Re: iptables very slow after commit 784544739a25c30637397ace5489eeb6e15d7d49

David Miller
2009-04-13T01:13:53Z

From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Date: Sun, 12 Apr 2009 10:31:08 -0700

> On Sun, Apr 12, 2009 at 09:34:27PM +1000, Paul Mackerras wrote:
>> Paul E. McKenney writes:
>>
>> > If the generic implementation is needed only on !SMP systems, that
>> > could work. The architectures I would be worried about include
>> > powerpc and ia64, which I believe support 32-bit SMP builds.
>>
>> 32-bit powerpc doesn't have 64-bit atomic operations and does support
>> SMP.
>>
>> What about ARM? I thought they had 32-bit SMP these days as well.
>
> Some of Steve Hemminger's recent suggestions in this thread seem to me
> to avoid this whole issue nicely. But we will see! ;-)

I hope so.

Eventually it seems that all of the older 32-bit SMP platforms
will be run under a bus having to execute some many "efficient"
primitives using the "hash table of spinlocks" scheme for
synchronization.