Isn't Windows still running a BSD decendent IP stack?
Just thought I'd troll a little ;)
John
Sent from my BlackBerry device on the Rogers Wireless Network
-----Original Message----- From: "Adam Thompson" athompso@athompso.net Date: Sat, 17 Apr 2010 14:34:39 To: 'Continuation of Round Table discussion'roundtable@muug.mb.ca Subject: Re: [RndTbl] NIC performance with iperf
I installed a cheap GigE switch for a customer using 2006-era P4 Dell desktops, running XP with cheap Broadcom GigE NICs. Constant 600-700mbit for file transfers. CPU I think was ~30%, but that may have included the AV scanning the file.
I assumed Iperf is developed/optimized natively under *NIX and the Windows version is compiled under Cygwin, do you have any indication that it's optimized?
I'm certain iperf is NOT optimized for Windows. However, empirically I can determine using application-level tests (i.e. FTP, SAMBA, etc.) that the numbers I'm seeing are consistent.
Worth mentioning is that Microsoft shipped "ttcp.exe" on most versions of Windows XP install media, under VALUEADD\NET\something, IIRC. Presumably that binary is reasonably-well optimized. I recall using it to test between Windows XP and Solaris, and seeing half-decent speeds but nothing wonderful (~400Mbps).
Equally, I know that I too, have seen lesser Windows clients talking to Windows servers at higher speeds. It's also worth noting that SMB traffic to my Linux box is noticeably slower than it was to the Sun Ultra Enterprise 450 it replaced. While there's obviously something wrong with the networking stack on my Windows 7 PC (100% CPU utilization just to do TCP?!) it's also possible that there's some specific interaction between the Linux and Windows stacks.
As I demonstrated, Linux-to-linux works great. Kevin demonstrated that MacOSX-Linux works great. Many of us have anecdotal evidence that Windows-Windows works well, and several people have recently demonstrated that Windows-Linux does NOT work well. And I've personally demonstrated (although I haven't posted any numbers here) that Windows-Solaris (*not* OpenSolaris, if it makes any difference) works better than Windows-Linux.
(OK, I engaged in a bit of Windows-bashing when I blamed the Windows networking stack *exclusively*.)
I don't have any desire to set up a test lab in my living room just to try out the various combinations... how much effect can the GigE switch have on performance? I'm using dirt-cheap D-Link 5-port switches if that makes any difference.
-Adam Thompson athompso@athompso.net (204) 291-7950
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