[fpc-devel] Patch, font rendering on Arm-Linux devices.

Daniël Mantione daniel.mantione at freepascal.org
Thu Feb 28 11:25:20 CET 2008



Op Thu, 28 Feb 2008, schreef Vinzent Hoefler:

> On Thursday 28 February 2008 09:16, Daniël Mantione wrote:
>
>> Memory access. What happens is that the non-packed version causes
>> more cache misses.
>
> Please elaborate. If the (unaligned) data is crossing a cache-line, thus
> causing two full cache-line reads, I'd understand that, but once it's
> in the cache, it wouldn't matter anymore?

Yes, but if you have an array of them (as we have in this case), 
considerably more of these records will fit in the cache. Therefore you 
will have considerably less cache misses. This becomes even more serious 
when the processor in question does not have prefetching; in such case, 
traversing the array will cause cache miss after cache miss, a smaller 
array will then have less of these misses.

Daniël


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