[FLASH-USERS] Quick maxblocks question

Klaus Weide klaus at flash.uchicago.edu
Thu Jul 12 13:10:32 EDT 2018


On Thu, 12 Jul 2018, Nicholas Omahen wrote:

> Maxblocks decides the total blocks that can be allotted per processor.
> 
> Say you have 10 processors, and 10,000 total blocks is the max that will be
> generated; you'd want -maxblocks=1000 to distribute them evenly. 

In practice you'd need some more, say -maxblocks=1100, for temporary 
internal use by the Grid unit during refinement changes.

> However,
> if you made maxblocks much higher that necessary (say -maxblocks=10,000),
> is there any penalty in performance? Would the blocks be distributed
> amongst processors evenly?

In my experience there is no significant impact on performance from 
maxblocks being unnecessarily large. Others's experience may vary.

The distribution does not depend on maxblocks - as long as maxblocks is 
large enough, the number of blocks that get assigned to processor i 
does not depend on maxblocks.

Klaus



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