L;w
> -----Original Message----- > From: dev [mailto:dev-boun...@dpdk.org] On Behalf Of Gaëtan Rivet > Sent: Thursday, June 01, 2017 5:38 PM > To: Stephen Hemminger <step...@networkplumber.org> > Cc: dev@dpdk.org > Subject: Re: [dpdk-dev] [PATCH v4 08/12] net/failsafe: support offload > capabilities > > On Wed, May 31, 2017 at 08:23:09AM -0700, Stephen Hemminger wrote: > > On Mon, 29 May 2017 15:42:20 +0200 > > Gaetan Rivet <gaetan.ri...@6wind.com> wrote: > > > > > Signed-off-by: Gaetan Rivet <gaetan.ri...@6wind.com> > > > Acked-by: Olga Shern <ol...@mellanox.com> > > > --- > > > doc/guides/nics/features/failsafe.ini | 6 ++ > > > drivers/net/failsafe/failsafe_ops.c | 131 > +++++++++++++++++++++++++++++++++- > > > 2 files changed, 135 insertions(+), 2 deletions(-) > > > > Once again what about case of dumb synthetic NIC combined with SR-IOV > VF? > > The VF has offloads the virtual NIC does not. > > > > The rules for capabilities are a little complicated. > In the case both VF and the virtual NIC are present at launch, then the > logical > AND is done both their capabilities sets. > If one has additional capabilities that the user is requesting, and the > fail-safe > recognize them (currently, all RX offloads, as TX offloads were not yet > expressed by flags), and this capability is not supported by one slave, then > this offload is disabled in the configuration. > > > What about late plugin. how do you program the offloads of the later > > arriving VF device. > > If the VF is not present at launch, then the fail-safe reads only the set of > capabilities from the fallback device. It does not have to do any AND-ing of > the flags. > > The consequence is that upon plugin of the VF, the latter has to respect the > current running configuration. Probing will actually fail if some capability > is not > supported (depending on PMDs), and the running configuration is not > updated as it is considered "live". > > There are only two solutions to this, either: > > * Complicate a lot the fail-safe design and the rules applied in > the decision made on NIC configuration. The user then has bad > surprises upon seeing that his performance have been degraded > for arcane reasons. > > * Emulate in software the offloads and try to advertize as many as > possible. This is done for example in the TAP PMD for some flags, > allowing those offloads to be used with hardware NICs. > The user then has a clear view of the available offloads by comparing > both sets of capabilities. > > -- > Gaëtan Rivet > 6WIND
