<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40">
<head>
<meta http-equiv=Content-Type content="text/html; charset=utf-8">
<meta name=Generator content="Microsoft Word 12 (filtered medium)">
<style>
<!--
/* Font Definitions */
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:Tahoma;
panose-1:2 11 6 4 3 5 4 4 2 4;}
@font-face
{font-family:"Lucida Sans Typewriter";
panose-1:2 11 5 9 3 5 4 3 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman","serif";}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
span.EmailStyle17
{mso-style-type:personal-reply;
font-family:"Lucida Sans Typewriter";
color:#1F497D;}
.MsoChpDefault
{mso-style-type:export-only;}
@page Section1
{size:8.5in 11.0in;
margin:1.0in 1.0in 1.0in 1.0in;}
div.Section1
{page:Section1;}
-->
</style>
<!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]-->
</head>
<body lang=EN-CA link=blue vlink=purple>
<div class=Section1>
<p class=MsoNormal><span style='font-size:9.0pt;font-family:"Lucida Sans Typewriter";
color:#1F497D'>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.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:9.0pt;font-family:"Lucida Sans Typewriter";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:9.0pt;font-family:"Lucida Sans Typewriter";
color:#1F497D'>Can you tell us what kernel version, and what Windows version,
you’re running?<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:9.0pt;font-family:"Lucida Sans Typewriter";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:9.0pt;font-family:"Lucida Sans Typewriter";
color:#1F497D'>Also, do you happen to have a third system from which you could provide
comparative results?<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:9.0pt;font-family:"Lucida Sans Typewriter";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:9.0pt;font-family:"Lucida Sans Typewriter";
color:#1F497D'>-Adam Thompson <o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:9.0pt;font-family:"Lucida Sans Typewriter";
color:#1F497D'> <athompso@athompso.net><o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:9.0pt;font-family:"Lucida Sans Typewriter";
color:#1F497D'> (204) 291-7950<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:9.0pt;font-family:"Lucida Sans Typewriter";
color:#1F497D'><o:p> </o:p></span></p>
<div style='border:none;border-left:solid blue 1.5pt;padding:0in 0in 0in 4.0pt'>
<div>
<div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'>
<p class=MsoNormal><b><span lang=EN-US style='font-size:10.0pt;font-family:
"Tahoma","sans-serif"'>From:</span></b><span lang=EN-US style='font-size:10.0pt;
font-family:"Tahoma","sans-serif"'> roundtable-bounces@muug.mb.ca
[mailto:roundtable-bounces@muug.mb.ca] <b>On Behalf Of </b>Kevin McGregor<br>
<b>Sent:</b> Monday, April 05, 2010 19:27<br>
<b>To:</b> MUUG Roundtable<br>
<b>Subject:</b> [RndTbl] Network performance tuning<o:p></o:p></span></p>
</div>
</div>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>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<o:p></o:p></p>
<div>
<p class=MsoNormal> 0.0-60.0 sec 4.23 GBytes 606 Mbits/sec<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
<div>
<p class=MsoNormal>Reversed (iperf "server" running on Ubuntu server,
client running on the PC), I get<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal> 0.0-60.0 sec 1.13 GBytes 162 Mbits/sec<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
<div>
<p class=MsoNormal>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?<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
<div>
<p class=MsoNormal>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?<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
<div>
<p class=MsoNormal>Kevin<o:p></o:p></p>
</div>
</div>
</div>
</body>
</html>