diff options
| author | Jiri Benc | 2012-10-25 20:12:05 +0200 |
|---|---|---|
| committer | Jeff Kirsher | 2012-10-30 07:34:30 +0100 |
| commit | f42df16756dbcaba7b50cb7bbb0833b65d3ae167 (patch) | |
| tree | dfa4acdb64cb7fcbbafc035dce69edbcffbf6ad7 /drivers/net/ethernet/intel/ixgbe/ixgbe_ptp.c | |
| parent | ixgbe: add/update descriptor maps in comments (diff) | |
| download | kernel-qcow2-linux-f42df16756dbcaba7b50cb7bbb0833b65d3ae167.tar.gz kernel-qcow2-linux-f42df16756dbcaba7b50cb7bbb0833b65d3ae167.tar.xz kernel-qcow2-linux-f42df16756dbcaba7b50cb7bbb0833b65d3ae167.zip | |
ixgbe: reduce PTP rx path overhead
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 ixgbe 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 <jbrouer@redhat.com>
Signed-off-by: Jiri Benc <jbenc@redhat.com>
Signed-off-by: Andy Gospodarek <gospo@redhat.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Diffstat (limited to 'drivers/net/ethernet/intel/ixgbe/ixgbe_ptp.c')
| -rw-r--r-- | 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 5e71ddbb3414..842ba15550a5 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; /* |