On 2/27/20 6:51 PM, William Tu wrote: > On Thu, Feb 27, 2020 at 9:42 AM Ilya Maximets <[email protected]> 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 <[email protected]> >>> --- >>> 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. _______________________________________________ dev mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-dev
