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Date:      Sat, 9 Aug 2014 21:49:03 +0200
From:      Michael Tuexen <Michael.Tuexen@lurchi.franken.de>
To:        "Eggert, Lars" <lars@netapp.com>
Cc:        "freebsd-net@freebsd.org" <freebsd-net@freebsd.org>, Niu Zhixiong <kaiaixi@gmail.com>, Bill Yuan <bycn82@gmail.com>
Subject:   Re: A problem on TCP in High RTT Environment.
Message-ID:  <E77F600E-CAFA-46B7-A950-700B5C3D0D71@lurchi.franken.de>
In-Reply-To: <A6B17C10-F72F-4182-9A1C-FD787448E068@netapp.com>
References:  <CAOENNMA_CiBDJc0kchzUbTcf_JBwTJPF=PdBAUB6FPo-KzYkeQ@mail.gmail.com> <A6B17C10-F72F-4182-9A1C-FD787448E068@netapp.com>

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On 09 Aug 2014, at 11:51, Eggert, Lars <lars@netapp.com> wrote:

> At 400ms at @ 20Mbps, your are probably receive window limited. Bump =
net.inet.tcp.recvspace. (Your net.inet.sctp.recvspace is much larger, =
which probably explains the performance difference.)
The program he is using is netperfmeter and I think it sets the =
send/recv buffer to 2MB...

Best regards
Michael
>=20
> On 2014-8-8, at 14:34, Niu Zhixiong <kaiaixi@gmail.com> wrote:
>=20
>> Dear all,
>>=20
>> Last month, I send problems related to FTP/TCP in a high RTT =
environment.
>> After that, I setup a simulation environment(Dummynet) to test TCP =
and SCTP
>> in high delay environment. After finishing the test, I can see TCP is
>> always slower than SCTP. But, I think it is not possible. (Plz see =
the
>> figure in the attachment). When the delay is 200ms(means RTT=3D400ms).
>> Besides, the TCP is extremely slow.
>>=20
>> ALL BW=3D20Mbps, DELAY=3D 0 ~ 200MS, Packet LOSS =3D 0 (by dummynet)
>>=20
>> This is my parameters:
>> FreeBSD vfreetest0 10.0-RELEASE FreeBSD 10.0-RELEASE #0: Thu Aug  7
>> 11:04:15 HKT 2014
>>=20
>> sysctl net.inet.tcp
>> net.inet.tcp.rfc1323: 1
>> net.inet.tcp.mssdflt: 536
>> net.inet.tcp.keepidle: 7200000
>> net.inet.tcp.keepintvl: 75000
>> net.inet.tcp.sendspace: 32768
>> net.inet.tcp.recvspace: 65536
>> net.inet.tcp.keepinit: 75000
>> net.inet.tcp.delacktime: 100
>> net.inet.tcp.v6mssdflt: 1220
>> net.inet.tcp.cc.algorithm: newreno
>> net.inet.tcp.cc.available: newreno
>> net.inet.tcp.hostcache.cachelimit: 15360
>> net.inet.tcp.hostcache.hashsize: 512
>> net.inet.tcp.hostcache.bucketlimit: 30
>> net.inet.tcp.hostcache.count: 0
>> net.inet.tcp.hostcache.expire: 3600
>> net.inet.tcp.hostcache.prune: 300
>> net.inet.tcp.hostcache.purge: 0
>> net.inet.tcp.log_in_vain: 0
>> net.inet.tcp.blackhole: 0
>> net.inet.tcp.delayed_ack: 1
>> net.inet.tcp.drop_synfin: 0
>> net.inet.tcp.rfc3042: 1
>> net.inet.tcp.rfc3390: 1
>> net.inet.tcp.experimental.initcwnd10: 1
>> net.inet.tcp.rfc3465: 1
>> net.inet.tcp.abc_l_var: 2
>> net.inet.tcp.ecn.enable: 0
>> net.inet.tcp.ecn.maxretries: 1
