[Samba] Samba -> WinXP: slow transfers, partial solution
Marcello Romani
mromani at ottotecnica.com
Fri Jun 8 09:28:31 GMT 2007
Alexander Tsvyashchenko wrote:
>
>
> Hello All,
>
> I'm running Samba 3.0.24 as PDC and file server on Gentoo Linux,
> AMD64, 2.6.19 kernel, 100MBit/s network, and experience quite slow
> file transfers from Samba to WinXP SP2 clients: the speed is varying,
> but is about 1-2Mb/s at best.
>
> I spent quite some time investigating the issue, here are the
> intermediate results:
>
> 1) This happens only when transferring _from_ _Samba_ to _WinXP_.
>
> All other combinations are unaffected:
>
> a) Transferring from WinXP to Samba server is at 10Mb/s.
>
> b) Transfering to/from Samba server from Gentoo Linux on the same PC
> where WinXP is installed (so, completely the same hardware and
> connection) is also at normal speed.
>
> c) Transferring to/from WinXP to the server where Samba is installed
> using any other protocol (such as HTTPS or SCP) is also at normal speed.
>
> 2) CPU is at almost idle level both at client and server, so it's not
> the issue.
>
> 3) If there is any other network activity, transfer speed is increased
> up to normal level: f.e. doing two simulteneous transfers from Samba
> server to WinXP client gives 5Mb/s at each transfer, as expected.
>
> 4) Running tcpdump on server while the transfer is performed improves
> transfer speed in about 1.5 - 3 times, but still not to the normal
> speed.
>
> 5) Playing with "socket options" does not give any results.
>
> Specifically, using advices from the article
> http://www.dd.iij4u.or.jp/~okuyamak/Documents/tuning.english.html
> about SO_SNDBUF does not improve situation (but read below).
>
> 6) tcpdump + tcptrace show that there are a lot of retransmissions,
> see dumps below.
>
> 7) I've tested several WinXP clients with different hardware, all with
> the same results.
>
> 8) Samba logs looks normal to me, nothing special.
>
> Points (3) and (5), and also the article about SO_SNDBUF tuning gave
> me an idea that there might be smth wrong with ACKs sent from WinXP.
>
> I've tried to search for problems with ACK delays in WinXP and found
> the following articles:
>
> http://support.microsoft.com/kb/328890
> http://support.microsoft.com/kb/321098
>
> Based on them, I've done the following changes in WinXP registry:
>
> - set TcpAckFrequency to 1 to switch off delayed ACKs
> - set TcpDelAckTicks to 0 to disable delayed ACKs timer
>
> These changes did not help on their own. But combining them with the
> change of SO_SNDBUF to 1500 suddenly improved the speeds up to about 6
> Mb/s!
>
> It appeared that with these registry changes, setting SO_SNDBUF to any
> value in the range 1404 - 1872 gives the same speed of 6.0 - 6.4 Mb/s,
> while changing it even one byte lower / higher immmediately drops the
> speed to less than 1Mb/s.
>
> However, while this is partial solution I could live with, this is
> still not the normal speed, so I still would like to find the way to
> bring it to normal values.
>
> It seems that I'm not the only one who have similar problems: see BUGs
> 2117 and 3706 in Bugzilla, and discussion at Gentoo mailing list:
> http://forums.gentoo.org/viewtopic-p-2820556.html
>
> Please, let me know if any other information may be needed or if there
> are any other tests I can do to pin down the problem ...
>
> I'm attaching tcptrace logs for several sessions
> (all transfers are from Samba server to WinXP with registry changes
> applied,
> all transfers are done with the same file of the size 338Mb).
>
> 1) Samba -> WinXP without SO_SNDBUF set.
> (note that due to the "tcpdump effect" the speed is higher than in
> reality,
> also please note big number of retransmits)
>
> ================================
> TCP connection 3:
> host e: ***client***:1314
> host f: ***server***:445
> complete conn: no (SYNs: 0) (FINs: 0)
> first packet: Sat Apr 14 15:05:57.502839 2007
> last packet: Sat Apr 14 15:07:53.234397 2007
> elapsed time: 0:01:55.731558
> total packets: 425593
> filename: snd_buf_off.log
> e->f: f->e:
> total packets: 175858 total packets: 249735
> ack pkts sent: 175858 ack pkts sent: 249735
> pure acks sent: 164954 pure acks sent: 8
> sack pkts sent: 0 sack pkts sent: 0
> dsack pkts sent: 0 dsack pkts sent: 0
> max sack blks/ack: 0 max sack blks/ack: 0
> unique bytes sent: 690320 unique bytes sent: 356048963
> actual data pkts: 10904 actual data pkts: 249727
> actual data bytes: 690320 actual data bytes: 356319077
> rexmt data pkts: 0 rexmt data pkts: 195
> rexmt data bytes: 0 rexmt data bytes: 270114
> zwnd probe pkts: 0 zwnd probe pkts: 0
> zwnd probe bytes: 0 zwnd probe bytes: 0
> outoforder pkts: 0 outoforder pkts: 0
> pushed data pkts: 10904 pushed data pkts: 10982
> SYN/FIN pkts sent: 0/0 SYN/FIN pkts sent: 0/0
> urgent data pkts: 0 pkts urgent data pkts: 0
> pkts
> urgent data bytes: 0 bytes urgent data bytes: 0
> bytes
> mss requested: 0 bytes mss requested: 0
> bytes
> max segm size: 170 bytes max segm size: 1460
> bytes
> min segm size: 40 bytes min segm size: 39
> bytes
> avg segm size: 63 bytes avg segm size: 1426
> bytes
> max win adv: 65535 bytes max win adv: 24656
> bytes
> min win adv: 64099 bytes min win adv: 15008
> bytes
> zero win adv: 0 times zero win adv: 0
> times
> avg win adv: 65464 bytes avg win adv: 24655
> bytes
> max owin: 171 bytes max owin: 61504
> bytes
> min non-zero owin: 1 bytes min non-zero owin: 1
> bytes
> avg owin: 4 bytes avg owin: 28273
> bytes
> wavg owin: 0 bytes wavg owin: 16041
> bytes
> initial window: 138 bytes initial window: 0
> bytes
> initial window: 1 pkts initial window: 0
> pkts
> ttl stream length: NA ttl stream length: NA
> missed data: NA missed data: NA
> truncated data: 537664 bytes truncated data: 352822899
> bytes
> truncated packets: 10904 pkts truncated packets: 249727
> pkts
> data xmit time: 115.730 secs data xmit time: 115.730
> secs
> idletime max: 661.6 ms idletime max: 661.9
> ms
> throughput: 5965 Bps throughput: 3076507
> Bps
> ================================
>
> 2) Samba -> WinXP without SO_SNDBUF set, two simultaneous transfers
> (note there are no retransmits at all)
>
> ================================
> TCP connection 1:
> host a: ***client***:1314
> host b: ***server***:445
> complete conn: no (SYNs: 0) (FINs: 0)
> first packet: Sat Apr 14 15:35:27.213438 2007
> last packet: Sat Apr 14 15:36:31.474766 2007
> elapsed time: 0:01:04.261328
> total packets: 800651
> filename: simult_snd_buf_off.log
> a->b: b->a:
> total packets: 326843 total packets: 473808
> ack pkts sent: 326843 ack pkts sent: 473808
> pure acks sent: 306750 pure acks sent: 31
> sack pkts sent: 0 sack pkts sent: 2
> dsack pkts sent: 0 dsack pkts sent: 1
> max sack blks/ack: 0 max sack blks/ack: 1
> unique bytes sent: 1266917 unique bytes sent: 658967341
> actual data pkts: 20093 actual data pkts: 473777
> actual data bytes: 1266980 actual data bytes: 658967341
> rexmt data pkts: 1 rexmt data pkts: 0
> rexmt data bytes: 63 rexmt data bytes: 0
> zwnd probe pkts: 0 zwnd probe pkts: 0
> zwnd probe bytes: 0 zwnd probe bytes: 0
> outoforder pkts: 0 outoforder pkts: 0
> pushed data pkts: 20093 pushed data pkts: 25922
> SYN/FIN pkts sent: 0/0 SYN/FIN pkts sent: 0/0
> urgent data pkts: 0 pkts urgent data pkts: 0
> pkts
> urgent data bytes: 0 bytes urgent data bytes: 0
> bytes
> mss requested: 0 bytes mss requested: 0
> bytes
> max segm size: 148 bytes max segm size: 1460
> bytes
> min segm size: 40 bytes min segm size: 39
> bytes
> avg segm size: 63 bytes avg segm size: 1390
> bytes
> max win adv: 65535 bytes max win adv: 24656
> bytes
> min win adv: 51724 bytes min win adv: 24656
> bytes
> zero win adv: 0 times zero win adv: 0
> times
> avg win adv: 65472 bytes avg win adv: 24656
> bytes
> max owin: 18446744073709551554 bytes max owin:
> 69822 bytes
> min non-zero owin: 1 bytes min non-zero owin: 1
> bytes
> avg owin: 7 bytes avg owin: 45958
> bytes
> wavg owin: 7750572630405 bytes wavg owin:
> 50450 bytes
> initial window: 63 bytes initial window: 0
> bytes
> initial window: 1 pkts initial window: 0
> pkts
> ttl stream length: NA ttl stream length: NA
> missed data: NA missed data: NA
> truncated data: 985678 bytes truncated data: 652334463
> bytes
> truncated packets: 20093 pkts truncated packets: 473777
> pkts
> data xmit time: 64.257 secs data xmit time: 64.257
> secs
> idletime max: 2790.4 ms idletime max: 2790.6
> ms
> throughput: 19715 Bps throughput: 10254493
> Bps
> ================================
>
> 3) Samba -> WinXP with SO_SNDBUF set to 1500.
>
> ================================
> TCP connection 3:
> host e: ***client***:3878
> host f: ***server***:445
> complete conn: no (SYNs: 0) (FINs: 0)
> first packet: Sat Apr 14 18:18:59.800152 2007
> last packet: Sat Apr 14 18:20:05.035874 2007
> elapsed time: 0:01:05.235721
> total packets: 501414
> filename: snd_buf_on.log
> e->f: f->e:
> total packets: 251898 total packets: 249516
> ack pkts sent: 251898 ack pkts sent: 249516
> pure acks sent: 240994 pure acks sent: 10
> sack pkts sent: 0 sack pkts sent: 0
> dsack pkts sent: 0 dsack pkts sent: 0
> max sack blks/ack: 0 max sack blks/ack: 0
> unique bytes sent: 690320 unique bytes sent: 356048963
> actual data pkts: 10904 actual data pkts: 249506
> actual data bytes: 690320 actual data bytes: 356052623
> rexmt data pkts: 0 rexmt data pkts: 20
> rexmt data bytes: 0 rexmt data bytes: 3660
> zwnd probe pkts: 0 zwnd probe pkts: 0
> zwnd probe bytes: 0 zwnd probe bytes: 0
> outoforder pkts: 0 outoforder pkts: 0
> pushed data pkts: 10904 pushed data pkts: 10923
> SYN/FIN pkts sent: 0/0 SYN/FIN pkts sent: 0/0
> urgent data pkts: 0 pkts urgent data pkts: 0
> pkts
> urgent data bytes: 0 bytes urgent data bytes: 0
> bytes
> mss requested: 0 bytes mss requested: 0
> bytes
> max segm size: 170 bytes max segm size: 1460
> bytes
> min segm size: 40 bytes min segm size: 39
> bytes
> avg segm size: 63 bytes avg segm size: 1427
> bytes
> max win adv: 65535 bytes max win adv: 24656
> bytes
> min win adv: 64081 bytes min win adv: 24656
> bytes
> zero win adv: 0 times zero win adv: 0
> times
> avg win adv: 65483 bytes avg win adv: 24656
> bytes
> max owin: 171 bytes max owin: 2921
> bytes
> min non-zero owin: 1 bytes min non-zero owin: 1
> bytes
> avg owin: 3 bytes avg owin: 2805
> bytes
> wavg owin: 0 bytes wavg owin: 765
> bytes
> initial window: 138 bytes initial window: 0
> bytes
> initial window: 1 pkts initial window: 0
> pkts
> ttl stream length: NA ttl stream length: NA
> missed data: NA missed data: NA
> truncated data: 537664 bytes truncated data: 352559539
> bytes
> truncated packets: 10904 pkts truncated packets: 249506
> pkts
> data xmit time: 65.235 secs data xmit time: 65.235
> secs
> idletime max: 2000.5 ms idletime max: 2000.8
> ms
> throughput: 10582 Bps throughput: 5457883
> Bps
> ================================
>
> 4) Transfer from Samba server to WinXP using SCP protocol.
