Fix rdmap message to be splited into two segments on receiver #45
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I'm not convinced that this is the correct fix. The mtu value that this function is using should already take the header length into account. |
ZiYang-oyxy
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【BUG DESCRIPTION】
Testcase `ib_write_lat -d urdma_0 -i 1 -x 0 -R -n 5 -s 976` will hang if
run with 82599 NIC.
On the receiver, `ddp_place_tagged_data` can only handle one mbuf
segment, but the rdmap message will be splited into two segments by
the 82599 port.
Dump tx mbuf on sender:
```txt
USER1: <dev=0 qp=2> [TX]
dump mbuf at 0x7002e7ecd800, iova=1d9d8cd8c0, buf_len=1654
pkt_len=1042, ol_flags=f0000000000000, nb_segs=2, in_port=65535
segment at 0x7002e7ecd800, data=0x7002e7ecd916, data_len=52
Dump data at [0x7002e7ecd916], len=52
00000000: 70 10 6F AE CD B5 70 10 6F AE CD 9D 08 00 45 00 | p.o...p.o.....E.
00000010: 04 04 00 00 00 00 40 11 00 00 C0 A7 01 03 C0 A7 | ......@.........
00000020: 01 04 F8 44 AF DD 03 F0 87 57 00 00 00 01 00 00 | ...D.....W......
00000030: 00 00 00 00 | | | | | | | | | | | | | ....
segment at 0x7002e7ecdfc0, data=0x7002e7ecd172, data_len=990
Dump data at [0x7002e7ecd172], len=990
00000000: C1 40 00 65 49 DD 00 00 00 00 00 69 44 00 00 00 | .@.eI......iD...
00000010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ................
00000020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ................
.
.
.
000003B0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ................
000003C0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ................
000003D0: 00 00 00 00 00 00 00 00 00 00 00 00 00 01 | | | ..............
```
Dump rx mbuf on receiver:
```txt
USER1: <dev=0 qp=2> [RX]
dump mbuf at 0x7002e9004500, iova=1f2d204580, buf_len=1654
pkt_len=1042, ol_flags=180, nb_segs=2, in_port=0
segment at 0x7002e9004500, data=0x7002e9004600, data_len=1024
Dump data at [0x7002e9004600], len=1024
00000000: 70 10 6F AE CD B5 70 10 6F AE CD 9D 08 00 45 00 | p.o...p.o.....E.
00000010: 04 04 00 00 00 00 40 11 F3 93 C0 A7 01 03 C0 A7 | ......@.........
00000020: 01 04 F8 44 AF DD 03 F0 7C A7 00 00 00 01 00 00 | ...D....|.......
00000030: 00 00 00 00 C1 40 00 65 49 DD 00 00 00 00 00 69 | .....@.eI......i
00000040: 44 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | D...............
00000050: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ................
.
.
.
000003D0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ................
000003E0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ................
000003F0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ................
segment at 0x7002e9004c40, data=0x7002e9004d40, data_len=18
Dump data at [0x7002e9004d40], len=18
00000000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ................
00000010: 00 01 | | | | | | | | | | | | | | | ..
```
【REASON】
The `mbuf_size` will less than 2K if the MTU is 1500, than the ixgbe PMD
will set the rx buffer to 1KB. Refer to the code below:
```c
ixgbe_dev_rx_init(struct rte_eth_dev *dev)
{
...
/*
* Configure the RX buffer size in the BSIZEPACKET field of
* the SRRCTL register of the queue.
* The value is in 1 KB resolution. Valid values can be from
* 1 KB to 16 KB.
*/
buf_size = (uint16_t)(rte_pktmbuf_data_room_size(rxq->mb_pool) -
RTE_PKTMBUF_HEADROOM);
srrctl |= ((buf_size >> IXGBE_SRRCTL_BSIZEPKT_SHIFT) &
IXGBE_SRRCTL_BSIZEPKT_MASK);
IXGBE_WRITE_REG(hw, IXGBE_SRRCTL(rxq->reg_idx), srrctl);
...
}
```
【FIX】
Refer to the comment of `RTE_MBUF_DEFAULT_BUF_SIZE`, it's the recommended
minimal buffer length.
```c
/**
* Some NICs need at least 2KB buffer to RX standard Ethernet frame without
* splitting it into multiple segments.
* So, for mbufs that planned to be involved into RX/TX, the recommended
* minimal buffer length is 2KB + RTE_PKTMBUF_HEADROOM.
*/
(RTE_MBUF_DEFAULT_DATAROOM + RTE_PKTMBUF_HEADROOM)
```
Signed-off-by: ziyang <hh123okbb@gmail.com>
ZiYang-oyxy
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ZiYang-oyxy
changed the title
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The first commit is not correct, I have pushed a new commit to overwrite the old one |
patrickmacarthur
approved these changes
Aug 24, 2018
|
@BernardMetzler @PepperJo Can you one of you give your approval on this PR? |
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Signed-off-by: ziyang hh123okbb@gmail.com