[racket] DrRacket never uses more than 1 GB?

Although it makes sense that a 32-bit pointer can address only 4 GB
(virtual or physical, regardless). I agree it's odd that you get only
2 of the 4 GB address space for your app under Win64 and the other 2
is reserved for the system. Of course the clear way forward is to make
a 64-bit app, I don't know where that is on the Racket roadmap.

Hey wait a second. Aren't Racket pointers a couple bits less than 32?
Like, say, 30 bits?  And that's 1 GB address space?   Q.E.D. ... ?

On Tue, Jul 13, 2010 at 2:03 PM, Jos Koot <jos.koot at telefonica.net> wrote:
> I run DrRacket on Window 7 premium home and can go up to 2 Gb. (I have a
> dual core 32 bit processor, 4 Gb memory of which 3 Gb for applications)
> What amazes me is, that when setting memory unlimited, DrRacket can't go
> over 2 Gb. In stead, when passing this limit, DrRacket is aborted by windows
> 7. (even when virtual memory limit of windows is set to 10 Gb)
> Jos
>
>> -----Original Message-----
>> From: users-bounces at racket-lang.org
>> [mailto:users-bounces at racket-lang.org] On Behalf Of Greg Hendershott
>> Sent: 13 July 2010 18:40
>> To: Matthew Flatt
>> Cc: plt-scheme
>> Subject: Re: [racket] DrRacket never uses more than 1 GB?
>>
>> Thanks Matthew. This was Racket 5.0. I swore "unlimited" was
>> set in DrRacket GUI. Maybe some bug where that was ignored?
>> I'll check again but meanwhile I reverted temporarily to PLT
>> Scheme 4.2.5. Another git bisect turned up a point where the
>> behavior changed (before that I wasn't running out of memory)
>> and I'm trying to figure out why. After I figure that out
>> I'll pop the stack and go back to Racket 5.0 to confirm
>> what's happening with that.
>>
>> > I don't think that's it. If you have a memory limit set,
>> then there's
>> > a factor of 2 involved, but that doesn't apply when you
>> don't have a
>> > memory limit.
>>
>> That's not what I'm seeing so far.
>>
>> Again this is all on Windows 7 64-bit, in case that matters.
>> Since Racket (and PLT Scheme) are 32-bit processes, 2 GB is
>> the max they
>> *could* get.
>>
>> But they never get 2 GB. Just 1 GB. On both PLT 4.2.5 and
>> Racket 5.0, when I set "unlimited" in the GUI I have never,
>> ever seen the DrXxx.exe process exceed 1 GB.  It always tops
>> out there and GC kicks in. If GC can't free up much, it just
>> gets stuck "flatlined" there at
>> 1 GB, and eventually the Visual C++ runtime error occurs.
>>
>> So:
>> [1] At some point my code started using much more memory.
>> That's my issue to figure out. Shouldn't need > 1 GB for this project.
>> [2] Even so, 1 GB seems to be a limit even if "unlimited" is set.
>>
>> On Tue, Jul 13, 2010 at 7:35 AM, Matthew Flatt
>> <mflatt at cs.utah.edu> wrote:
>> > At Mon, 12 Jul 2010 16:55:17 -0400, Greg Hendershott wrote:
>> >> Ah. If the GC needs 2X actual that would explain 2 GB -->
>> 1 GB usable.
>> >> That's a shame but I understand.
>> >
>> > I don't think that's it. If you have a memory limit set,
>> then there's
>> > a factor of 2 involved, but that doesn't apply when you
>> don't have a
>> > memory limit.
>> >
>> >> Since I posted, my git bisect suggests it wasn't my code that
>> >> changed, instead there was some change from PLT 4 to Racket.
>> >
>> > For "Racket", do you mean version 5.0? If you mean later
>> versions from
>> > git, I wonder whether commit 41d1daf53 from June 1 is relevant.
>> > (Commit 0e664e7c0 is needed along with 41d1daf53 under Windows.)
>> >
>> >
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