> On 03 Jan 2017, at 07:27, Meny Yossefi <me...@mellanox.com> wrote: > >> From: owner-freebsd-net@freebsd.orgOn Behalf OfBen RUBSON >> Sent: Monday, January 2, 2017 11:09:15 AM (UTC+00:00) Monrovia, Reykjavik >> To: freebsd-net@freebsd.org >> Cc: Meny Yossefi; Yuval Bason; Hans Petter Selasky >> Subject: Re: iSCSI failing, MLX rx_ring errors ? >> >> 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=64424509440 #60G >> >> The only thing I did is some TCP tuning to improve throughput over >> high-latency long-distance private links : >> kern.ipc.maxsockbuf=7372800 >> net.inet.tcp.sendbuf_max=6553600 >> net.inet.tcp.recvbuf_max=6553600 >> net.inet.tcp.sendspace=65536 >> net.inet.tcp.recvspace=65536 >> net.inet.tcp.sendbuf_inc=65536 >> net.inet.tcp.recvbuf_inc=65536 >> net.inet.tcp.cc.algorithm=htcp >> >> 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 ? > > Have you tried increasing the mbufs limit? > (sysctl) kern.ipc.nmbufs (Maximum number of mbufs allowed)
Thank you for your suggestion Meny. No I did not try this yet. However, from the numbers above (and below), I think I should increase kern.ipc.nmbjumbo9 instead ? # vmstat -z | grep -E "ITEM|mbuf" ITEM SIZE LIMIT USED FREE REQ FAIL SLEEP mbuf_packet: 256, 26080395, 16400, 10418, 572292683, 0, 0 mbuf: 256, 26080395, 16402, 40525, 20955366061, 0, 0 mbuf_cluster: 2048, 4075060, 26818, 148, 907005, 0, 0 mbuf_jumbo_page: 4096, 2037529, 0, 34262, 5194563127, 0, 0 mbuf_jumbo_9k: 9216, 603712, 16400, 12867, 4362104082, 2676, 0 mbuf_jumbo_16k: 16384, 339588, 0, 0, 0, 0, 0 # sysctl kern.ipc | grep mb kern.ipc.nmbufs: 26080380 kern.ipc.nmbclusters: 4075058 kern.ipc.nmbjumbop: 2037529 kern.ipc.nmbjumbo9: 1811136 kern.ipc.nmbjumbo16: 1358352 kern.ipc.maxmbufmem: 33382879232 // note that I don't understand the difference between vmstat and sysctl nmbjumbo9 / nmbjumbo16 values. // the first one is /3 (1811136/3=603712) the second one is /4 (1358352/4=339588). Strange. // interesting post from Robert Watson which helped me understanding some numbers : // https://lists.freebsd.org/pipermail/freebsd-net/2008-December/020350.html _______________________________________________ freebsd-net@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to "freebsd-net-unsubscr...@freebsd.org"
