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Re: MLton on PowerPC: voltaire's Christmas wish?



On Wed, Dec 22, 2004 at 03:59:55PM +0100, Wesley W. Terpstra wrote:
> On Wed, Dec 22, 2004 at 09:42:01AM +0100, Ingo Juergensmann wrote:
> > Well, having more RAM is always nice, but IMHO there's something wrong with
> > MLton when it needs that much RAM for building. 
> It's a whole-program optimizing compiler...
> That means it analyzes all of the source code at once.
> When compiling a large project (MLton is ~145k lines) it needs memory.
> I agree that this is unfortunate; however, if you check out the runtime
> performance of MLton compiled applications, you'll see the advantages. =)

Well, if it's an advantage if you can't use it because you can't compile it,
is argueable, I think... ;)  

> > buildd=> select distinct ram, count(*) from status group by ram;
> >  ram  | count |  arch
> > ------+-------+---------
> >    48 |     1 | m68k
> >    64 |     6 | arm mipsel m68k mips
> >    80 |     1 | m68k
> >    90 |     1 | mips
> >    96 |     3 | mips m68k
> >   128 |    11 | arm mips m68k
> >   132 |     1 | m68k
> >   136 |     1 | m68k
> >   144 |     2 | m68k
> >   256 |     4 | m68k mips s390
> >   320 |     1 | powerpc
> >   512 |     6 | amd64 sparc alpha
> >   768 |     1 | hppa
> >  1024 |     2 | alpha hppa
> >  1536 |     1 | amd64
> >  2048 |     1 | sparc
> >  4096 |     2 | alpha ia64
> Thanks a lot for this list! I've been trying to find it for a month.
> Where did you get this?

It's the database used on buildd.net. Not all of those are "official"
buildds, but it reflects the buildds used for non-free, backports and
experimentel as well. 

> > As you can see, many buildds are low on RAM. How do you want to solve that?
> I am not planning on porting MLton to any platform with less memory.
> PowerPC is the exception; lots of people use it and it can handle the RAM.
> I've already done hppa and sparc. amd64, ia64, and alpha need some 64bit
> cleanups, so I was planning on doing that after the easier 32bit ports.

Maybe you want to get the other archs listed in N-F-U. 

> > but maybe it's possible for MLton as well to lower the RAM requirements?
> > Of course you would need to know where and why the RAM is needed... 
> Well, I'm in contact with the developers of MLton, and they seem to think
> this is an inherent disadvantage of whole-program optimization. Their (valid
> imo) argument is that requiring a powerful build machine is better than
> requiring a powerful machine to run the resulting binary.

Sure, but I wonder where to draw the line? Maybe next week another program
want to have 2G of RAM or 1 TB of disk space to build... ;)

-- 
Ciao...              // 
      Ingo         \X/

Please note that year 2004 is coming to an end and 
the year 2005 is near  -  even in my mail address!



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