Hi,
I tried to use gdb to print the rx descriptor, and it turned out that only the
rxd for the last segment has correct l2tag1 value.
Test step: ping xx.xx.xx.xx -s 2500, from a vlan interface with vlan id 1901,
MTU 9000. (this will sends 1 packet, and needs two mbuf segments to receive,
length of 1st mbuf segment is 2176(mbuf size of my dpdk application), length of
2nd mbuf segment is 366)
Rx descriptor printed with gdb:
Breakpoint 2 at 0x7ffff5efa4bb: file
/usr/src/debug/dpdk-18.11.1-2.nok6.wf31.x86_64/package/dpdk/dpdk-18.11/drivers/net/i40e/i40e_rxtx_vec_avx2.c,
line 496.
(gdb) print *(rxq->rx_ring + rxq->rx_tail+1)
$4 = {read = {pkt_addr = 14858615587319906304, hdr_addr = 598164390293517,
rsvd1 = 0,
rsvd2 = 0}, wb = {qword0 = {lo_dword = {mirr_fcoe = {mirroring_status = 0,
fcoe_ctx_id = 0}, l2tag1 = 73}, hi_dword = {rss = 3459541031,
fcoe_param = 3459541031, fd_id = 3459541031}}, qword1 = {
status_error_len = 598164390293517}, qword2 = {ext_status = 0, rsvd = 0,
l2tag2_1 = 0, l2tag2_2 = 0}, qword3 = {lo_dword = {flex_bytes_lo = 0,
pe_status = 0}, hi_dword = {flex_bytes_hi = 0, fd_id = 0}}}}
(gdb) print *(rxq->rx_ring + rxq->rx_tail+2)
$5 = {read = {pkt_addr = 14858615587439706112, hdr_addr = 100635378724879,
rsvd1 = 0,
rsvd2 = 0}, wb = {qword0 = {lo_dword = {mirr_fcoe = {mirroring_status = 0,
fcoe_ctx_id = 0}, l2tag1 = 1901}, hi_dword = {rss = 3459541031,
fcoe_param = 3459541031, fd_id = 3459541031}}, qword1 = {
status_error_len = 100635378724879}, qword2 = {ext_status = 0, rsvd = 0,
l2tag2_1 = 0, l2tag2_2 = 0}, qword3 = {lo_dword = {flex_bytes_lo = 0,
pe_status = 0}, hi_dword = {flex_bytes_hi = 0, fd_id = 0}}}}
With formula: length = (qword1 & I40E_RXD_QW1_LENGTH_PBUF_MASK) >>
I40E_RXD_QW1_LENGTH_PBUF_SHIFT; (qword1 is status_error_len in gdb printout)
I can get length of first segment(rxq->rx_ring + rxq->rx_tail+1) is 2176, and length
of second segment(rxq->rx_ring + rxq->rx_tail+2) is 366, which proves they are the
mbuf segments to receive.
However we can see the l2tag1 of first segment is 73(invalid), l2tag1 of second
segment is 1901(valid).
It means either HW should be modified to fill l2tag1 correctly for each every
segment, or _recv_raw_pkts_vec_avx2 should be modified to read l2tag1 of last
segment?
PS: it seems i40e_recv_scattered_pkts use the l2tag1 of last rxd (to set vlan
tci of first segment), don't know it is by accident(convenience) or by purpose.
Do you agree on my analysis?
If my analysis is correct, is it possible for you to help make a sw patch,
because I'm not familiar with this vec avx code.
Best regards
Yan Xiaoping
-----Original Message-----
From: Jeff Guo <jia....@intel.com>
Sent: 2020年5月19日 15:00
To: Yan, Xiaoping (NSB - CN/Hangzhou) <xiaoping....@nokia-sbell.com>;
beilei.x...@intel.com
Cc: dev@dpdk.org; Olivier Matz <olivier.m...@6wind.com>
Subject: Re: [dpdk-dev] incorrect vlan_tci in rte mbuf
hi, xiaoping
On 5/18/2020 4:31 PM, Yan, Xiaoping (NSB - CN/Hangzhou) wrote:
Hi Beilei & Jia,
I got your name from the MAINTAINERS for Intel i40e.
Could you help to have a look at the issue, described in my previous mail?
Thank you.
Best regards
Yan Xiaoping
-----Original Message-----
From: Olivier Matz <olivier.m...@6wind.com>
Sent: 2020年5月18日 15:24
To: Yan, Xiaoping (NSB - CN/Hangzhou) <xiaoping....@nokia-sbell.com>
Cc: dev@dpdk.org
Subject: Re: [dpdk-dev] incorrect vlan_tci in rte mbuf
Hi,
On Fri, May 15, 2020 at 11:12:27AM +0000, Yan, Xiaoping (NSB - CN/Hangzhou)
wrote:
Hi,
I'm using i40e vf, dpdk 18.11, x86_64 CPU (rx function in use is
i40e_recv_scattered_pkts_vec_avx2)
When enable hw vlan strip:
* If packet fit in one mbuf segment, the vlan_tci field is correct
* If packets are stored in several mbuf segment, the vlan_tci of last
segment is correct, vlan_tci of other segments are invalid
It seems i40e_recv_scattered_pkts has correctly set the vlan_tci, by
calling i40e_rxd_to_vlan_tci(first_seg, &rxd);
Is this a bug in i40e_recv_scattered_pkts_vec_avx2?
(I didn't find setting vlan_tci for first segment, but it's a bit
difficult for me to understand codes in
i40e_recv_scattered_pkts_vec_avx2, so I'm not quite sure) I checked
the latest dpdk version 20.02
http://lxr.dpdk.org/dpdk/latest/source/drivers/net/i40e/i40e_rxtx_vec
_
avx2.c#L791
But seems no change for this.
Any comment please?
[...]
I don't know about the i40e driver, but I can confirm that the vlan tci flag
should be in the first segment, and not in the next ones.
I suggest to CC i40e driver maintainers.
Regards,
Olivier
On one hand, as Olivier said that vlan tci flag should be in the first segment, and on
the other hands, vlan_tci do process in "_recv_raw_pkts_vec_avx2" when use 256
instinct
to process the descriptor with mbuf, you could check how to process the
vlan_flags_shuf and blend it into the mbuf.
