Messages in this thread | | | Date | Mon, 8 Apr 2024 14:31:26 +0300 | Subject | Re: [Intel-wired-lan] [PATCH iwl-next, v4 1/1] igc: Add Tx hardware timestamp request for AF_XDP zero-copy packet | From | "naamax.meir" <> |
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On 3/25/2024 04:09, Song Yoong Siang wrote: > This patch adds support to per-packet Tx hardware timestamp request to > AF_XDP zero-copy packet via XDP Tx metadata framework. Please note that > user needs to enable Tx HW timestamp capability via igc_ioctl() with > SIOCSHWTSTAMP cmd before sending xsk Tx hardware timestamp request. > > Same as implementation in RX timestamp XDP hints kfunc metadata, Timer 0 > (adjustable clock) is used in xsk Tx hardware timestamp. i225/i226 have > four sets of timestamping registers. *skb and *xsk_tx_buffer pointers > are used to indicate whether the timestamping register is already occupied. > > Furthermore, a boolean variable named xsk_pending_ts is used to hold the > transmit completion until the tx hardware timestamp is ready. This is > because, for i225/i226, the timestamp notification event comes some time > after the transmit completion event. The driver will retrigger hardware irq > to clean the packet after retrieve the tx hardware timestamp. > > Besides, xsk_meta is added into struct igc_tx_timestamp_request as a hook > to the metadata location of the transmit packet. When the Tx timestamp > interrupt is fired, the interrupt handler will copy the value of Tx hwts > into metadata location via xsk_tx_metadata_complete(). > > This patch is tested with tools/testing/selftests/bpf/xdp_hw_metadata > on Intel ADL-S platform. Below are the test steps and results. > > Test Step 1: Run xdp_hw_metadata app > ./xdp_hw_metadata <iface> > /dev/shm/result.log > > Test Step 2: Enable Tx hardware timestamp > hwstamp_ctl -i <iface> -t 1 -r 1 > > Test Step 3: Run ptp4l and phc2sys for time synchronization > > Test Step 4: Generate UDP packets with 1ms interval for 10s > trafgen --dev <iface> '{eth(da=<addr>), udp(dp=9091)}' -t 1ms -n 10000 > > Test Step 5: Rerun Step 1-3 with 10s iperf3 as background traffic > > Test Step 6: Rerun Step 1-4 with 10s iperf3 as background traffic > > Based on iperf3 results below, the impact of holding tx completion to > throughput is not observable. > > Result of last UDP packet (no. 10000) in Step 4: > poll: 1 (0) skip=99 fail=0 redir=10000 > xsk_ring_cons__peek: 1 > 0x5640a37972d0: rx_desc[9999]->addr=f2110 addr=f2110 comp_addr=f2110 EoP > rx_hash: 0x2049BE1D with RSS type:0x1 > HW RX-time: 1679819246792971268 (sec:1679819246.7930) delta to User RX-time sec:0.0000 (14.990 usec) > XDP RX-time: 1679819246792981987 (sec:1679819246.7930) delta to User RX-time sec:0.0000 (4.271 usec) > No rx_vlan_tci or rx_vlan_proto, err=-95 > 0x5640a37972d0: ping-pong with csum=ab19 (want 315b) csum_start=34 csum_offset=6 > 0x5640a37972d0: complete tx idx=9999 addr=f010 > HW TX-complete-time: 1679819246793036971 (sec:1679819246.7930) delta to User TX-complete-time sec:0.0001 (77.656 usec) > XDP RX-time: 1679819246792981987 (sec:1679819246.7930) delta to User TX-complete-time sec:0.0001 (132.640 usec) > HW RX-time: 1679819246792971268 (sec:1679819246.7930) delta to HW TX-complete-time sec:0.0001 (65.703 usec) > 0x5640a37972d0: complete rx idx=10127 addr=f2110 > > Result of iperf3 without tx hwts request in step 5: > [ ID] Interval Transfer Bitrate Retr > [ 5] 0.00-10.00 sec 2.74 GBytes 2.36 Gbits/sec 0 sender > [ 5] 0.00-10.05 sec 2.74 GBytes 2.34 Gbits/sec receiver > > Result of iperf3 running parallel with trafgen command in step 6: > [ ID] Interval Transfer Bitrate Retr > [ 5] 0.00-10.00 sec 2.74 GBytes 2.36 Gbits/sec 0 sender > [ 5] 0.00-10.04 sec 2.74 GBytes 2.34 Gbits/sec receiver > > Co-developed-by: Lai Peter Jun Ann <jun.ann.lai@intel.com> > Signed-off-by: Lai Peter Jun Ann <jun.ann.lai@intel.com> > Signed-off-by: Song Yoong Siang <yoong.siang.song@intel.com> > Acked-by: John Fastabend <john.fastabend@gmail.com> > --- > V1: https://patchwork.kernel.org/project/netdevbpf/patch/20231215162158.951925-1-yoong.siang.song@intel.com/ > V2: https://patchwork.kernel.org/project/netdevbpf/cover/20240301162348.898619-1-yoong.siang.song@intel.com/ > V3: https://patchwork.kernel.org/project/netdevbpf/cover/20240303083225.1184165-1-yoong.siang.song@intel.com/ > > changelog: > V1 -> V2 > - In struct igc_tx_timestamp_request, keep a pointer to igc_tx_buffer, > instead of pointing xsk_pending_ts (Vinicius). > - In struct igc_tx_timestamp_request, introduce buffer_type to indicate > whether skb or igc_tx_buffer pointer should be use (Vinicius). > - In struct igc_metadata_request, remove igc_adapter pointer (Vinicius). > - When request tx hwts, copy the value of cmd_type, instead of using > pointer (Vinicius). > - For boolean variable, use true and false, instead of 1 and 0 (Vinicius). > - In igc_xsk_request_timestamp(), make an early return if none of the 4 ts > registers is available (Vinicius). > - Create helper functions to clear tx buffer and skb for tstamp (John). > - Perform throughput test with mix traffic (Vinicius & John). > V2 -> V3 > - Improve tstamp reg searching loop for better readability (John). > - In igc_ptp_free_tx_buffer(), add comment to inform user that > tstamp->xsk_tx_buffer and tstamp->skb are in union (John). > V3 -> V4 > - Add protection with xp_tx_metadata_enabled (Kurt & Maciej). > --- > --- > drivers/net/ethernet/intel/igc/igc.h | 71 ++++++++------ > drivers/net/ethernet/intel/igc/igc_main.c | 113 ++++++++++++++++++++-- > drivers/net/ethernet/intel/igc/igc_ptp.c | 51 ++++++++-- > 3 files changed, 195 insertions(+), 40 deletions(-)
Tested-by: Naama Meir <naamax.meir@linux.intel.com>
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