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 Western Digital Corporation (and its subsidiaries) E-mail Confidentiality Notice & Disclaimer: This e-mail and any files transmitted with it may contain confidential or legally privileged information of WDC and/or its affiliates, and are intended solely for the use of the individual or entity to which they are addressed. If you are not the intended recipient, any disclosure, copying, distribution or any action taken or omitted to be taken in reliance on it, is prohibited. If you have received this e-mail in error, please notify the sender immediately and delete the e-mail in its entirety from your system.