On 2010-04-14 Kevin McGregor wrote:
And finally (I'm kinda done messing around with this): I took out all other cards save for the AGP video card and re-ran iperf, and got 162 Mb/s with the XP PC sending to the Linux server and 612 Mb/s sending from the server to the PC. Unpleasantly asymmetric.
Finally had a mo to test my systems, which have similar problems.
my comps: pog : Fedora 12, Core2Q, PRO/1000 MT Server NIC piles : Fedora 10, PD 3G , PRO/1000 MT Server NIC peecee: XP, Core i7, PRO/1000 PT Desktop NIC (PCIe) switch: Linksys WebSmart SRW2016, jumbo OFF
All NICs have as much offloading turned on as possible.
iperf results in order of slow to fast:
-s -t piles peecee 300 pog peecee 351 peecee pog 400 peecee piles 401 piles pog 743 pog piles 744
Now, I can't seem to figure out whether it's the -s that's sending or the -t, so I just list as above. Very consistent results with anything involving the PC (my fastest hardware!) being much slower than I get linux->linux. Sure, the peecee has a "lesser" NIC, but it's still an expensive one.
The above results mirror what I see in daily life going from piles (file server) to peecee using samba (the only thing I care about from peecee).
When I have another mo, I'll boot a live linux CD and test peecee with that to see if it's the hw to blame or simply XP. I've seen lots of reports about XP having braindead TCP and regedit tweaks to make it faster. I've tried many of them with little success.
If anyone wants to also guess as to why my network speed about doubles when I turn OFF jumbo packets(!!!), please be my guest! (Yes, I'm pretty sure I had jumbos configured properly on all NICs/switch, etc.)
I'll wait a bit to see if any new AMD CPUs are coming out, and then buy a quad- or hex-core CPU/motherboard/RAM and hope for a decent network interface.
Or buy a nice NIC now :-) The onboard NICs are usually always substandard and often crippled (no jumbo, etc).