Re: [Caml-list] Profiling ocaml with lwt

[Malcolm Matalka <mmatalka@gmail.com>]

Török Edwin <edwin+ml-ocaml@etorok.net> writes:

> On 03/09/2016 11:57, Kasper Janssens wrote:
>> Den 9 mar 2016 9:54 fm skrev "Kasper Janssens" <Kasper.Janssens@hgst.com <mailto: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.
>
> Is that communication done over a TCP/UDP socket?
> You could use wireshark and see if you spot anything (e.g. too many SSL handshakes -> application would benefit from persistent connections, etc.)
>
> Depending on the complexity of your application you may try to use a branch of Lwt that reports more tracing information,
> although this would likely require manual annotations to produce useful output:
> http://roscidus.com/blog/blog/2014/10/27/visualising-an-asynchronous-monad/
>
> I usually just wrap+log calls and use strace though, as already
> mentioned in this thread.

And if you're on FreeBSD or OS X or Solaris you can use dtrace.

>
> Best regards,
> -- 
> Edwin Török | Co-founder and Lead Developer
>
> Skylable open-source object storage: reliable, fast, secure
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