Hash benchmarks

[Luben Karavelov]

 On Thu, 15 Mar 2012 11:51:37 +1100, Vasily Chekalkin <bacek at bacek.com> 
 wrote:
> Yay!
>
> Can you also try parrot with int keys and float values? Just for 
> curiosity.
>
> --
> Bacek

 I was looking to make it possible (yesterday I pushed a commit to make 
 iterating
 Hash PMCs with int keys possible) but it is not at the moment.

 There as also some uncertainty how to proceed. At my PC(amd64) FLOATVAL 
 is
 defined as synonym for double (64 bits). Hash values have maximum size 
 of a
 pointer and there are architectures that have
   sizeof(void *) < sizeof(double)
 i386 to be precise.

 So if we want to store FLOATVAL directly in hash tables we have 2 
 choises:

 1. Make FLOATVAL = float (32 bit) on platforms where
    sizeof(void *) < sizeof(double)

 I am not sure if this is the right choice - what guarantees do we give 
 for
 FLOATVALs (Num registers)?

 2. make hashval field big enough for doubles - it will pose some 
 penalty on
    32bit platforms

 In either case it will not be the major case of use of hash tables. I 
 am not
 even sure if Rakudo could do hashes with int keys

 If we have consensus how to proceed I am willing to code it even if it 
 is not
 the major use case.

 Best regards

-- 
 Luben Karavelov