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Message-Id: <20190121163356.31332-1-bjorn.topel@gmail.com> Date: Mon, 21 Jan 2019 17:33:56 +0100 From: bjorn.topel@...il.com To: intel-wired-lan@...ts.osuosl.org Cc: Björn Töpel <bjorn.topel@...el.com>, brouer@...hat.com, magnus.karlsson@...el.com, magnus.karlsson@...il.com, netdev@...r.kernel.org Subject: [PATCH] i40e: replace switch-statement with if-clause From: Björn Töpel <bjorn.topel@...el.com> GCC will generate jump tables for switch-statements with more than 5 case statements. An entry into the jump table is an indirect call, which means that for CONFIG_RETPOLINE builds, this is rather expensive. This commit replaces the switch-statement that acts on the XDP program result with an if-clause. The if-clause was also refactored into a common function that can be used by AF_XDP zero-copy and non-zero-copy code. Performance prior this patch: $ sudo ./xdp_rxq_info --dev enp134s0f0 --action XDP_DROP Running XDP on dev:enp134s0f0 (ifindex:7) action:XDP_DROP options:no_touch XDP stats CPU pps issue-pps XDP-RX CPU 20 18983018 0 XDP-RX CPU total 18983018 RXQ stats RXQ:CPU pps issue-pps rx_queue_index 20:20 18983012 0 rx_queue_index 20:sum 18983012 $ sudo ./xdpsock -i enp134s0f0 -q 20 -n 2 -z -r sock0@...134s0f0:20 rxdrop pps pkts 2.00 rx 14,641,496 144,751,092 tx 0 0 And after: $ sudo ./xdp_rxq_info --dev enp134s0f0 --action XDP_DROP Running XDP on dev:enp134s0f0 (ifindex:7) action:XDP_DROP options:no_touch XDP stats CPU pps issue-pps XDP-RX CPU 20 24000986 0 XDP-RX CPU total 24000986 RXQ stats RXQ:CPU pps issue-pps rx_queue_index 20:20 24000985 0 rx_queue_index 20:sum 24000985 +26% $ sudo ./xdpsock -i enp134s0f0 -q 20 -n 2 -z -r sock0@...134s0f0:20 rxdrop pps pkts 2.00 rx 17,623,578 163,503,263 tx 0 0 +20% Signed-off-by: Björn Töpel <bjorn.topel@...el.com> --- drivers/net/ethernet/intel/i40e/i40e_txrx.c | 31 ++++--------------- .../ethernet/intel/i40e/i40e_txrx_common.h | 27 ++++++++++++++++ drivers/net/ethernet/intel/i40e/i40e_xsk.c | 24 ++------------ 3 files changed, 35 insertions(+), 47 deletions(-) diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c index a7e14e98889f..b339b7ee6380 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c +++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c @@ -2,7 +2,6 @@ /* Copyright(c) 2013 - 2018 Intel Corporation. */ #include <linux/prefetch.h> -#include <linux/bpf_trace.h> #include <net/xdp.h> #include "i40e.h" #include "i40e_trace.h" @@ -2195,41 +2194,23 @@ int i40e_xmit_xdp_tx_ring(struct xdp_buff *xdp, struct i40e_ring *xdp_ring) static struct sk_buff *i40e_run_xdp(struct i40e_ring *rx_ring, struct xdp_buff *xdp) { - int err, result = I40E_XDP_PASS; - struct i40e_ring *xdp_ring; struct bpf_prog *xdp_prog; + int result; u32 act; rcu_read_lock(); xdp_prog = READ_ONCE(rx_ring->xdp_prog); - if (!xdp_prog) + if (!xdp_prog) { + result = I40E_XDP_PASS; goto xdp_out; + } prefetchw(xdp->data_hard_start); /* xdp_frame write */ act = bpf_prog_run_xdp(xdp_prog, xdp); - switch (act) { - case XDP_PASS: - break; - case XDP_TX: - xdp_ring = rx_ring->vsi->xdp_rings[rx_ring->queue_index]; - result = i40e_xmit_xdp_tx_ring(xdp, xdp_ring); - break; - case XDP_REDIRECT: - err = xdp_do_redirect(rx_ring->netdev, xdp, xdp_prog); - result = !err ? I40E_XDP_REDIR : I40E_XDP_CONSUMED; - break; - default: - bpf_warn_invalid_xdp_action(act); - /* fall through */ - case XDP_ABORTED: - trace_xdp_exception(rx_ring->netdev, xdp_prog, act); - /* fall through -- handle aborts by dropping packet */ - case XDP_DROP: - result = I40E_XDP_CONSUMED; - break; - } + i40e_xdp_do_action(act, &result, rx_ring, xdp, xdp_prog); + xdp_out: rcu_read_unlock(); return ERR_PTR(-result); diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx_common.h b/drivers/net/ethernet/intel/i40e/i40e_txrx_common.h index 8af0e99c6c0d..8cc4d8365f9e 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_txrx_common.h +++ b/drivers/net/ethernet/intel/i40e/i40e_txrx_common.h @@ -4,6 +4,8 @@ #ifndef I40E_TXRX_COMMON_ #define I40E_TXRX_COMMON_ +#include <linux/bpf_trace.h> + void i40e_fd_handle_status(struct i40e_ring *rx_ring, union i40e_rx_desc *rx_desc, u8 prog_id); int i40e_xmit_xdp_tx_ring(struct xdp_buff *xdp, struct i40e_ring *xdp_ring); @@ -88,4 +90,29 @@ void i40e_xsk_clean_rx_ring(struct i40e_ring *rx_ring); void i40e_xsk_clean_tx_ring(struct i40e_ring *tx_ring); bool i40e_xsk_any_rx_ring_enabled(struct i40e_vsi *vsi); +static inline void i40e_xdp_do_action(u32 act, int *result, + struct i40e_ring *rx_ring, + struct xdp_buff *xdp, + struct bpf_prog *xdp_prog) +{ + struct i40e_ring *xdp_ring; + int err; + + if (act == XDP_TX) { + xdp_ring = rx_ring->vsi->xdp_rings[rx_ring->queue_index]; + *result = i40e_xmit_xdp_tx_ring(xdp, xdp_ring); + } else if (act == XDP_REDIRECT) { + err = xdp_do_redirect(rx_ring->netdev, xdp, xdp_prog); + *result = !err ? I40E_XDP_REDIR : I40E_XDP_CONSUMED; + } else if (act == XDP_PASS) { + *result = I40E_XDP_PASS; + } else if (act == XDP_DROP) { + *result = I40E_XDP_CONSUMED; + } else { + if (act != XDP_ABORTED) + bpf_warn_invalid_xdp_action(act); + trace_xdp_exception(rx_ring->netdev, xdp_prog, act); + *result = I40E_XDP_CONSUMED; + } +} #endif /* I40E_TXRX_COMMON_ */ diff --git a/drivers/net/ethernet/intel/i40e/i40e_xsk.c b/drivers/net/ethernet/intel/i40e/i40e_xsk.c index 870cf654e436..1ed56475ec78 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_xsk.c +++ b/drivers/net/ethernet/intel/i40e/i40e_xsk.c @@ -282,9 +282,8 @@ int i40e_xsk_umem_setup(struct i40e_vsi *vsi, struct xdp_umem *umem, **/ static int i40e_run_xdp_zc(struct i40e_ring *rx_ring, struct xdp_buff *xdp) { - int err, result = I40E_XDP_PASS; - struct i40e_ring *xdp_ring; struct bpf_prog *xdp_prog; + int result; u32 act; rcu_read_lock(); @@ -294,26 +293,7 @@ static int i40e_run_xdp_zc(struct i40e_ring *rx_ring, struct xdp_buff *xdp) xdp_prog = READ_ONCE(rx_ring->xdp_prog); act = bpf_prog_run_xdp(xdp_prog, xdp); xdp->handle += xdp->data - xdp->data_hard_start; - switch (act) { - case XDP_PASS: - break; - case XDP_TX: - xdp_ring = rx_ring->vsi->xdp_rings[rx_ring->queue_index]; - result = i40e_xmit_xdp_tx_ring(xdp, xdp_ring); - break; - case XDP_REDIRECT: - err = xdp_do_redirect(rx_ring->netdev, xdp, xdp_prog); - result = !err ? I40E_XDP_REDIR : I40E_XDP_CONSUMED; - break; - default: - bpf_warn_invalid_xdp_action(act); - case XDP_ABORTED: - trace_xdp_exception(rx_ring->netdev, xdp_prog, act); - /* fallthrough -- handle aborts by dropping packet */ - case XDP_DROP: - result = I40E_XDP_CONSUMED; - break; - } + i40e_xdp_do_action(act, &result, rx_ring, xdp, xdp_prog); rcu_read_unlock(); return result; } -- 2.19.1
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