Hw timestamping code caused performance regression in ixgbe driver when the timestamping is not enabled. The culprit is IXGBE_READ_REG call in the rx path which is executed for every received skb. This call is not needed when the timestamping is disabled or for non-ptp packets.
netperf results: The ixge side of the connection was acting as a server, the netperf command line on the other side was: netperf -H 192.168.1.23 -T0,0 -t UDP_STREAM -l 20 The values below mean throughput as reported by netperf (local/remote), for 3 runs, with timestamping not enabled. 3.7.0-rc1+ with CONFIG_IXGBE_PTP off: 5373.83 / 3329.32 5721.88 / 3033.89 5653.42 / 3112.38 3.7.0-rc1+ with CONFIG_IXGBE_PTP on: 5233.64 / 1226.85 5448.67 / 1039.32 5421.36 / 1095.66 Patched 3.7.0-rc1+ with CONFIG_IXGBE_PTP on: 5594.72 / 2942.53 5428.95 / 3110.16 5343.56 / 3200.48 Reported-by: Jesper Brouer <[email protected]> Signed-off-by: Jiri Benc <[email protected]> Signed-off-by: Andy Gospodarek <[email protected]> --- drivers/net/ethernet/intel/ixgbe/ixgbe_ptp.c | 6 ++++-- 1 files changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_ptp.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_ptp.c index 5e71ddb..842ba15 100644 --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_ptp.c +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_ptp.c @@ -554,12 +554,14 @@ void ixgbe_ptp_rx_hwtstamp(struct ixgbe_q_vector *q_vector, adapter = q_vector->adapter; hw = &adapter->hw; + if (likely(!ixgbe_ptp_match(skb, adapter->rx_hwtstamp_filter))) + return; + tsyncrxctl = IXGBE_READ_REG(hw, IXGBE_TSYNCRXCTL); /* Check if we have a valid timestamp and make sure the skb should * have been timestamped */ - if (likely(!(tsyncrxctl & IXGBE_TSYNCRXCTL_VALID) || - !ixgbe_ptp_match(skb, adapter->rx_hwtstamp_filter))) + if (!(tsyncrxctl & IXGBE_TSYNCRXCTL_VALID)) return; /* -- 1.7.6.5 ------------------------------------------------------------------------------ Everyone hates slow websites. So do we. Make your web apps faster with AppDynamics Download AppDynamics Lite for free today: http://p.sf.net/sfu/appdyn_sfd2d_oct _______________________________________________ E1000-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/e1000-devel To learn more about Intel® Ethernet, visit http://communities.intel.com/community/wired
