Messages in this thread | | | Date | Sun, 19 Apr 1998 19:04:00 +0200 (CEST) | From | MOLNAR Ingo <> | Subject | Re: NE2000 slow interrupts safe? |
| |
On Sun, 19 Apr 1998, Richard B. Johnson wrote:
> > Sigh. I don't think this is a significant factor, however, I've just > > run another series of tests where I disable interrupts in > > ne_block_input() and I get times ranging from 0.5 to 1 millisecond > > (for largish packets). This is with my PCI NE2000 card on a dual PPro. > > I mentioned before that your 'printer' port can be a valuable tool.
ktrace can be used too, you can 'record' system traces and analyze them later, accuracy of timestamps is 0.1 usecs or better. Eg:
36984 c010b467 do_IRQ +<13/108> (3.73) 36985 c5867177 _end +<555b35f/3fcf41e7> (4.93) 36986 c01b9221 add_mouse_randomness +<d/28> (0.49) 36987 c01b904b add_timer_randomness +<13/1b4> (2.83) 36988 c011147b wake_up_interruptible +<13/a0> (1.10) 36989 c011147b wake_up_interruptible +<13/a0> (2.61) 36990 c010b539 do_IRQ +<e5/108> (0.06) 36991 c010b551 do_IRQ +<fd/108> (0.63) 36992 c01111c7 schedule +<13/218> (5.83) ^- timestamp ^- function entry ^-- latency in usecs
shows that the timer IRQ had a latency of ~16 usecs until it got the the schedule() call. I'm sure those 2-4 msecs interrupts can be debugged with ktrace as well. One can even turn tracing on/off for certain interrupts, etc.
Keith Owens has posted the 'memleak+ktrace+xkdebug' debugging-patchset today, which includes a 2.1.97 (and improved) version of my ktracer as well, you can find the package at:
ftp://ftp.ocs.com.au/pub/patch-ikd-2.1.97.gz
it has extensive documentation, a FAQ and stuff.
-- mingo
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu
| |