Re: phk malloc, was (Re: ptmalloc2)

[Ted Unangst <tedu@xxxxxxxxxxxxx>]

On Thu, 17 Feb 2005, Jonathan Dama wrote:

> Ideally, you ought to be able to fill malloc's backing keg
> with allocations from mmap permitting MAXDSIZ to be left
> alone.  (phk reports that mmap is x5 slower than brk--see:
> http://lists.swelltech.com/pipermail/squid-users-archive/1996-August/000666.html
> http://lists.swelltech.com/pipermail/squid-users-archive/1996-August/000663.html
> --but this could be made up by simply going to the kernel
> less frequently--see further:)

in the real world, the slowdown is more like 10% for something like 
buildworld.  not great, but not crippling like 500% would be.

> Moreover, it may even brk for every additional 4K of
> allocation via malloc.

if you allocate 4k at a time, yes it does.


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