Messages in this thread | | | Date | Fri, 7 Sep 2012 03:06:23 +0300 | From | "Michael S. Tsirkin" <> | Subject | Re: [PATCH v2 2/2] virtio-ring: Allocate indirect buffers from cache when possible |
| |
On Fri, Sep 07, 2012 at 09:19:04AM +0930, Rusty Russell wrote: > "Michael S. Tsirkin" <mst@redhat.com> writes: > > > On Thu, Sep 06, 2012 at 05:27:23PM +0930, Rusty Russell wrote: > >> "Michael S. Tsirkin" <mst@redhat.com> writes: > >> > Yes without checksum net core always linearizes packets, so yes it is > >> > screwed. > >> > For -net, skb always allocates space for 17 frags + linear part so > >> > it seems sane to do same in virtio core, and allocate, for -net, > >> > up to max_frags + 1 from cache. > >> > We can adjust it: no _SG -> 2 otherwise 18. > >> > >> But I thought it used individual buffers these days? > > > > Yes for receive, no for transmit. That's probably why > > we should have the threshold per vq, not per device, BTW. > > Can someone actually run with my histogram patch and see what the real > numbers are? > > I'm not convinced that the ideal 17-buffer case actually happens as much > as we think. And if it's not happening with this netperf test, we're > testing the wrong thing. > > Thanks, > Rusty.
hope to play with it next week
| |