śr., 28 lip 2021 o 16:27 Olivier Matz <olivier.m...@6wind.com> napisał(a): > > Hi Michał, > > On Wed, Jul 14, 2021 at 12:02:32PM +0200, Michał Krawczyk wrote: > > pon., 12 lip 2021 o 19:03 Ghalem Boudour <ghalem.boud...@6wind.com> > > napisał(a): > > > > > > The DPDK ENA driver does not provide multi-segment tx offload capability. > > > Let's add DEV_TX_OFFLOAD_MULTI_SEGS to ports offload capability by > > > default. > > > > > > > Hi Ghalem, > > > > This patch enables announcement of the DEV_TX_OFFLOAD_MULTI_SEGS > > capability, but still the application may not request this offload. > > > > As ENA PMD currently assumes all the mbufs may have multiple segments > > (and we don't have fast-path for the other cases), I suggest > > overwriting this flag in the ena_dev_configure(), similar to what > > we're doing with the DEV_RX_OFFLOAD_RSS_HASH flag. > > To give some more context, our application currently checks if the > driver supports multi-segments by checking its capabilities, and asks > for the feature if it is advertised. > > When dealing with drivers that do not advertise this capability, our app > linearizes the segmented mbufs before sending them to the driver. > > I think this is the proper way to use the API: if the driver supports to > handle multisegmented mbufs, it should advertise the capability. > > Regards, > Olivier >
Hi Olivier, I agree we should advertise it. However, after advertising this option, the application should ask PMD to use this feature if I understand the offload API correctly. I was thinking about the PMD behavior if this option won't be requested by the application - it would be the same as for the multisegment setup, that's why I suggested to also override this feature at the configuration step. With the RSS hash feature we're doing exactly the same - first we're advertising that it's available, and then (if RSS was enabled), we're setting this offload as enabled, even though the application didn't request it explicitly. Anyway, I won't be holding push of this patch as we're close to rc3. @Ghalem, please add the fixline and Cc the d...@stable.org in the commit log, so we will have this commit backported. Thanks, Michal
