Hi all > -----Original Message----- > From: Noa Ezra > Sent: Thursday, June 20, 2019 8:58 AM > To: Maxime Coquelin <maxime.coque...@redhat.com> > Cc: Matan Azrad <ma...@mellanox.com>; dev@dpdk.org > Subject: RE: [PATCH 2/2] net/vhost: support mrg-rxbuf disabling > > Hi Maxime, > Thanks for your comment, please see below. > > > -----Original Message----- > > From: Maxime Coquelin [mailto:maxime.coque...@redhat.com] > > Sent: Wednesday, June 19, 2019 12:10 PM > > To: Noa Ezra <n...@mellanox.com> > > Cc: Matan Azrad <ma...@mellanox.com>; dev@dpdk.org > > Subject: Re: [PATCH 2/2] net/vhost: support mrg-rxbuf disabling > > > > Hi Noa, > > > > On 6/19/19 8:13 AM, Noa Ezra wrote: > > > Rx mergeable buffers is a virtio feature that allows chaining of > > > multiple virtio descriptors to handle large packet size. > > > This behavior is supported and enabled by default, however in case > > > the user knows that rx mergeable buffers are not needed, he can > > > disable the feature. > > > The user should also set mrg_rxbuf=off in virtual machine's xml. > > > > I'm not sure to understand why it is needed, as the vhost-user library > > supports the feature, it's better to let it being advertised. > > > > As you say, it is up to the user to disable it in the VM's XML. > > Done this way, the feature won't be negotiated. > > > I agree with you, I'll remove this patch from the series.
Are you sure that no performance impact exists for redundant merg-rx-buf configuration here? What if the second side want it and the current side no? It may be that the vhost PMD user may want to disable it to save performance from some reasons, no?
