[FieldTrip] delays on computing server

[Schoffelen, J.M. (Jan Mathijs)]

Hoi Roy,

The compute server sounds like an interesting use case. Are you using mathworks’ parallel server functionality for this? We have recently started exploring and documenting a bit the possibilities for using matlab’s parallel processing tools in FieldTrip, in collaboration with Mathworks and Vortech<https://urldefense.com/v3/__https://www.vortech.nl__;!!HJOPV4FYYWzcc1jazlU!-ld--Q_DRiwfhl22L94A2cbFEL4iDJa8LCyV2Ls36yIpVS1PQUwCeJr2qhHPVca3kmUF9i5SbYThi2-qSoZrd5IhA5p_cPqJGO001A$ > . Please see https://urldefense.com/v3/__https://www.fieldtriptoolbox.org/tutorial/distributedcomputing_parfor/__;!!HJOPV4FYYWzcc1jazlU!-ld--Q_DRiwfhl22L94A2cbFEL4iDJa8LCyV2Ls36yIpVS1PQUwCeJr2qhHPVca3kmUF9i5SbYThi2-qSoZrd5IhA5p_cPp0n-bR4w$  for some initial documentation. We would be very happy to receive insights/use cases/best practices/tips ’n tricks from the FieldTrip users, to be documented on the website as well.

Now, regarding to your question, I don’t have a pasklaar answer, but I would start with profiling the execution of the slow functions: this will give you an indication which lines take most time to execute, so that you can tweak (if possible) the ‘overhead’-options. Typing ‘help profile’ and ‘help profview’ should get you started.

Met groet,
Jan-Mathijs


On 9 Mar 2023, at 15:07, Roy Cox via fieldtrip <fieldtrip at science.ru.nl<mailto:fieldtrip at science.ru.nl>> wrote:

hello all,

We recently started batching EEG analyses, involving FieldTrip code, on a computing server (essentially a big Windows workstation).

Mostly great, but I've noticed that there are sometimes lengthy delays (tens of seconds) when executing a FieldTrip command.

Possibly related, I sometimes see warnings like these:

Warning: could not send tracker information for "startup"

It's all very poorly reproducible: the exact same script operating on the same recording sometimes runs fast and sometimes takes forever.

One reason I can think of is that this has something to do with FieldTrip trying to send some information to its developers for tracking purposes, but perhaps this isn't suitable for a computing server running many jobs in parallel.

Supposing that's indeed the issue: is there a way to disable any and all communication attempts by FieldTrip to the outside world? I looked at ft_defaults but not sure which options to choose.

And any other suggestions as to what might be going on are welcome of course.

Best,
Roy
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