System freezes with SMP support enabled

[Terry Lambert]

Aleksandr Melentiev wrote:
> Here's an exact behavior when SMP support is enabled:
> Hence, one network card is onboard which is an fxp0.
> 
> 5.0-RELEASE:
> Often spontaneous and constant 'watchdog timeouts' with different network
> cards that I have tried including SMC 1255 and 3Com 3C905-TX. An Intel
> Pro/100+ showed 'device timeout'. In all cases, system would stop
> responding. In most cases network connection would dissapear. Sometimes it
> would happen again on the first second after reboot. Onboard network card
> didnt show any errors! Only the PCI cards did.
> 
> 4.8-RELEASE:
> Same behavior as above, only no error messages whatsoever, network
> connection goes down and system locks up. It is not spontaneous, happens
> only when I try to transfer >1MB files locally via ftp (tried several
> different ftpd and clients too), maybe other ways of high-speed transfering
> are affected too. However, if I throttle my ftp client's upload speed to
> 15KBytes/sec, it transfers without a problem and systems stays stable.

I think we would still like to know:

1)	Is the "transfer >1MB files locally via ftp" necessary for
	the problem to exhibit on 5.0, as well?

2)	How long ago was your motherboard manufactured, and what
	chipset is it using?

	If it's a Mercury, Saturn, or Neptune chipset from Intel,
	you will definitely be limited to 2 PCI DMA masters at one
	time (chipset bug).

3)	Have you tried using the 8254 timer, instead of the PIIX
	timer?

I have other lower probability questions, but they can wait...	

-- Terry