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Entry  01 May 2020, Joseph McKenna, Forum, Taking MIDAS beyond 64 clients 
    Reply  01 May 2020, Stefan Ritt, Forum, Taking MIDAS beyond 64 clients 
       Reply  01 May 2020, Pierre Gorel, Forum, Taking MIDAS beyond 64 clients 
          Reply  02 May 2020, Stefan Ritt, Forum, Taking MIDAS beyond 64 clients 
             Reply  02 May 2020, Joseph McKenna, Forum, Taking MIDAS beyond 64 clients 
                Reply  02 May 2020, Stefan Ritt, Forum, Taking MIDAS beyond 64 clients 
    Reply  02 May 2020, Konstantin Olchanski, Forum, Taking MIDAS beyond 64 clients 
       Reply  02 May 2020, Konstantin Olchanski, Forum, Taking MIDAS beyond 64 clients 
          Reply  02 May 2020, Konstantin Olchanski, Forum, Taking MIDAS beyond 64 clients 
Message ID: 1899     Entry time: 02 May 2020     In reply to: 1898
Author: Konstantin Olchanski 
Topic: Forum 
Subject: Taking MIDAS beyond 64 clients 
> > > 
> > > Does the community here have strong opinions about increasing the 
> > > MAX_CLIENTS and MAX_RPC_CONNECTION limits? 
> > > Am I looking at this problem in a naive way?
> > > 

The issue is: how to organize an experiment? how many frontends should I have?

There are two extremes:

- collect all data in 1 frontend (and today with c++ threads and c++ ring buffers, this is trivial)
- instantiate 1 frontend for each data source. (for example, ALPHA-g detector has 8 ADCs, 64 PWBs plus some
small fish. No that's wrong. Each ADC looks like 48 individual data sources, each PWB looks like 4 data sources,
so this would be 8*48+4*64=640 data sources, could be 640 frontends easily, plus small fish).

Which way is best? Every experiment is different, but consider simple things:

640 frontends writing into 1 event buffer will probably cause large contention for the event buffer lock. bad.
640 frontends running on a 4 core CPU will probably cause unhappiness in the OS. bad.
starting and stopping 640 frontends requires some scripting, monitoring that they all still run, etc. extra work. bad.
640 frontends on the midas status page? your cell phone web browser will explode. bad.

What I am saying is - arbitrary limits are good for you. Make you think about what is going on before throwing 
resources at the problem.

K.O.
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