerates interfaces at start time. Others have static interfaces and
start very quickly. Me, Michal and others have discussed a lot on this
topic but we didn't find a final answer. At the moment there is a timeout
of 4s to allow androiddump to connect to ADB. If ADB is not running, we
wait until the timeout, and it's pretty annoying if you don't have adb and
will never have, imho.

A faster solution would be to check if the process adb is running and if
it's not, just skip the attempt. But we didn't find a suitable way to do so
on unix & windows. A possible solution could be to run this check on
systems that support the choosen method (like kill described here
http://stackoverflow.com/questions/6898337/determine-programmatically-if-a-program-is-running),
and skip it on windows, leaving the things as they are right now. Michal
what do you think?

On Mon, Mar 27, 2017 at 10:14 PM, Guy Harris <guy () alum mit edu> wrote:

> On Mar 26, 2017, at 11:30 PM, Michał Łabędzki <
> michal.tomasz.labedzki () gmail com> wrote:
>
> > Could you check if any of extcap binaries generates that delay?
>
> A lot of the delay comes from extcap *non*-binaries; the code that scans
> the extcap directory tried running *everything* it finds there, except for
> "." and "..", and, if you're running from the build directory, that means
> executing somewhat heavyweight {fork/vfork}-exec calls on a bunch of source
> files, object files, .deps directories, Makefiles, etc..
>
> bd3196b094ae46fa4396edbb406d68056cba6974 fixed that.
>
> Currently, with that fix, I get results like
>
> $ time ./tshark -r /tmp/nothing.pcap
>
> real    0m1.407s
> user    0m0.312s
> sys     0m0.676s
>
> with the extcap directory in place and results like
>
> $ time ./tshark -r /tmp/nothing.pcap
>
> real    0m0.334s
> user    0m0.182s
> sys     0m0.146s
>
> with the extcap directory moved out of the way, so the extcap executables
> are taking some time to run, but it's better than wasting time trying to
> run androiddump.c or Makefile.am.
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