Subject: Re: Some observations about DMA segment count
To: None <>
From: Jason R Thorpe <>
List: tech-net
Date: 07/26/2001 12:02:09
On Tue, Jul 24, 2001 at 08:32:41PM -0700, Jason R Thorpe wrote:

 > Thoughts on what to do about this?  There should certainly be room in front
 > of the packet for the link header, and we should try to avoid allocating
 > the extra mbuf.

So, FWIW, I fixed this.  See M_READONLY() in sys/mbuf.h, and how it is

Between this and another change (which I will commit shortly) to use
pool_cache_get() for mbuf/cluster allocation, I've gained another 2000KB/sec
on my Gig-E benchmarks with the Sundance TC9021 chip.

...time to do another kernel profile, I suppose :-)

        -- Jason R. Thorpe <>