Messages in this thread | | | Subject | Re: TG3: very high CPU usage | From | Tom Sightler <> | Date | Tue, 20 Jan 2004 22:19:22 -0500 |
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On Tue, 2004-01-20 at 18:13, Lincoln Dale wrote: > At 11:33 PM 20/01/2004, JG wrote: > >i have also two boxes (one with 2.6.0, the other one 2.6.1-mm2) equipped > >with netgear ga302t cards (x-over cable). > >i don't see a very high cpu usage, but since upgrading to 2.6.x kernels i > >sometimes have really weird speed issues. i often only get transfer rates > >of about ~200-300 kilobytes/second...yes, and this over a gigabit > >interface, tested over ftp. > >i'm also running a nfs server on the 2.6.1-mm2 box, the 2.6.0 pc is the > >client, but again, sometimes it's *very* slow. if i reboot my 2.6.1-mm2 > >box (the other one is a server which can't be rebooted) it seems to be > >fine for some time. > > > >i didn't have such problems with 2.4.19 kernels on both pcs, there i got > >about 30-35MB/s over ftp without any problems, so i don't think it's > >hardware related.
I'm curious is the people seeing this problem happen to have preempt enabled in their config. I've noticed that my laptop, which also happens to have a tg3 based 10/100/1000 card, uses tons of CPU during trasfers, but only when preempt is enabled.
After looking into this, my Aironet wireless has exactly the same problem. When preempt is enabled a simple scp transfer running at approximately maximum speed for 802.11b (7.5Mb/sec) uses almost 70% of the CPU. The tg3 driver doing the same scp at 40Mb/sec (100Mb ethernet) uses > 90% of the CPU.
However, turning off preempt and my system runs at approximately the same speed on wireless (7.5Mb/sec) but only about 5% CPU. The tg3 driver with preempt disabled allows the scp to run at near wire speed (95-100Mb/sec) and uses only a fraction of the CPU.
Just curious if this might be what others are seeing.
Later, Tom
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