On 22.04.2021 13:48, Stefano Garzarella wrote: > On Thu, Apr 22, 2021 at 01:29:54PM +0300, Arseny Krasnov wrote: >> On 22.04.2021 13:02, Stefano Garzarella wrote: >>> On Thu, Apr 22, 2021 at 12:40:17PM +0300, Arseny Krasnov wrote: >>>> On 22.04.2021 11:46, Stefano Garzarella wrote: >>>>> On Wed, Apr 21, 2021 at 06:06:28PM +0300, Arseny Krasnov wrote: >>>>>> Thank You, i'll prepare next version. Main question is: does this >>>>>> approach(no SEQ_BEGIN, SEQ_END, 'msg_len' and 'msg_id') considered >>>>>> good? In this case it will be easier to prepare final version, because >>>>>> is smaller and more simple than previous logic. Also patch to spec >>>>>> will be smaller. >>>>> Yes, it's definitely much better than before. >>>>> >>>>> The only problem I see is that we add some overhead per fragment >>>>> (header). We could solve that with the mergeable buffers that Jiang is >>>>> considering for DGRAM. >>>> If we are talking about receive, i think, i can reuse merge logic for >>> Yep, for TX the guest can potentially enqueue a big buffer. >>> Maybe it's still worth keeping a maximum size and fragmenting as we do >>> now. >>> >>>> stream sockets, the only difference is that buffers are mergeable >>>> until previous EOR(e.g. previous message) bit is found in rx queue. >>>> >>> I got a little lost. >>> Can you elaborate more? >> I'm talking about 'virtio_transport_recv_enqueue()': it tries to copy >> >> data of new packet to buffer of tail packet in rx queue. In case of >> >> SEQPACKET i can reuse it, just adding logic that check EOR bit of >> >> tail packet. > This might be a good idea. > It doesn't save us the transmitted header though, but at least it saves > us from queuing it. > Even if with SEQPACKET I don't expect small packets, since it's the > driver that divides them and I think it does everything to use the > maximum available. > > Instead the mergeable buffers I was referring to are based on the > virito-net feature VIRTIO_NET_F_MRG_RXBUF. > Jiang is investigating whether we can reuse them for DGRAM. Understand, thank you > > Thanks, > Stefano > >
