[Qemu-devel] [PATCH v3 0/5] Add netmap backend offloadings support

[Vincenzo Maffione <v.maffione@gmail.com>]

The purpose of this patch series is to add offloadings support
(TSO/UFO/CSUM) to the netmap network backend, and make it possible
for the paravirtual network frontends (virtio-net and vmxnet3) to
use it.
In order to achieve this, these patches extend the existing
net.h interface to add abstract operations through which a network
frontend can manipulate backend offloading features, instead of
directly calling TAP-specific functions.

Guest-to-guest performance before this patches for virtio-net + netmap:

    TCP_STREAM                  5.0 Gbps
    TCP_RR                      12.7 Gbps
    UDP_STREAM (64-bytes)       790 Kpps

Guest-to-guest performance after this patches for virtio-net + netmap:

    TCP_STREAM                  21.4 Gbps
    TCP_RR                      12.7 Gbps
    UDP_STREAM (64-bytes)       790 Kpps

Experiment details:
    - Processor: Intel i7-3770K CPU @ 3.50GHz (8 cores)
    - Memory @ 1333 MHz
    - Host O.S.: Archlinux with Linux 3.11
    - Guest O.S.: Archlinux with Linux 3.11

    - QEMU command line:
        qemu-system-x86_64 archdisk.qcow -snapshot -enable-kvm -device virtio-net-pci,ioeventfd=on,mac=00:AA:BB:CC:DD:01,netdev=mynet -netdev netmap,ifname=vale0:01,id=mynet -smp 2 -vga std -m 3G


******** Changes against the previous version ***********
NOTE: Now the VALE switch supports the offloadings, meaning that TCP/UDP will work
      even between a virtio-net guest with offloadings enabled and another
      guest with offloadings disabled. This has been achieved without performance loss
      on the "fast" case (e.g. two virtio-net-guest communicating with offloadings on).

(1) removed the second commit of the previous version, which was
    intended to remove tap_using_vnet_hdr()
(2) the last commit has been revised: NETMAP_BDG_OFFSET becomes
    NETMAP_BDG_VNET_HDR, netmap_set_offload() implemented and
    netmap_has_vnet_hdr_len() rewritten.


Vincenzo Maffione (5):
  net: change vnet-hdr TAP prototypes
  net: extend NetClientInfo for offloading
  net: TAP uses NetClientInfo offloading callbacks
  net: virtio-net and vmxnet3 use offloading API
  net: add offloading support to netmap backend

 hw/net/virtio-net.c | 16 +++++--------
 hw/net/vmxnet3.c    | 12 ++++------
 include/net/net.h   | 19 +++++++++++++++
 include/net/tap.h   |  4 ++--
 net/net.c           | 55 +++++++++++++++++++++++++++++++++++++++++++
 net/netmap.c        | 68 ++++++++++++++++++++++++++++++++++++++++++++++++++++-
 net/tap-win32.c     |  8 +++----
 net/tap.c           | 12 +++++++---
 8 files changed, 167 insertions(+), 27 deletions(-)

-- 
1.8.5.2