[RndTbl] Network performance tuning

Adam Thompson athompso at athompso.net
Mon Apr 5 21:16:50 CDT 2010

I don’t have much constructive to offer here, but I’ve heard several people encounter much the same thing – asymmetric network performance between a Windows PC and a Linux file server.  Your observations, however, by using iperf, exclude SAMBA – which means it’s not a SAMBA-specific problem, it’s a Linux-TCP-stack-to-Windows-TCP-stack problem.


Can you tell us what kernel version, and what Windows version, you’re running?


Also, do you happen to have a third system from which you could provide comparative results?


-Adam Thompson 

 <athompso at athompso.net>

 (204) 291-7950


From: roundtable-bounces at muug.mb.ca [mailto:roundtable-bounces at muug.mb.ca] On Behalf Of Kevin McGregor
Sent: Monday, April 05, 2010 19:27
To: MUUG Roundtable
Subject: [RndTbl] Network performance tuning


I've been trying to narrow down where my performance bottleneck(s) is (are). I just ran "iperf" from a Windows PC (XP SP3) to my Ubuntu 9.10 server. With iperf in "server" mode on the PC, and the client running on the Ubuntu machine, I get

 0.0-60.0 sec  4.23 GBytes   606 Mbits/sec


Reversed (iperf "server" running on Ubuntu server, client running on the PC), I get

 0.0-60.0 sec  1.13 GBytes   162 Mbits/sec


Wha...?? Both client and server runs on the PC report TCP window size to be 8 KB, but the Linux client reports 22.4 KB and the Linux server reports 85.3 KB. Increasing that to 256K on both ends has little effect. Does anyone have any suggestions?


The Windows NIC is a Realtek RTL8169/8110 Family Gigabit Ethernet; the Ubuntu server is using the Realtek Semiconductor Co., Ltd. RTL8111/8168B PCI Express Gigabit Ethernet controller (rev 01). Time to replace a NIC or two?



-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://www.muug.mb.ca/pipermail/roundtable/attachments/20100405/f7fb2aaf/attachment.html 

More information about the Roundtable mailing list