Re: [PATCH 3/3] Convert the UDP hash lock to RCU

Evgeniy Polyakov
2008-10-07T14:45:43Z

On Tue, Oct 07, 2008 at 09:16:13AM -0500, Christoph Lameter (cl@linux-foundation.org) wrote:
> > I tested skb destruction via RCU path, and got 2.5 times worse numbers
> > with small-packets-bulk-transfer workload.
>
> Was this with regular RCU freeing? This will cool down the cacheline before
> frees. You need SLAB_DESTROY_BY_RCU to keep the objects cache hot.

I believe there were no SLAB_DESTROY_BY_RCU 2 yars ago :)

It was pure call_rcu(&skb->rcu, real_skb_freeing), where
real_skb_freeing() just did usual kfree().

--
Evgeniy Polyakov