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

From: Evgeniy Polyakov <[email-masked]>
Date: Tue, 7 Oct 2008 18:29:02 +0400

On Tue, Oct 07, 2008 at 09:16:13AM -0500, Christoph Lameter ([email-masked]) 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