O(N) Garbage collection?

[retard]

Sat, 19 Feb 2011 22:15:52 -0500, Nick Sabalausky wrote:

> "retard" <re at tard.com.invalid> wrote in message
> news:ijp7pa$1d34$1 at digitalmars.com...
>> Sat, 19 Feb 2011 14:32:27 -0500, dsimcha wrote:
>>
>>> On 2/19/2011 12:50 PM, Ulrik Mikaelsson wrote:
>>>> Just a thought; I guess the references to the non-GC-scanned strings
>>>> are held in GC-scanned memory, right? Are the number of such
>>>> references also increased linearly?
>>>
>>> Well, first of all, the benchmark I posted seems to indicate
>>> otherwise.
>>>   Second of all, I was running this program before on yeast DNA and it
>>> was ridiculously fast.  Then I tried to do the same thing on human DNA
>>> and it became slow as molasses.  Roughly speaking, w/o getting into
>>> the biology much, I've got one string for each gene.  Yeast have about
>>> 1/3 as many genes as humans, but the genes are on average about 100
>>> times smaller.  Therefore, the difference should be at most a small
>>> constant factor and in actuality it's a huge constant factor.
>>>
>>> Note:  I know I could make the program in question a lot more space
>>> efficient, and that's what I ended up doing.  It works now.  It's just
>>> that it was originally written for yeast, where space efficiency is
>>> obviously not a concern, and I would have liked to just try a one-off
>>> calculation on the human genome without having to rewrite portions of
>>> it.
>>
>> Probably one reason for this behavior is the lack of testing. My
>> desktop only has 24 GB of DDR3. I have another machine with 16 GB of
>> DDR2, but don't know how to combine the address spaces via clustering.
>> This would also horribly drag down GC performance. Even JVM is badly
>> tuned for larger systems, they might use the Azul Java runtimes
>> instead..
> 
> *Only* 24GB of DDR3, huh? :)
> 
> Makes me feel like a pauper: I recently upgraded from 1GB to 2GB of DDR1
> ;) (It actually had been 2GB a few years ago, but I cannablized half of
> it to build my Linux box.)
> 
> Out of curiosity, what are you running on that? (Multiple instances of
> Crysis? High-definition voxels?)

The largest processes are virtual machines, application servers, web 
server, IDE environment, several compiler instances in parallel. The Web 
browser also seems to have use for a gigabyte or two these days. As I 
recall, the memory was cheaper than now when I bought it. It's also 
cheaper than DDR2 or DDR (per gigabyte).