On registering values for use in C

On registering values for use in C

[Nathaniel Gray]

I have a question about registering values for use in C.  I've read
that registering lots of values can have a bad effect on GC
performance, but what about registering "large" values?  For example,
is registering a record with 20 fields just as bad as registering 10
records with 2 fields each?

Thanks,
-n8

-- 
>>>-- Nathaniel Gray -- Caltech Computer Science ------>
>>>-- Mojave Project -- http://mojave.cs.caltech.edu -->

Re: [Caml-list] On registering values for use in C

[Robert Roessler]

Nathaniel Gray wrote:
> I have a question about registering values for use in C.  I've read
> that registering lots of values can have a bad effect on GC
> performance, but what about registering "large" values?  For example,
> is registering a record with 20 fields just as bad as registering 10
> records with 2 fields each?

Having implemented "generational" GCs, I can make a generic comment on 
this (without consulting the OCaml sources): as each one of the items 
you register represents a "root" (for our purposes, a tree of items 
which *may* or *may not* not be pointed to by any other item), there 
is a certain amount of per-root overhead that gets amortized over the 
items "marked" (or copied or whatever) during a GC.  This being the 
case, it is likely that your case of "a record with 20 fields" will be 
"less bad" than your case of "10 records with 2 fields each".

Robert Roessler
roessler@rftp.com
http://www.rftp.com