From: Michal Suchanek <hramrach@...>
Date: 2010-05-19T23:48:10+09:00
Subject: Re: 64 bit ruby interpreter

On 19 May 2010 16:31, Michal Suchanek <hramrach@centrum.cz> wrote:
> On 19 May 2010 15:21, Bruno Sousa <brgsousa@gmail.com> wrote:
>> Ops :P
>>
>> Simone, did you noticed a performance improvement?
>>
>
> I can say I noticed improvement in the amount of available memory.
>
> 32bit systems typically allow mapping only up to 2G of ram to a single process.
>

Also you will notice that 64bit systems can do integer arithmetics on
larger range of numbers.

If you did lots of integer calculations with numbers in the range
1073741824-2305843009213693952 you would notice a speed improvement I
guess because fixnums are much faster than bignums.

You would likely not notice a difference unless you need lots of
memory or you do lots of integer math in the range which requires
30-62 bits to represent.

n=1 ; (1..64).each { STDOUT <<  n << " " << n.class << "\n" ; n = n*2 }

1 Fixnum
2 Fixnum
4 Fixnum
8 Fixnum
16 Fixnum
...
268435456 Fixnum
536870912 Fixnum
1073741824 Bignum
2147483648 Bignum
...
on a 32 bit system and

1 Fixnum
2 Fixnum
4 Fixnum
8 Fixnum
16 Fixnum
...
1152921504606846976 Fixnum
2305843009213693952 Fixnum
4611686018427387904 Bignum
9223372036854775808 Bignum

on a 64bit system.