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<== Date ==> <== Thread ==>

Subject: RE: JCA problems and questions
From: "Chu, Paul" <[email protected]>
To: Till Straumann <[email protected]>
Cc: "'Matej Sekoranja'" <[email protected]>, "[email protected]" <[email protected]>
Date: Tue, 23 Oct 2012 23:54:56 +0000
Hi Till,

I haven't checked the latest source code but what I said was the way I coded.  I don't know if Matej had changed the behavior or not.  The JCA being used at SLAC is behaving this way as Jingchen verified.  I only did for jca, not caj, though.  Matej probably added the caj one and it's better to make sure they both (jca and caj) are consistent.

We ran into trouble by specifying a very large max array size with EPICS environment variable which slowed down some Java apps.  That's why the order 1, 2, 3, 4 is there -- it can give users the maximum flexibility and with best consistent (for Java and non-Java apps) CA parameter settings.

Paul

-----Original Message-----
From: Till Straumann [mailto:[email protected]] 
Sent: Tuesday, October 23, 2012 7:05 PM
To: Chu, Paul
Cc: Mark Rivers; 'Matej Sekoranja'; [email protected]
Subject: Re: JCA problems and questions

Is that really true? The way I recall it (but it has been a while I dived into that subject) is

if use_env property is true then
   1.
else
   2.
   3.
   4.
endif

- T.

On 10/23/2012 11:01 PM, Chu, Paul wrote:
> When I first implemented this feature at SLAC, I believe JCA or CAJ took the following override order (higher number overrides lower ones, e.g. 2 overrides 1):
>
> 1. EPICS environment variables
> 2. System level JCALibrary.properties (in system JRE or JDK's lib 
> folder) 3. User level JCALibrary.properties (e.g. in user's 
> ~/.JCALibrary for Linux) 4. Command line -D option
>
> Paul
>
>> -----Original Message-----
>> From: [email protected] [mailto:tech-talk- 
>> [email protected]] On Behalf Of Mark Rivers
>> Sent: Tuesday, October 23, 2012 4:37 PM
>> To: 'Matej Sekoranja'; [email protected]
>> Subject: RE: JCA problems and questions
>>
>> Hi Matej,
>>
>> Thanks for the reply.
>>
>> Lewis also pointed out the new feature of caj.use_env to have CAJ use 
>> the traditional EPICS environment variables.  I am now using that in 
>> the areaDetector ImageJ plugin.  However, I have a couple of questions:
>>
>> - What is the order of obtaining values from a JCALibrary.properties 
>> file versus the EPICS environment variables?
>>
>> - Is the new caj.use_env documented anywhere except the single line 
>> in the change notes?
>>
>> Thanks,
>> Mark
>>
>>
>> From: [email protected] [mailto:tech-talk- 
>> [email protected]] On Behalf Of Matej Sekoranja
>> Sent: Tuesday, October 23, 2012 3:33 PM
>> To: [email protected]
>> Subject: Re: JCA problems and questions
>>
>> Hi,
>>
>> Rok Sabjan notified me about this thread. Thanks to Lewis for replies.
>>
>> The old send buffer algorithm was to initialize the send buffer size 
>> to max_array_bytes and automatically resize on demand (there is one 
>> send buffer per TCP connection). Not something one would dare to use 
>> on a server, however very convenient on the client side.
>>
>> However, if a client has a lot of connections there is a lot of 
>> memory required when max_array_bytes is large (e.g. 100 connection * 10MB = 1GB!).
>> Current algorithm starts with an initial size of 1k that can be 
>> automatically resized up to max_array_bytes.
>> This also mimics C++ CA algorithm (that has also evolved over the years).
>>
>> Cheers,
>> Matej
>



References:
Re: JCA problems and questions Matej Sekoranja
RE: JCA problems and questions Mark Rivers
RE: JCA problems and questions Chu, Paul
Re: JCA problems and questions Till Straumann

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