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author | Alexei Starovoitov | 2018-05-25 03:36:16 +0200 |
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committer | Alexei Starovoitov | 2018-05-25 03:36:16 +0200 |
commit | 10f678683e4026e43524b0492068a371d00fdeed (patch) | |
tree | 069715fbcf7b0f4b73103861fd0a111e143b5705 /drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | |
parent | Merge branch 'bpf-task-fd-query' (diff) | |
parent | samples/bpf: xdp_monitor use err code from tracepoint xdp:xdp_devmap_xmit (diff) | |
download | kernel-qcow2-linux-10f678683e4026e43524b0492068a371d00fdeed.tar.gz kernel-qcow2-linux-10f678683e4026e43524b0492068a371d00fdeed.tar.xz kernel-qcow2-linux-10f678683e4026e43524b0492068a371d00fdeed.zip |
Merge branch 'xdp_xmit-bulking'
Jesper Dangaard Brouer says:
====================
This patchset change ndo_xdp_xmit API to take a bulk of xdp frames.
When kernel is compiled with CONFIG_RETPOLINE, every indirect function
pointer (branch) call hurts performance. For XDP this have a huge
negative performance impact.
This patchset reduce the needed (indirect) calls to ndo_xdp_xmit, but
also prepares for further optimizations. The DMA APIs use of indirect
function pointer calls is the primary source the regression. It is
left for a followup patchset, to use bulking calls towards the DMA API
(via the scatter-gatter calls).
The other advantage of this API change is that drivers can easier
amortize the cost of any sync/locking scheme, over the bulk of
packets. The assumption of the current API is that the driver
implemementing the NDO will also allocate a dedicated XDP TX queue for
every CPU in the system. Which is not always possible or practical to
configure. E.g. ixgbe cannot load an XDP program on a machine with
more than 96 CPUs, due to limited hardware TX queues. E.g. virtio_net
is hard to configure as it requires manually increasing the
queues. E.g. tun driver chooses to use a per XDP frame producer lock
modulo smp_processor_id over avail queues.
I'm considered adding 'flags' to ndo_xdp_xmit, but it's not part of
this patchset. This will be a followup patchset, once we know if this
will be needed (e.g. for non-map xdp_redirect flush-flag, and if
AF_XDP chooses to use ndo_xdp_xmit for TX).
---
V5: Fixed up issues spotted by Daniel and John
V4: Splitout the patches from 4 to 8 patches. I cannot split the
driver changes from the NDO change, but I've tried to isolated the NDO
change together with the driver change as much as possible.
====================
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'drivers/net/ethernet/intel/ixgbe/ixgbe_main.c')
-rw-r--r-- | drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 21 |
1 files changed, 15 insertions, 6 deletions
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c index 6652b201df5b..9645619f7729 100644 --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c @@ -10017,11 +10017,13 @@ static int ixgbe_xdp(struct net_device *dev, struct netdev_bpf *xdp) } } -static int ixgbe_xdp_xmit(struct net_device *dev, struct xdp_frame *xdpf) +static int ixgbe_xdp_xmit(struct net_device *dev, int n, + struct xdp_frame **frames) { struct ixgbe_adapter *adapter = netdev_priv(dev); struct ixgbe_ring *ring; - int err; + int drops = 0; + int i; if (unlikely(test_bit(__IXGBE_DOWN, &adapter->state))) return -ENETDOWN; @@ -10033,11 +10035,18 @@ static int ixgbe_xdp_xmit(struct net_device *dev, struct xdp_frame *xdpf) if (unlikely(!ring)) return -ENXIO; - err = ixgbe_xmit_xdp_ring(adapter, xdpf); - if (err != IXGBE_XDP_TX) - return -ENOSPC; + for (i = 0; i < n; i++) { + struct xdp_frame *xdpf = frames[i]; + int err; - return 0; + err = ixgbe_xmit_xdp_ring(adapter, xdpf); + if (err != IXGBE_XDP_TX) { + xdp_return_frame_rx_napi(xdpf); + drops++; + } + } + + return n - drops; } static void ixgbe_xdp_flush(struct net_device *dev) |