Generally I wrap external calls in something that gets that gets the wall
time of an external service call and logs it somewhere.
Den 9 mar 2016 9:54 fm skrev "Kasper Janssens" <Kasper.Janssens@hgst.com>:

> Hello,
>
>
> I’m trying to profile an ocaml application that has a performance
> degradation of about 20 %, with quite some code changes between both
> versions. I tried attaching perf and gprof to it, but to no real avail.
> Sure, there are slight differences in the running time of functions in the
> gprof result, but nothing whatsoever that seems to explain that kind of
> delay. Perf doesn’t seem to indicate a problem neither.
>
>
> The thing is, I think it’s a delay in one of the servers that the
> application communicates with. The communication to those servers is done
> asynchronously, through lwt (epoll). I suspect that is the reason why
> delays in that communication don’t show up in the gprof result, but I’m not
> really sure.
>
>
> Does anybody know of a way to profile lwt applications in a way that these
> kinds of delays might show up so I know which backend system I have to
> focus on?
>
>
> Kasper
>
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