Re: data structure lockin

[Richard Mortier <Richard.Mortier@xxxxxxxxxxxxxxxx>]

nice... :)

On 16 Jan 2013, at 22:38, Anil Madhavapeddy wrote:

> Continuing the topic of data structures, I noticed a slowdown for the DNS 
> performance after the recent conversion to cstruct.  While the memoized 
> version (which caches marshalled packets) was about the same performance, the 
> normal one was much slower (even worse than BIND).
> 
> Thomas did some profiling today, and it turns out that the use of a mutable 
> Hashtbl for tracking label compression results in very bad performance, since 
> the string lists all have hash collisions and ends up linearising the 
> structure.  He converted it to use a purely functional Map instead (which 
> just lives on the minor heap since it's only needed for one packet parse 
> cycle), and performance is right back where it should be!
> 
> https://github.com/samoht/ocaml-dns/commit/fd68be3850353f2fb981b100bf04562ae0d99a1e
> 
> (mainly fyi for Mort, but useful for others too)
> 
> -anil


-- 
Cheers,

R.




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