On Wed, Jul 19, 2023 at 12:50:04AM +0000, Bobby Eshleman wrote: > Hey all! > > This series introduces support for datagrams to virtio/vsock. > > It is a spin-off (and smaller version) of this series from the summer: > https://lore.kernel.org/all/cover.1660362668.git.bobby.eshleman@xxxxxxxxxxxxx/ > > Please note that this is an RFC and should not be merged until > associated changes are made to the virtio specification, which will > follow after discussion from this series. > > Another aside, the v4 of the series has only been mildly tested with a > run of tools/testing/vsock/vsock_test. Some code likely needs cleaning > up, but I'm hoping to get some of the design choices agreed upon before > spending too much time making it pretty. > > This series first supports datagrams in a basic form for virtio, and > then optimizes the sendpath for all datagram transports. > > The result is a very fast datagram communication protocol that > outperforms even UDP on multi-queue virtio-net w/ vhost on a variety > of multi-threaded workload samples. > > For those that are curious, some summary data comparing UDP and VSOCK > DGRAM (N=5): > > vCPUS: 16 > virtio-net queues: 16 > payload size: 4KB > Setup: bare metal + vm (non-nested) > > UDP: 287.59 MB/s > VSOCK DGRAM: 509.2 MB/s > > Some notes about the implementation... > > This datagram implementation forces datagrams to self-throttle according > to the threshold set by sk_sndbuf. It behaves similar to the credits > used by streams in its effect on throughput and memory consumption, but > it is not influenced by the receiving socket as credits are. > > The device drops packets silently. > > As discussed previously, this series introduces datagrams and defers > fairness to future work. See discussion in v2 for more context around > datagrams, fairness, and this implementation. it's a big thread - can't you summarize here? > Signed-off-by: Bobby Eshleman <bobby.eshleman@xxxxxxxxxxxxx> could you give a bit more motivation? which applications do you have in mind? for example, on localhost loopback datagrams are actually reliable and a bunch of apps came to depend on that even if they shouldn't. > --- > Changes in v5: > - teach vhost to drop dgram when a datagram exceeds the receive buffer > - now uses MSG_ERRQUEUE and depends on Arseniy's zerocopy patch: > "vsock: read from socket's error queue" > - replace multiple ->dgram_* callbacks with single ->dgram_addr_init() > callback > - refactor virtio dgram skb allocator to reduce conflicts w/ zerocopy series > - add _fallback/_FALLBACK suffix to dgram transport variables/macros > - add WARN_ONCE() for table_size / VSOCK_HASH issue > - add static to vsock_find_bound_socket_common > - dedupe code in vsock_dgram_sendmsg() using module_got var > - drop concurrent sendmsg() for dgram and defer to future series > - Add more tests > - test EHOSTUNREACH in errqueue > - test stream + dgram address collision > - improve clarity of dgram msg bounds test code > - Link to v4: https://lore.kernel.org/r/20230413-b4-vsock-dgram-v4-0-0cebbb2ae899@xxxxxxxxxxxxx > > Changes in v4: > - style changes > - vsock: use sk_vsock(vsk) in vsock_dgram_recvmsg instead of > &sk->vsk > - vsock: fix xmas tree declaration > - vsock: fix spacing issues > - virtio/vsock: virtio_transport_recv_dgram returns void because err > unused > - sparse analysis warnings/errors > - virtio/vsock: fix unitialized skerr on destroy > - virtio/vsock: fix uninitialized err var on goto out > - vsock: fix declarations that need static > - vsock: fix __rcu annotation order > - bugs > - vsock: fix null ptr in remote_info code > - vsock/dgram: make transport_dgram a fallback instead of first > priority > - vsock: remove redundant rcu read lock acquire in getname() > - tests > - add more tests (message bounds and more) > - add vsock_dgram_bind() helper > - add vsock_dgram_connect() helper > > Changes in v3: > - Support multi-transport dgram, changing logic in connect/bind > to support VMCI case > - Support per-pkt transport lookup for sendto() case > - Fix dgram_allow() implementation > - Fix dgram feature bit number (now it is 3) > - Fix binding so dgram and connectible (cid,port) spaces are > non-overlapping > - RCU protect transport ptr so connect() calls never leave > a lockless read of the transport and remote_addr are always > in sync > - Link to v2: https://lore.kernel.org/r/20230413-b4-vsock-dgram-v2-0-079cc7cee62e@xxxxxxxxxxxxx > > --- > Bobby Eshleman (13): > af_vsock: generalize vsock_dgram_recvmsg() to all transports > af_vsock: refactor transport lookup code > af_vsock: support multi-transport datagrams > af_vsock: generalize bind table functions > af_vsock: use a separate dgram bind table > virtio/vsock: add VIRTIO_VSOCK_TYPE_DGRAM > virtio/vsock: add common datagram send path > af_vsock: add vsock_find_bound_dgram_socket() > virtio/vsock: add common datagram recv path > virtio/vsock: add VIRTIO_VSOCK_F_DGRAM feature bit > vhost/vsock: implement datagram support > vsock/loopback: implement datagram support > virtio/vsock: implement datagram support > > Jiang Wang (1): > test/vsock: add vsock dgram tests > > drivers/vhost/vsock.c | 64 ++- > include/linux/virtio_vsock.h | 10 +- > include/net/af_vsock.h | 14 +- > include/uapi/linux/virtio_vsock.h | 2 + > net/vmw_vsock/af_vsock.c | 281 ++++++++++--- > net/vmw_vsock/hyperv_transport.c | 13 - > net/vmw_vsock/virtio_transport.c | 26 +- > net/vmw_vsock/virtio_transport_common.c | 190 +++++++-- > net/vmw_vsock/vmci_transport.c | 60 +-- > net/vmw_vsock/vsock_loopback.c | 10 +- > tools/testing/vsock/util.c | 141 ++++++- > tools/testing/vsock/util.h | 6 + > tools/testing/vsock/vsock_test.c | 680 ++++++++++++++++++++++++++++++++ > 13 files changed, 1320 insertions(+), 177 deletions(-) > --- > base-commit: 37cadc266ebdc7e3531111c2b3304fa01b2131e8 > change-id: 20230413-b4-vsock-dgram-3b6eba6a64e5 > > Best regards, > -- > Bobby Eshleman <bobby.eshleman@xxxxxxxxxxxxx>
