[Scummvm-devel] Kyrandia engine loading is slow on the DS

Bertrand Augereau bertrand_augereau at yahoo.fr
Sat Aug 23 13:34:10 CEST 2008


Well, if I got it right, the map is expanded when it is 66% full instead of 75% so this might have an impact, no?I doubt this is an issue though.
Some changes should be done to the memory pool anyway that would have an influence on the hashmaps:* it should grow exponentially instead of linearly* it might have a template size_t parameter that describe in situ storage that is served before heap memory.
--- En date de : Sam 23.8.08, Max Horn <max at quendi.de> a écrit :
De: Max Horn <max at quendi.de>
Objet: Re: [Scummvm-devel] Kyrandia engine loading is slow on the DS
À: "Bertrand Augereau" <bertrand_augereau at yahoo.fr>
Cc: "scummvm-devel devel" <scummvm-devel at lists.sourceforge.net>
Date: Samedi 23 Août 2008, 1h03

Am 22.08.2008 um 14:08 schrieb Bertrand Augereau:

[...]
> Additionnaly, I checked the new hash map put by Max on the tracker,  
> and it looks that the DS might benefit from the decreased overhead  
> in map lookups.
>
> Yet I didn't study the memory tradeoffs implied so it might not be  
> that safe for this version on tight devices.
>

Memory tradeoff? The only one I am aware of is the fact that now  
instead of a default size of 53, the default size is 8 entries  
(allowing 2/3*8=5 active entries), which is enough for maybe 90% of  
the hashmaps we use, but OTOH means that that more collisions may  
occur. But overall, with the new hashmap, memory usage should be  
decreased, and I'd hope speed should be improved, too, despite some  
more lookup collisions; however, it is very easy to change the initial  
table size from 8 to e.g. 32 or 64.


Cheers,
Max



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