Greg Lindahl <[EMAIL PROTECTED]> writes: >> By the way, if you really can't afford for things to "go away" for >> 1/250th of a second very often, I have horrible news for you: NO >> COMPUTER WILL WORK FOR YOU. > > You haven't done much HPC, have you? Why do you think we build > interconnects with latencies on order 1 microsecond?
Insult me all you like. If you have any stock Intel architecture based machine, the machine will vanish into System Management Mode for long periods. SMM operates below the level of the operating system. The SM interrupt, which the OS cannot control, comes in, the processor goes into the protected SM BIOS with its own protected memory and stays there as long as it likes to do its job and returns. The OS is totally out of the loop on this. If you aren't aware of that, well, fine, but it is true. You can call me ignorant all day and it will still be true. I've had to build systems that synchronize their clocks to very very high precisions and it is a big issue in that situation. You can easily watch the effect on a machine where you're doing high precision timings. It is very, very difficult to do hard realtime on PCs because of this. So, if you claim that postfix will somehow do something unacceptable to your latencies and cause our mesh to desynchronize but you dont know about SM Mode, well, fine, but Postfix won't prevent your machine from processing interrupts, or prevent your OS from properly switching to a high priority process following an interrupt, but SMM will and you can't get rid of it. Perry -- Perry E. Metzger [EMAIL PROTECTED] _______________________________________________ Beowulf mailing list, Beowulf@beowulf.org To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf
