Re: Fedora SMP dual core, dual AMD 64 processor system
"Bryan J. Smith" <[email protected]>
| Newsgroups | gmane.linux.redhat.amd64 |
|---|---|
| Message-ID | <[email protected]> |
On Sat, 2005-09-24 at 16:38 -0400, Mark Hahn wrote: > sure, but so what? so SW raid will need to transfer a few extra > chunks over some of the 8GB/s HT channels, among some of the > 26 GB/s of memory bandwidth available. I didn't know Opterons could distribute the I/O operations across CPUs to use all that memory bandwidth. You're throwing around theoretical and aggregate maximums like that's actually what you're going to get. > why do you think that a few hundred MB/s out of many GB/s is going > to make a difference? Yes, when you're moving those MBs through the CPU and turning it all into one huge Programmed I/O (PIO) operation. You're not going to get GBps in transfers. You're losing valuable chunks of time and, therefore, cutting cycles away from transfer time as well. Again, if it takes up 50% of your cycles just to push hundreds of MBs data through the CPU, then you have reduced all that theoretical bandwidth significantly. > how strange! what on earth do you think you can do with disks > at 4 GB/s? or are you worried about streaming reads from ~50 > disks at once? But you're not getting 4GBps. At this point, I need to bow out of this discussion. It's obvious that you believe you can push 8GB of data through your CPU in a second. -- Bryan J. Smith [email protected] http://thebs413.blogspot.com ---------------------------------------------------------------------- The best things in life are NOT free - which is why life is easiest if you save all the bills until you can share them with the perfect woman