Re: vhash speed thread safeness

[ludo@gnu.org (Ludovic Courtès)]

Hi, Stefan,

Stefan Israelsson Tampe <stefan.itampe@gmail.com> skribis:

> I did some tests witha C-based vhash implementation, it's possible to 
> increse the speed by 30x compared to current vlist imlpementation in
> guile. It would be possible to get this speed today if one implemented
> vhash-assoc as a VM op. Anyway using the source as a standard lib will
> get you about 10x speed increase.

As we discussed, I don’t really like the idea of implementing that much
in C.

Also, I’d really like the optimization effort to be driven by actual
profiling data, such as C-level profiles of repeated calls to the
current ‘vhash-assoc’.  Have you tried that?

> Another pressing need is that vhashes are not thread safe,

Section 2.8 of Bagwell’s paper proposes a simple solution.  All that is
missing AFAICS is an atomic test-and-set VM op to implement it (which
may also be useful in other places.)

What do you think of this approach?

Thanks,
Ludo’.