[Gcl-devel] Maxmimum memory allocations

[Camm Maguire]

Greetings!

"Warren A. Hunt Jr." <address@hidden> writes:

> Hi Camm,
> 
> Bob will be out of the office most of today, so I went ahead and
> re-ran the troublesome test Bob was running.  It now appears to
> complete fine.  I'm sure Bob will very soon rerun all of his tests.
> 

Great!

> I am interested in trying the twc-GCL on our computational biology
> codes, but I would first like to build a large-memory image.  Can you
> point me to a place where I could get a copy of GCL with two-word CONS
> elements?  Also, did you determine whether making MAXPAGES 262144
> causes any problems?  I ask because from our discussions about the
> maximum number of available pages would really be something closer to
> the number of pages that will fit in 800 megabytes.
> 

Yes, if you could copy the tree (with cp -a) from
/u/camm/gcl-2.6.6rwc, make clean, configure and rebuild, that would be
great.  The build at this location is a debugging build for you and
Bob if needed.  I would multiply the MAXPAGES abouve by 7/8 or
somewhat less.  I hope to make this determination more robust soon.

There is a -Ttext option to the linker which should allow us to
reclaim the 128M and start at 0 -- unfortunately, it does not work out
of the box -- perhaps a linker script is needed.  I also ran across a
kernel configuration option the other day (2.6.11) -- you can specify
that your system has more than 1Gb memory, and I bet (untested) that
this will move the shared library start.  It would be great if you had
an interested student and a spare machine to try it out, only if time
permits of course.  If you do get 2.7Gb working memory on 32bit, this
of course is equivalent to 5.4Gb on 64bit, so I don't think the option
is worthless.  Indeed, kernel 2.6.11 appears to be able to address up
to 64Gb on a 32bit machine.

Take care,

> Cheers,
> 
> Warren
> 
> 
> 

-- 
Camm Maguire                                            address@hidden
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