Re: Linux 2.2.2 TCP delays every 41st small packet by 10-20 ms

Alan Cox (alan@lxorguk.ukuu.org.uk)
Thu, 25 Feb 1999 21:18:12 +0000 (GMT)


> collected timestamps from the Pentium II tick counter. This has the CPU
> clock frequency resolution (400 MHz in our case). Our systems use
> NetGear FA310TX cards (some with DEC chips, most with Lite-On chips) and
> the latest testing version 0.90Q of tulip.c driver.

Ok. When you do the run are you tcpdumping the receiver side to see if there
are lost frames ?

> Finally, I found it rather curious that a stalled MPI code would
> sometimes resume running if we sent a single "ping" to all hosts.

Thats quite interesting, although it may be simply that it kicked in timewise
while you were doing the ping. That can be hard to measure quantitively.

Alan

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