mbuf layout optimizations

[Barney Cordoba]

--- On Fri, 6/19/09, Jeff Roberson <jroberson at jroberson.net> wrote:

> From: Jeff Roberson <jroberson at jroberson.net>
> Subject: mbuf layout optimizations
> To: net at freebsd.org, current at freebsd.org
> Date: Friday, June 19, 2009, 5:12 AM
> http://people.freebsd.org/~jeff/mbuf2.diff
> 
> Hello,
> 
> This is a call for testers and feedback on my mbuf layout
> improvements. I'm trying to decide whether I will push to
> have these included in 8.0. After reducing the scope
> slightly from my last patch, I have not encountered any
> problems.  Kip Macy has also been using it for the past
> few weeks without issue.
> 
> You should not expect any functional changes from this
> patch.  The goal is mostly to pave the way fors more
> sensible mbuf handling in the future, although it does offer
> a few performance benefits.
> 
> The only issue is that cxgb support requires another set of
> patches from Kip.  If anyone needs those I will prod
> him to reply with that diff.
> 
> Thanks,
> Jeff

I thought that the purpose of m_tags was to keep individual applications from having to "patch" mbufs. Has that idea proven to be too
performance-challenged?

Barney