>> net.inet.tcp.insecure_rst: 0
>> net.inet.tcp.recvbuf_auto: 0
>> net.inet.tcp.recvbuf_inc: 16384
>> net.inet.tcp.recvbuf_max: 2097152
>> net.inet.tcp.path_mtu_discovery: 1
>> net.inet.tcp.tso: 1
>> net.inet.tcp.sendbuf_auto: 0
>> net.inet.tcp.sendbuf_inc: 8192
>> net.inet.tcp.sendbuf_max: 2097152
>> net.inet.tcp.reass.maxsegments: 15900
>> net.inet.tcp.reass.cursegments: 0
>> net.inet.tcp.reass.overflows: 0
>> net.inet.tcp.sack.enable: 1
>> net.inet.tcp.sack.maxholes: 128
>> net.inet.tcp.sack.globalmaxholes: 65536
>> net.inet.tcp.sack.globalholes: 0
>> net.inet.tcp.minmss: 216
>> net.inet.tcp.log_debug: 0
>> net.inet.tcp.tcbhashsize: 32768
>> net.inet.tcp.do_tcpdrain: 1
>> net.inet.tcp.pcbcount: 4
>> net.inet.tcp.icmp_may_rst: 1
>> net.inet.tcp.isn_reseed_interval: 0
>> net.inet.tcp.soreceive_stream: 0
>> net.inet.tcp.syncookies: 1
>> net.inet.tcp.syncookies_only: 0
>> net.inet.tcp.syncache.bucketlimit: 30
>> net.inet.tcp.syncache.cachelimit: 15375
>> net.inet.tcp.syncache.count: 0
>> net.inet.tcp.syncache.hashsize: 512
>> net.inet.tcp.syncache.rexmtlimit: 3
>> net.inet.tcp.syncache.rst_on_sock_fail: 1
>> net.inet.tcp.msl: 30000
>> net.inet.tcp.rexmit_min: 30
>> net.inet.tcp.rexmit_slop: 200
>> net.inet.tcp.always_keepalive: 1
>> net.inet.tcp.fast_finwait2_recycle: 0
>> net.inet.tcp.finwait2_timeout: 60000
>> net.inet.tcp.keepcnt: 8
>> net.inet.tcp.rexmit_drop_options: 0
>> net.inet.tcp.per_cpu_timers: 0
>> net.inet.tcp.timer_race: 0
>> net.inet.tcp.maxtcptw: 26070
>> net.inet.tcp.nolocaltimewait: 0
>>=20
>> kern.ipc.maxsockbuf: 4000000
>> kern.ipc.sockbuf_waste_factor: 8
>> kern.ipc.max_linkhdr: 16
>> kern.ipc.max_protohdr: 60
>> kern.ipc.max_hdr: 76
>> kern.ipc.max_datalen: 92
>> kern.ipc.maxmbufmem: 2073962496
>> kern.ipc.nmbclusters: 253170
>> kern.ipc.nmbjumbop: 126584
>> kern.ipc.nmbjumbo9: 112518
>> kern.ipc.nmbjumbo16: 84388
>> kern.ipc.nmbufs: 1620285
>> kern.ipc.maxpipekva: 66736128
>> kern.ipc.pipekva: 16384
>> kern.ipc.pipefragretry: 0
>> kern.ipc.pipeallocfail: 0
>> kern.ipc.piperesizefail: 0
>> kern.ipc.piperesizeallowed: 1
>> kern.ipc.msgmax: 16384
>> kern.ipc.msgmni: 40
>> kern.ipc.msgmnb: 2048
>> kern.ipc.msgtql: 40
>> kern.ipc.msgssz: 8
>> kern.ipc.msgseg: 2048
>> kern.ipc.semmni: 50
>> kern.ipc.semmns: 340
>> kern.ipc.semmnu: 150
>> kern.ipc.semmsl: 340
>> kern.ipc.semopm: 100
>> kern.ipc.semume: 50
>> kern.ipc.semusz: 632
>> kern.ipc.semvmx: 32767
>> kern.ipc.semaem: 16384
>> kern.ipc.shmmax: 536870912
>> kern.ipc.shmmin: 1
>> kern.ipc.shmmni: 192
>> kern.ipc.shmseg: 128
>> kern.ipc.shmall: 131072
>> kern.ipc.shm_use_phys: 0
>> kern.ipc.shm_allow_removed: 0
>> kern.ipc.soacceptqueue: 128
>> kern.ipc.numopensockets: 14
>> kern.ipc.maxsockets: 130350
>> kern.ipc.sendfile.readahead: 1
>>=20
>> sysctl net.inet.sctp
>> net.inet.sctp.sendspace: 2097152
