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Re: SLAB allocator now the default.

From: David Leimbach <leimy2k@xxxxxxx>
Date: Sun, 28 Sep 2003 11:35:22 -0500

On Sep 28, 2003, at 9:22 AM, Hiten Pandya wrote:

Matthew Dillon wrote:

The slab allocator is now the default. The NO_KMEM_MAP and
USE_SLAB_ALLOCATOR options have been removed.
USE_KMEM_MAP and NO_SLAB_ALLOCATOR options have temporarily been added,
but these too will be removed (along with the old malloc and kmem_map
code) in about a week.



	I haven't looked at the Slab-alloc code recently, but I am
	wondering if you are planning to remove the power-of-2 alignment
	stuff out of malloc()?

Doesn't power of two alignment make it easier on some CPUs internally to access
data? If a person wanted to access a word overlapping two word's alignment would it
not take two bus accesses to get that data [or two cache reads... what have you]

Do the benefits of not having power of two alignment outweigh this?

	From the many papers I have been reading in the last couple of
	weeks, it seems that power-of-2 alignment seems to cause a lot
	of performance degradation in SMP cases, and cache issues.

A good example of this demonstration is in Bonwick's papers.

	I understand this would be quite a lengthy and tedious procedure
	but it is something that I have been wondering.


Hiten Pandya

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