Op Tue, 26 Feb 2008, schreef Luiz Americo Pereira Camara:
Yury Sidorov wrote:
The patch removes packed record for some platforms.
IMO packed can be removed for all platforms. It will gain some speed.
I'd like to understand more this issue.
Why are non packed records faster?
Cache trashing. One of the most underestimated performance killers in
modern software.
The difference occurs at memory allocation or at memory access?
Memory access. What happens is that the non-packed version causes more
cache misses. A cache miss costs many cycles on a modern cpu, a misaligned
read just costs an extra memory access (which is fast if cached) on x86,
and extra load instruction on ARM. This much cheaper than a chache miss.
Daniël
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