Date: Mon, 2 Jan 2017 12:09:15 +0100 From: Ben RUBSON <ben.rubson@gmail.com> To: "freebsd-net@freebsd.org" <freebsd-net@freebsd.org> Cc: Hans Petter Selasky <hanss@mellanox.com>, Yuval Bason <yuvalba@mellanox.com>, Meny Yossefi <menyy@mellanox.com> Subject: Re: iSCSI failing, MLX rx_ring errors ? Message-ID: <613AFD8E-72B2-4E3F-9C70-1D1E43109B8A@gmail.com> In-Reply-To: <DB3PR05MB089A5789A0A619FA8B7CA36C36C0@DB3PR05MB089.eurprd05.prod.outlook.com> References: <486A6DA0-54C8-40DF-8437-F6E382DA01A8@gmail.com> <6a31ef00-5f7a-d36e-d5e6-0414e8b813c7@selasky.org> <DB3PR05MB089A5789A0A619FA8B7CA36C36C0@DB3PR05MB089.eurprd05.prod.outlook.com>
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Hi Meny, Thank you very much for your feedback. I think you are right, this could be a mbufs issue. Here are some more numbers : # vmstat -z | grep -v "0, 0$" ITEM SIZE LIMIT USED FREE REQ = FAIL SLEEP 4 Bucket: 32, 0, 2673, 28327, 88449799, = 17317, 0 8 Bucket: 64, 0, 449, 15609, 13926386, = 4871, 0 12 Bucket: 96, 0, 335, 5323, 10293892, = 142872, 0 16 Bucket: 128, 0, 533, 6070, 7618615, = 472647, 0 32 Bucket: 256, 0, 8317, 22133, 36020376, = 563479, 0 64 Bucket: 512, 0, 1238, 3298, 20138111, = 11430742, 0 128 Bucket: 1024, 0, 1865, 2963, 21162182, = 158752, 0 256 Bucket: 2048, 0, 1626, 450, 80253784, = 4890164, 0 mbuf_jumbo_9k: 9216, 603712, 16400, 8744, 4128521064, = 2661, 0 # netstat -m 32801/18814/51615 mbufs in use (current/cache/total) 16400/9810/26210/4075058 mbuf clusters in use (current/cache/total/max) 16400/9659 mbuf+clusters out of packet secondary zone in use = (current/cache) 0/8647/8647/2037529 4k (page size) jumbo clusters in use = (current/cache/total/max) 16400/8744/25144/603712 9k jumbo clusters in use = (current/cache/total/max) 0/0/0/339588 16k jumbo clusters in use (current/cache/total/max) 188600K/137607K/326207K bytes allocated to network (current/cache/total) 0/0/0 requests for mbufs denied (mbufs/clusters/mbuf+clusters) 0/0/0 requests for mbufs delayed (mbufs/clusters/mbuf+clusters) 0/0/0 requests for jumbo clusters delayed (4k/9k/16k) 0/2661/0 requests for jumbo clusters denied (4k/9k/16k) 0 sendfile syscalls 0 sendfile syscalls completed without I/O request 0 requests for I/O initiated by sendfile 0 pages read by sendfile as part of a request 0 pages were valid at time of a sendfile request 0 pages were requested for read ahead by applications 0 pages were read ahead by sendfile 0 times sendfile encountered an already busy page 0 requests for sfbufs denied 0 requests for sfbufs delayed I did not perform any mbufs tuning, numbers above are from FreeBSD = itself. This server has 64GB of memory. It has a ZFS pool for which I limit ARC memory impact with : vfs.zfs.arc_max=3D64424509440 #60G The only thing I did is some TCP tuning to improve throughput over = high-latency long-distance private links : kern.ipc.maxsockbuf=3D7372800 net.inet.tcp.sendbuf_max=3D6553600 net.inet.tcp.recvbuf_max=3D6553600 net.inet.tcp.sendspace=3D65536 net.inet.tcp.recvspace=3D65536 net.inet.tcp.sendbuf_inc=3D65536 net.inet.tcp.recvbuf_inc=3D65536 net.inet.tcp.cc.algorithm=3Dhtcp Here are some graphs of memory & ARC usage when issue occurs. Crosshair (vertical red line) is at the timestamp where I get iSCSI = disconnections. https://postimg.org/gallery/1kkekrc4e/ What is strange is that each time issue occurs there is around 1GB of = free memory. So FreeBSD should still be able to allocate some more mbufs ? Unfortunately I do not have graphs about mbufs. What should I ideally do ? Thank you again, Best regards, Ben > On 01 Jan 2017, at 09:16, Meny Yossefi <menyy@mellanox.com> wrote: >=20 > Hi Ben,=20 > =20 > Those are not HW errors, note that: > =20 > hw.mlxen1.stat.rx_dropped: 0 > hw.mlxen1.stat.rx_errors: 0 > =20 > It seems to be triggered when you are failing to allocate a = replacement buffer. > Any chance you ran out of mbufs in the system? > =20 > en_rx.c: > =20 > mlx4_en_process_rx_cq(): > =20 > mb =3D mlx4_en_rx_mb(priv, rx_desc, mb_list, length); > if (!mb) { > ring->errors++; > goto next; > } > =20 > mlx4_en_rx_mb() =C3=A0 mlx4_en_complete_rx_desc(): > =20 > /* Allocate a replacement page */ > if (mlx4_en_alloc_buf(priv, rx_desc, mb_list, nr)) > goto fail; > =20 > -Meny
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