Messages in this thread | ![/](/images/icornerl.gif) | | Date | Thu, 28 Mar 1996 07:00:13 -0800 (PST) | From | Christoph Lameter <> | Subject | Re: PPP slowdown (Was Re: No Interrupt latency but too many interrupts) |
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> > I observed that my system still has a load of 0.30 when totally idle > > so I had a look at the interrupts and although the serial port > > was not in use there were still a couple of hundred interrupts > > per second. > > I think this may be a separate problem. My loadav is usually 0.01 to 0.03 > but I still get PPP slowdown. You are right. There was a FAX transmission that was desperately trying to complete but had timeouts because of the serial performance. I just checked for PPP or dialup events before I posted. Sorry. > > > How could the serial port generate so many interrupts while not in use? > > Where do you get this info ? /proc/interrupts doesn't seem to report this. It does. Just do a repeated cat /proc/interrupts and see how the values change. > > > Were there any modifications to the serial driver lately? > > In my searches through the kernel patches I mentioned, I have found only > two major changes within the serial/ppp code. These are the addition of > IPX (which I think is the likely culprit), and the addition of some > additional ioctls. All of this is part of the 1.3.72 patch which is about > when the complaints started (correct me if that's wrong). There is also a major reworking of the Interrupt code in arch/i386/irq.c which could be the culprit. Someone mentioned that the timer code also was changed.
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