Host-only interface works OK in Linux guests but extremely slow in Windows guest

[Ante Blaskovic]

I have Ubuntu 9.04 2.6.28-19-server as host and multiple guests with host-only networking with virtio drivers.

1 Windows XP guest 2 Ubuntu 10.04 guests

On host machine transfers between Linux guests are around 20 MB/s.

data2.cab                                                   100%  377MB  25.1MB/s   00:15

Problem is transfers from Windows guest to Linux guests, speeds are only about 4 MB/s using WinSCP. Transfers over LAN using IP tables routing have even bigger problem for Windows guest, speed is around 150-160KB/s while Linux guests have normal internet speeds of about 5MB/s.

[Ante Blaskovic]

Windows XP log

[Ante Blaskovic]

Ubuntu log

[Ante Blaskovic]

I've installed Apache web server on each guest and put there 200MB files + mini test from Speedtest.net

192.168..40 is Windows XP guest - download speed from Apache is about 150-160KB/s 192.168..50 is Linux guest - download speed from Apache is about 800-900KB/s

I have these iptables rules

-A POSTROUTING -s 192.168.0.40/32  -j SNAT --to-source x.x.x.
-A POSTROUTING -s 192.168.0.50/32  -j SNAT --to-source x.x.x.x
-A PREROUTING -d x.x.x.x/32 -j DNAT -p tcp -m tcp --dport 9090 --to-destination 192.168.0.40
-A PREROUTING -d x.x.x.x/32 -j DNAT -p tcp -m tcp --dport 8080 --to-destination 192.168.0.50

I've attached machine logs.

How come download speeds from Windows guest are few times slower than from Linux guests ?

[Frank Mehnert]

Did you test the updated patch from #7081 yet?

[Ante Blaskovic]

I tested it but didn't helped.

[Frank Mehnert]

Your Windows guest somehow switches to a high timer frequency (1000Hz). Did you install some special software? These TM: Giving up catch-up attempt at a 60 003 030 899 ns lag; new total are definitely problematic though it is not clear if they are related to your specific problem.

[Ante Blaskovic]

No special software. Only idle SQL servers but I now disables them. I was doing more tests. Speedtest.net test show always great difference between host and windows guest. Difference is more evident in upload speeds but download speeds are also affected. Tests to same server show around 50% -100% less bandwidth from guest than from the host.

[Ante Blaskovic]

I did more tests. Installed apache2 web server on windows and linux guests. Testing downloads from both server either using big file or speedtest mini test but this time using host. No iptables this time. download: windows - 40000kbps linux - 180000kbps

upload: windows - 90000kbps linux - 320000kbps

More or less 3-4 times slower on windows than on linux.

[Ante Blaskovic]

If someone wants to look closer at this issue I will provide him full access to servers and all needed help from me.

[Aleksey Ilyushin]

ante,

I see in the logs that you have configured both PCNet and E1000 adapters in XP guest. Which one is actually used in your tests? Notice that you use virtio-net in Linux guest. Can you use the same adapter (of your choice) in both XP and Linux guests and post the results?

[Ante Blaskovic]

Posted new log files (both machines have virtio-net), you can test download speed if you want,

xp - ​http://188.40.43.75:9090/ ubuntu - ​http://188.40.43.75:8080/

I put some test files, machines are on fast 100Mbit link, you will see that linux web server is really fast while xp is too slow.

From another server inside LAN I have this speeds, this is also about 2x times slower, I would expect maybe 10%-20% percent slower speeds from windows guest but not the 2x slower.

LAN test

-- xp

wget ​http://188.40.43.75:9090/test.rar

26,215,848 4.15M/s eta 40s -- ubuntu

wget ​http://188.40.43.75:8080/test.rar

62,459,608 10.7M/s eta 13s

[Ante Blaskovic]

I made another VM with Win7 32bit and it works OK. It looks now problem is only with XP guest.

[Aleksey Ilyushin]

I was able to get the same results locally: Linux guest to remote host is 846Mbit/s, while XP guest is 481Mbit/s. We are working on improving network performance, but there is no immediate solution. Thanks for the report! I'll keep you posted.

[aeichner]

Please reopen if still relevant with a recent VirtualBox release.