[fpc-devel] x86_64 Optimizer Overhaul

[Jonas Maebe]

On 15/12/18 21:04, Ben Grasset wrote:
> On Sat, Dec 15, 2018 at 2:43 PM Jonas Maebe <jonas at freepascal.org 
> <mailto:jonas at freepascal.org>> wrote:
> 
>     That is incorrect.
> 
> I didn't mean that it doesn't *care* about being fast, but more that it 
> will not necessarily use more memory in all cases that it might result 
> in a speed gain, and generally is more concerned with a "balanced" 
> approach, which is what I've always heard to be the case. Is that really 
> not true at all?

It makes use of thread-local heaps and pooling for small allocation 
sizes, both of which are aimed at increasing speed. For blocks that are 
too large for the pools, there are no particular trade-offs afaik (it's 
just a linked list of free blocks per thread that can be reused). It's 
probably true that it will have a smaller memory footprint than 
something like jemalloc, at least as long as memory fragmentation (which 
jemalloc is very good at avoiding) doesn't take the upper hand.


Jonas