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

Subject: Re: enhanced seq record
From: Luedeke Andreas <Andreas.Luedeke@psi.ch>
To: Benjamin Franksen <benjamin.franksen@bessy.de>
Cc: core-talk@aps.anl.gov, tech-talk@aps.anl.gov
Date: Mon, 30 Jan 2006 10:05:15 +0100
Benjamin Franksen wrote:

On Saturday 28 January 2006 00:52, Chestnut, Ronald P. wrote:


If you do change the seq record (or make a new one), can you please
change the behaviour for a "0" delay? Now a new thread is started for
each (DOL/LNK) pair. If the delay is zero, can you "just do it" in
the same thread? We found that for some big "explosions" (nested
SEQs) the task switching dominates the processing time.


[...]

However, it /does/ request a callback for each group, regardless whether
the delay is zero or not, and this can indeed cause unnecessary context switches. So, yes, I will change this. Adjacent link groups with zero delay will be processed in a synchronous manner i.e. w/o requesting a callback.


Thanks for the hint.

If I remember correctly the "seq" record is 100% asynchronous.
If you specify delays of "0", all DOLn links are supposed to be read at the same time.
How do you want to do this without a callback?
(You need it to place the value into DOn when it's received and then write it to LNKn.)


But of course it would be sometimes useful to have a synchronous process chain,
where the next link is processed after the the previous one completed and then the delay elapsed.


Regards
Andreas


References:
Re: enhanced seq record Benjamin Franksen

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