Hello,
This problem was also posted to netdev@xxxxxxxxxxx since I though it might
be good with some more eyes on the problem.
Short version: 82547GI with ITR=0 on 2.4.28 (vanilla) and RHEL3u3 has
problems (traffic grinds to a temporary halt under anything but trivila
network traffic). kernel prints the following and resets the IF (many
times):
NETDEV WATCHDOG: eth0: transmit timed out
More verbose version with background:
I have a problem with e1000 being unstable when I run it with
InterruptThrottleRate=0 (abbreviated ITR in the rest of this e-mail). I
need to turn ITR off or set it so large that it behaves as off. The reason
for having to turn it off is that I run MPI-applications (cluster stuff)
and that happens to be largely latency bound.
Latency with default e1000 is terrible, 250 us, with ITR=0 (where it
works) the latency drops to 20-25 us.
Enough of background. Up untill now I have allways been able to run with
ITR=0 and intel gigabit has been very nice. Now, for some combinations of
driver, chip and ITR setting it all falls apart.
Affected chips (theory, 8254X, X>1 or anything faster then PCI33):
82547GI, 82546 (said to be affected, not verified by me)
Unaffected chips:
82541 (rock solid no matter what driver or ITR)
Linux-2.4.26 vanilla (smp, without NAPI with e1000 as module) is ok
(82547, ITR=0, rock solid)
Linux-2.4.28 vanilla (smp, without NAPI with e1000 as module) is BAD
(82547 needs ITR<20000 for resonable stability)
Linux-2.4.28 with e1000 from 2.4.26 but otherwise exactly as above is ok
rock solid!!!
Linux-2.4.21-20smp RHEL3 update 3 is BAD
(known stable with default ITR (1?) but probably ok for <20000)
Conclusions: something happened above e1000 version 5.2.30 (as in
linux-2.4.26), RHEL has 5.2.52 and 2.4.28 has 5.4.11.
Some more discussions on this subject has taken place on another list, see
following thread if interested:
http://lists.us.dell.com/pipermail/linux-poweredge/2004-November/023061.html
Best Regards,
Peter
--
------------------------------------------------------------
Peter Kjellstroem | E-mail: cap@xxxxxxxxxx
National Supercomputer Centre |
Sweden | http://www.nsc.liu.se
-
: send the line "unsubscribe linux-net" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
