6.2 becomes unresponsive under high traffic

[Mikhail Teterin]

Hello!

The system is a dual Opteron 244 running today's FreeBSD-6.2/amd64.

em-interface connects it to the switch (in gigabit mode).

When I direct 2 database dumps at the machine in parallel (the arriving data 
is getting compressed and written to local disk), the "system" component of 
the load (as reported by systat and top) goes up to 99-100% and stays there 
for many minutes at a time. Accessing the box via console remains speedy, but 
remote connections stall for minutes during which the box is not even 
pingable...

What appears to wake it up, though, is hitting a (local) keyboard button...

Switching em0 to polling mode did not help...

"netstat -m" does not show any rejections of buffer requests.

It uses the BSD4-scheduler, as is the default.

Earlier, in the single-CPU configuration, the box had no problems dealing with 
such 2 data streams for hours, backing up all our databases. We added another 
processor and updated the world/kernel from 6.1 to 6.2, hoping to halve the 
dump times -- and it is barely crowling now...

Please, advise. Thanks!

	-mi