On Thu, Feb 27, 2020 at 9:54 AM Ilya Maximets <i.maxim...@ovn.org> wrote: > > On 2/27/20 6:51 PM, William Tu wrote: > > On Thu, Feb 27, 2020 at 9:42 AM Ilya Maximets <i.maxim...@ovn.org> wrote: > >> > >> On 2/27/20 6:30 PM, William Tu wrote: > >>> The patch adds a new netdev class 'afxdp-nonpmd' to enable afxdp > >>> interrupt mode. This is similar to 'type=afxdp', except that the > >>> is_pmd field is set to false. As a result, the packet processing > >>> is handled by main thread, not pmd thread. This avoids burning > >>> the CPU to always 100% when there is no traffic. > >>> > >>> Tested-at: https://travis-ci.org/williamtu/ovs-travis/builds/655885506 > >>> Signed-off-by: William Tu <u9012...@gmail.com> > >>> --- > >>> NEWS | 3 +++ > >>> lib/netdev-afxdp.c | 20 +++++++++++++++++++- > >>> lib/netdev-linux.c | 20 ++++++++++++++++++++ > >>> lib/netdev-provider.h | 1 + > >>> lib/netdev.c | 1 + > >>> tests/system-afxdp.at | 23 +++++++++++++++++++++++ > >>> 6 files changed, 67 insertions(+), 1 deletion(-) > >>> > >>> diff --git a/NEWS b/NEWS > >>> index f62ef1f47ea8..594c55dc11d6 100644 > >>> --- a/NEWS > >>> +++ b/NEWS > >>> @@ -4,6 +4,9 @@ Post-v2.13.0 > >>> - OpenFlow: > >>> * The OpenFlow ofp_desc/serial_num may now be configured by setting > >>> the > >>> value of other-config:dp-sn in the Bridge table. > >>> + - AF_XDP: > >>> + * New netdev class 'afxdp-nonpmd' for netdev-afxdp to save CPU > >>> cycles > >>> + by enabling interrupt mode. > >>> > >>> > >>> v2.13.0 - 14 Feb 2020 > >>> diff --git a/lib/netdev-afxdp.c b/lib/netdev-afxdp.c > >>> index 482400d8d135..cd2c7c381139 100644 > >>> --- a/lib/netdev-afxdp.c > >>> +++ b/lib/netdev-afxdp.c > >>> @@ -169,6 +169,12 @@ struct netdev_afxdp_tx_lock { > >>> ); > >>> }; > >>> > >>> +static int nonpmd_cnt; /* Number of afxdp netdevs in non-pmd mode. */ > >>> +static bool > >>> +netdev_is_afxdp_nonpmd(struct netdev *netdev) { > >>> + return netdev_get_class(netdev) == &netdev_afxdp_nonpmd_class; > >>> +} > >>> + > >>> #ifdef HAVE_XDP_NEED_WAKEUP > >>> static inline void > >>> xsk_rx_wakeup_if_needed(struct xsk_umem_info *umem, > >>> @@ -1115,7 +1121,10 @@ netdev_afxdp_batch_send(struct netdev *netdev, int > >>> qid, > >>> struct netdev_linux *dev; > >>> int ret; > >>> > >>> - if (concurrent_txq) { > >>> + /* Lock is required when mixing afxdp pmd and nonpmd mode. > >>> + * ex: one device is created 'afxdp', the other is 'afxdp-nonpmd'. > >>> + */ > >>> + if (concurrent_txq || (nonpmd_cnt != 0)) { > >> > >> I'm confused about this change. Are you expecting same device being > >> opened twice with different netdev type? Database should not allow this. > > > > Not the same device. > > > > For example, dev1 opened as 'afxdp', and dev2 opened as 'afxdp-nonpmd'. > > When dev2 receives a packet and send to dev1, the main thread used by dev2 > > is calling the send(), while it is possible that dev2's pmd thread is > > also calling > > send(). So need a lock here. > > But they will send to different tx queues.
OK, I think you are talking about the XPS feature (dynamic txqs). I thought XPS can only work when all between pmd threads. So adding a lock here. The patch currently doesn't work without the lock. Let me investigate more. Thanks William _______________________________________________ dev mailing list d...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-dev