>> net.inet.sctp.recvspace: 2097152
>> net.inet.sctp.auto_asconf: 1
>> net.inet.sctp.ecn_enable: 1
>> net.inet.sctp.strict_sacks: 1
>> net.inet.sctp.peer_chkoh: 256
>> net.inet.sctp.maxburst: 4
>> net.inet.sctp.fr_maxburst: 4
>> net.inet.sctp.maxchunks: 31646
>> net.inet.sctp.tcbhashsize: 1024
>> net.inet.sctp.pcbhashsize: 256
>> net.inet.sctp.min_split_point: 2904
>> net.inet.sctp.chunkscale: 10
>> net.inet.sctp.delayed_sack_time: 200
>> net.inet.sctp.sack_freq: 2
>> net.inet.sctp.sys_resource: 1000
>> net.inet.sctp.asoc_resource: 10
>> net.inet.sctp.heartbeat_interval: 30000
>> net.inet.sctp.pmtu_raise_time: 600
>> net.inet.sctp.shutdown_guard_time: 180
>> net.inet.sctp.secret_lifetime: 3600
>> net.inet.sctp.rto_max: 60000
>> net.inet.sctp.rto_min: 1000
>> net.inet.sctp.rto_initial: 3000
>> net.inet.sctp.init_rto_max: 60000
>> net.inet.sctp.valid_cookie_life: 60000
>> net.inet.sctp.init_rtx_max: 8
>> net.inet.sctp.assoc_rtx_max: 10
>> net.inet.sctp.path_rtx_max: 5
>> net.inet.sctp.path_pf_threshold: 65535
>> net.inet.sctp.add_more_on_output: 1452
>> net.inet.sctp.incoming_streams: 2048
>> net.inet.sctp.outgoing_streams: 10
>> net.inet.sctp.cmt_on_off: 0
>> net.inet.sctp.nr_sack_on_off: 0
>> net.inet.sctp.cmt_use_dac: 0
>> net.inet.sctp.cwnd_maxburst: 1
>> net.inet.sctp.asconf_auth_nochk: 0
>> net.inet.sctp.auth_disable: 0
>> net.inet.sctp.nat_friendly: 1
>> net.inet.sctp.abc_l_var: 2
>> net.inet.sctp.max_chained_mbufs: 5
>> net.inet.sctp.do_sctp_drain: 1
>> net.inet.sctp.hb_max_burst: 4
>> net.inet.sctp.abort_at_limit: 0
>> net.inet.sctp.strict_data_order: 0
>> net.inet.sctp.min_residual: 1452
>> net.inet.sctp.max_retran_chunk: 30
>> net.inet.sctp.log_level: 0
>> net.inet.sctp.default_cc_module: 0
>> net.inet.sctp.default_ss_module: 0
>> net.inet.sctp.default_frag_interleave: 1
>> net.inet.sctp.mobility_base: 0
>> net.inet.sctp.mobility_fasthandoff: 0
>> net.inet.sctp.udp_tunneling_port: 0
>> net.inet.sctp.enable_sack_immediately: 0
>> net.inet.sctp.nat_friendly_init: 0
>> net.inet.sctp.vtag_time_wait: 60
>> net.inet.sctp.buffer_splitting: 0
>> net.inet.sctp.initial_cwnd: 3
>> net.inet.sctp.rttvar_bw: 4
>> net.inet.sctp.rttvar_rtt: 5
>> net.inet.sctp.rttvar_eqret: 0
>> net.inet.sctp.rttvar_steady_step: 20
>> net.inet.sctp.use_dcccecn: 1
>> net.inet.sctp.blackhole: 0
>> net.inet.sctp.debug: 0
>>=20
>>=20
>> Regards,
>> Niu Zhixiong
>> =EF=BC=8D=EF=BC=8D=EF=BC=8D=EF=BC=8D=EF=BC=8D=EF=BC=8D=EF=BC=8D=EF=BC=8D=
=EF=BC=8D=EF=BC=8D=EF=BC=8D=EF=BC=8D=EF=BC=8D=EF=BC=8D=EF=BC=8D
>> kaiaixi@gmail.com
>> _______________________________________________
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>> To unsubscribe, send any mail to =
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>=20




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