[ovs-dev] [PATCH] INSTALL.DPDK.md: Clarify DPDK arguments.

[Ben Pfaff]

On Tue, Dec 08, 2015 at 04:41:37PM +0000, Gray, Mark D wrote:
> > -----Original Message-----
> > From: dev [mailto:dev-bounces at openvswitch.org] On Behalf Of Kevin
> > Traynor
> > Sent: Monday, December 7, 2015 5:58 PM
> > To: dev at openvswitch.org
> > Subject: [ovs-dev] [PATCH] INSTALL.DPDK.md: Clarify DPDK arguments.
> > 
> > Add some information about the DPDK -c and -n parameters.
> > 
> > Signed-off-by: Kevin Traynor <kevin.traynor at intel.com>
> > Reported-by: Zoltan Kiss <zoltan.kiss at linaro.org>
> > ---
> >  INSTALL.DPDK.md |   14 ++++++++++++--
> >  1 files changed, 12 insertions(+), 2 deletions(-)
> > 
> > diff --git a/INSTALL.DPDK.md b/INSTALL.DPDK.md index 96b686c..ee016da
> > 100644
> > --- a/INSTALL.DPDK.md
> > +++ b/INSTALL.DPDK.md
> > @@ -145,8 +145,18 @@ Using the DPDK with ovs-vswitchd:
> > 
> >     DPDK configuration arguments can be passed to vswitchd via `--dpdk`
> >     argument. This needs to be first argument passed to vswitchd process.
> > -   dpdk arg -c is ignored by ovs-dpdk, but it is a required parameter
> > -   for dpdk initialization.
> > +   The DPDK configuration arguments are passed to DPDK during DPDK
> > +   initialization.
> > +
> > +   The DPDK -c coremask is a required argument. To avoid wasted resources
> > +   only one core should be set. The standard OVS threads (e.g. main
> > +   process, handler, revalidator) will run on the core that is specified.
> 
> Might be worth mentioning that then there is a corresponding potential decrease
> in performance of revalidation and flow handling. 

With the kernel datapath, OVS sets up flows and revalidates them on
multiple cores.  You're saying that with DPDK it only uses one core?
Why?