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From dean gaudet <d...@arctic.org>
Subject Re: SMS as Pools Patch
Date Thu, 12 Jul 2001 11:00:50 GMT
On Wed, 11 Jul 2001, Justin Erenkrantz wrote:

> Well, part of it is inertia and an optimization.  The current pool
> code adds an additional 4096 bytes to any allocation in order to
> make any allocation of <4096 bytes be done for free since we have
> already allocated it - we just tack it on to the block that we have
> just allocated.  Dean Gaudet may have more explanation as to why we
> do this, but the current pool code definitely does this.

nope you've pretty much summed it up.  it is a questionable optimisation
though.

> I'd like to see how it performs when MIN_FREE is set to 0.  We'd suck
> at little allocation (actually not - consider that MIN_ALLOC is 4096,
> so if we allocate a bunch of small things in a row, this optimization
> is still present - just that if we allocate >4096 bytes, we don't get
> anything for free).

i think after i ironed out a few quirks i didn't bother playing with
MIN_FREE (which was there before i started playing with the allocator)...
even though it seemed somewhat damaging because of the odd sized blocks it
started to create on the freelist.

it's probably best to have MIN_FREE 0.

-dean


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