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Entry  19 Feb 2025, Lukas Gerritzen, Bug Report, Default write cache size for new equipments breaks compatibility with older equipments 
    Reply  24 Feb 2025, Stefan Ritt, Bug Report, Default write cache size for new equipments breaks compatibility with older equipments 
       Reply  20 Mar 2025, Konstantin Olchanski, Bug Report, Default write cache size for new equipments breaks compatibility with older equipments 
          Reply  20 Mar 2025, Konstantin Olchanski, Bug Report, Default write cache size for new equipments breaks compatibility with older equipments 
             Reply  20 Mar 2025, Konstantin Olchanski, Bug Report, Default write cache size for new equipments breaks compatibility with older equipments 
                Reply  20 Mar 2025, Konstantin Olchanski, Bug Report, Default write cache size for new equipments breaks compatibility with older equipments 
                Reply  21 Mar 2025, Stefan Ritt, Bug Report, Default write cache size for new equipments breaks compatibility with older equipments 
                   Reply  25 Mar 2025, Konstantin Olchanski, Bug Report, Default write cache size for new equipments breaks compatibility with older equipments 
Message ID: 3004     Entry time: 25 Mar 2025     In reply to: 2979
Author: Konstantin Olchanski 
Topic: Bug Report 
Subject: Default write cache size for new equipments breaks compatibility with older equipments 
>  > All this is kind of reasonable, as only two settings of write cache size are useful: 0 to 
> > disable it, and 10 Mbytes to limit semaphore locking rate to reasonable value for all event 
> > rate and size values practical on current computers.
> 
> Indeed KO is correct that only 0 and 10MB make sense, and we cannot mix it. Having the cache setting in the equipment table is 
> cumbersome. If you have 10 slow control equipment (cache size zero), you need to add many zeros at the end of 10 equipment 
> definitions in the frontend. 
> 
> I would rather implement a function or variable similar to fEqConfWriteCacheSize in the tmfe framework also in the mfe.cxx 
> framework, then we need only to add one line llike
> 
> gEqConfWriteCacheSize = 0;
> 
> in the frontend.cxx file and this will be used for all equipments of that frontend. If nobody complains, I will do that in April when I'm 
> back from Japan.

Cache size is per-buffer. If different equipments write into different event buffers, should be possible to set different cache sizes.

Perhaps have:

set_write_cache_size("SYSTEM", 0);
set_write_cache_size("BUF1", bigsize);

with an internal std::map<std::string,size_t>; for write cache size for each named buffer

K.O.
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