>
> ================================
> TCP connection 4:
> host g: ***client***:1501
> host h: ***server***:22
> complete conn: no (SYNs: 0) (FINs: 2)
> first packet: Sat Apr 14 15:25:26.305071 2007
> last packet: Sat Apr 14 15:25:57.316420 2007
> elapsed time: 0:00:31.011348
> total packets: 436782
> filename: scp.log
> g->h: h->g:
> total packets: 179196 total packets: 257586
> ack pkts sent: 179196 ack pkts sent: 257586
> pure acks sent: 174818 pure acks sent: 13
> sack pkts sent: 0 sack pkts sent: 0
> dsack pkts sent: 0 dsack pkts sent: 0
> max sack blks/ack: 0 max sack blks/ack: 0
> unique bytes sent: 210208 unique bytes sent: 356544464
> actual data pkts: 4377 actual data pkts: 257572
> actual data bytes: 210208 actual data bytes: 356544464
> rexmt data pkts: 0 rexmt data pkts: 0
> rexmt data bytes: 0 rexmt data bytes: 0
> zwnd probe pkts: 0 zwnd probe pkts: 0
> zwnd probe bytes: 0 zwnd probe bytes: 0
> outoforder pkts: 0 outoforder pkts: 0
> pushed data pkts: 4377 pushed data pkts: 21912
> SYN/FIN pkts sent: 0/1 SYN/FIN pkts sent: 0/1
> urgent data pkts: 0 pkts urgent data pkts: 0
> pkts
> urgent data bytes: 0 bytes urgent data bytes: 0
> bytes
> mss requested: 0 bytes mss requested: 0
> bytes
> max segm size: 96 bytes max segm size: 1460
> bytes
> min segm size: 32 bytes min segm size: 28
> bytes
> avg segm size: 48 bytes avg segm size: 1384
> bytes
> max win adv: 65535 bytes max win adv: 8272
> bytes
> min win adv: 22451 bytes min win adv: 8272
> bytes
> zero win adv: 0 times zero win adv: 0
> times
> avg win adv: 62839 bytes avg win adv: 8272
> bytes
> max owin: 97 bytes max owin: 65501
> bytes
> min non-zero owin: 1 bytes min non-zero owin: 1
> bytes
> avg owin: 5 bytes avg owin: 50602
> bytes
> wavg owin: 0 bytes wavg owin: 56657
> bytes
> initial window: 80 bytes initial window: 0
> bytes
> initial window: 1 pkts initial window: 0
> pkts
> ttl stream length: NA ttl stream length: NA
> missed data: NA missed data: NA
> truncated data: 148930 bytes truncated data: 352938456
> bytes
> truncated packets: 4377 pkts truncated packets: 257572
> pkts
> data xmit time: 31.010 secs data xmit time: 31.004
> secs
> idletime max: 101.0 ms idletime max: 103.8
> ms
> throughput: 6778 Bps throughput: 11497225
> Bps
> ================================
>
> Thanks!
>
> Good luck! Alexander
>
>
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>
I would like to report that the suggestion listed in this e-mail improved my
transfer speed dramtcally.
Thanks alexander.
My environment is as follows:
Server:
Pentium IV 2.60 GHz Hyperthreading enabled, 2GB RAM, software raid1 on two
37GB 10krpm U160 scsi disks.
Network: GB ethernet on the server
uname -a:
Linux serverlinux 2.6.16-gentoo-r9 #3 SMP Fri Mar 23 12:55:22 CET 2007 i686
Intel(R) Pentium(R) 4 CPU 2.60GHz GenuineIntel GNU/Linux
smbd --version:
Version 3.0.22
Client: Windows XP SP2, up-to-date with the latest windows update fixes.
Athlon XP 2GHz, 1GB ram, 40GB IDE drive.
Network: 100MBit ethernet.
The problem:
I was working on a 17MB OpenOffice Writer document, which is stored on our
main network share. The time required to load the document was quite high,
but acceptable. Saving the document, though, took almost 30 to 40 seconds.
During the saving process, both the server and client CPUs were almost idle,
the network usage measured on the client was around 2% and the r/w load on
the server disks were very low.
The average transfer rate reported by tcptrace was around 150Kb/s
I applied the registry modifications on the client and rebotted the machine:
the situation was the same.
Then I applied the SO_SNDBUF modification on the server and did a killall
-HUP smbd. Now the transfer rate reported by tcptrace has bumped up to a
respectable 1Mb/s, and the load/save times experienced while working on the
document are back to normality.
The tcptrace report _before_ applying the modifications is:
(.201 is the server, .19 is the client)
TCP connection 2:
host c: 192.9.200.19:1133
host d: 192.9.200.201:445
complete conn: no (SYNs: 0) (FINs: 0)
first packet: Fri Jun 8 10:32:18.486390 2007
last packet: Fri Jun 8 10:34:15.324113 2007
elapsed time: 0:01:56.837723
total packets: 44000
filename: ced.dump
c->d: d->c:
total packets: 17796 total packets: 26204
ack pkts sent: 17796 ack pkts sent: 26204
pure acks sent: 4003 pure acks sent: 6480
sack pkts sent: 5 sack pkts sent: 423
dsack pkts sent: 0 dsack pkts sent: 60
max sack blks/ack: 1 max sack blks/ack: 1
unique bytes sent: 17630024 unique bytes sent: 25753790
actual data pkts: 13793 actual data pkts: 19724
actual data bytes: 17717624 actual data bytes: 26294993
rexmt data pkts: 60 rexmt data pkts: 429
rexmt data bytes: 87600 rexmt data bytes: 541203
zwnd probe pkts: 0 zwnd probe pkts: 0
zwnd probe bytes: 0 zwnd probe bytes: 0
outoforder pkts: 258 outoforder pkts: 0
pushed data pkts: 2004 pushed data pkts: 2368
SYN/FIN pkts sent: 0/0 SYN/FIN pkts sent: 0/0
urgent data pkts: 0 pkts urgent data pkts: 0
pkts
urgent data bytes: 0 bytes urgent data bytes: 0
bytes
mss requested: 0 bytes mss requested: 0
bytes
max segm size: 1460 bytes max segm size: 1460
bytes
min segm size: 41 bytes min segm size: 39
bytes
avg segm size: 1284 bytes avg segm size: 1333
bytes
max win adv: 65535 bytes max win adv: 32767
bytes
min win adv: 64079 bytes min win adv: 32767
bytes
zero win adv: 0 times zero win adv: 0
times
avg win adv: 64998 bytes avg win adv: 32767
bytes
initial window: 198 bytes initial window: 0
bytes
initial window: 1 pkts initial window: 0
pkts
ttl stream length: NA ttl stream length: NA
missed data: NA missed data: NA
truncated data: 17524522 bytes truncated data: 26018857
bytes
truncated packets: 13793 pkts truncated packets: 19724
pkts
data xmit time: 116.836 secs data xmit time: 116.837
secs
idletime max: 10705.3 ms idletime max: 10706.0 ms
throughput: 150893 Bps throughput: 220424 Bps
The report _afeter_ the modification is instead:
TCP connection 2:
host c: 192.9.200.19:1076
host d: 192.9.200.201:445
complete conn: no (SYNs: 0) (FINs: 0)
first packet: Fri Jun 8 11:06:50.522285 2007
last packet: Fri Jun 8 11:07:07.647955 2007
elapsed time: 0:00:17.125670
total packets: 55619
filename:
ced.dump.TcpAckFrequency1.TcpDelAckTicks0.sosndbuf1500
c->d: d->c:
total packets: 29699 total packets: 25920
ack pkts sent: 29699 ack pkts sent: 25920
pure acks sent: 15872 pure acks sent: 6387
sack pkts sent: 0 sack pkts sent: 379
dsack pkts sent: 0 dsack pkts sent: 59
max sack blks/ack: 0 max sack blks/ack: 1
unique bytes sent: 17632261 unique bytes sent: 26066694
actual data pkts: 13827 actual data pkts: 19533
actual data bytes: 17718401 actual data bytes: 26066694
rexmt data pkts: 59 rexmt data pkts: 0
rexmt data bytes: 86140 rexmt data bytes: 0
zwnd probe pkts: 0 zwnd probe pkts: 0
zwnd probe bytes: 0 zwnd probe bytes: 0
outoforder pkts: 214 outoforder pkts: 0
pushed data pkts: 2039 pushed data pkts: 2324
SYN/FIN pkts sent: 0/0 SYN/FIN pkts sent: 0/0
urgent data pkts: 0 pkts urgent data pkts: 0
pkts
urgent data bytes: 0 bytes urgent data bytes: 0
bytes
mss requested: 0 bytes mss requested: 0
bytes
max segm size: 1460 bytes max segm size: 1460
bytes
min segm size: 41 bytes min segm size: 39
bytes
avg segm size: 1281 bytes avg segm size: 1334
bytes
max win adv: 65535 bytes max win adv: 32767
bytes
min win adv: 64076 bytes min win adv: 32767
bytes
zero win adv: 0 times zero win adv: 0
times
avg win adv: 65157 bytes avg win adv: 32767
bytes
initial window: 198 bytes initial window: 0
bytes
initial window: 1 pkts initial window: 0
pkts
ttl stream length: NA ttl stream length: NA
missed data: NA missed data: NA
truncated data: 17524823 bytes truncated data: 25793232
bytes
truncated packets: 13827 pkts truncated packets: 19533
pkts
data xmit time: 17.124 secs data xmit time: 17.125
secs
idletime max: 7717.0 ms idletime max: 7717.2 ms
throughput: 1029581 Bps throughput: 1522083 Bps
Please note the following details:
Before:
idletime max: 10705.3 ms idletime max: 10706.0 ms
throughput: 150893 Bps throughput: 220424 Bps
After:
idletime max: 7717.0 ms idletime max: 7717.2 ms
throughput: 1029581 Bps throughput: 1522083 Bps
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