From: Xavier Shay <xavier-list@...>
Date: 2011-05-05T08:23:02+09:00
Subject: [ruby-core:36009] Re: require performance on 1.9

On 3/05/11 9:03 PM, Xavier Shay wrote:
> I have tracked down the remaining performance loss from the above graph
> to load.c:152. On every require, StringValuePtr is called on every
> loaded feature. ruby18 does this also, but my hunch is this is more
> expensive in 1.9 perhaps because of encoding or something?
>
> Can loaded_features ever shrink? Can a value in loaded_features change?
> Is there a sane way to cache this value?
Can anyone shed some light on any of these? I'm really keen to work on 
this I just need a pointer in the right direction.


> I tried keeping a really stupid
> cache of the return values in a char** but that idea crashed and burned.
>
> In summary, there are two problems that are making ruby 1.9 requires so
> much slower than 1.8:
> 1) The loaded_feature_path function, which I cannot find a use for
> (load.c:158)
> 2) The repeated calling of StringValuePtr (load.c:152) for every
> loaded_feature on every require
>
> With the above two code paths disabled, require time is back down to
> ruby18 levels, as per this graph*:
> https://skitch.com/xaviershay/r7jid/tc-load-time
>
> Any ideas for progressing on #2?
>
> Cheers,
> Xavier
>
> * of course, disabling #2 is definitely invalid, this is just for sake
> of demonstration)
>