On Thu, 7 Feb 2008, Devrim SERAL wrote:
So i realize that its related to Bus problem.. But i don't understand
why it's degraded to much! As i know 32bit/33Mhz give me at least 1
Gb/sec.
Is there somebody that explain this situation?
When I connect a RAID controller to 32bit/33MHz I usually only get 50-60
megabyte/s. Theoretical max is 133 megabyte/s. PCI is not 100% efficient.
In your case, if you only have single bus then packet needs to go
NIC->memory->NIC in the routing machine meaning it'll go over the PCI bus
twice, thus halving the bw.
With PCs, we also have the problem with interrupts/context switching being
fairly expensive performancewise, meaning the driver (if it uses NAPI or
not) can influense the performance quite a lot as well. This is the per
packet-problem people are "solving" by increasing the MTU.
I have managed to run 5-7 gigabit/s between two directly connected linux
machines with 8x PCI-E 10GE NICs (myricom) without changing any settings
at all basically. So it all comes down to hardware, you want fast buses to
run the packets on, and you need drivers that interact efficiently with
the NICs at high pps load.
--
Mikael Abrahamsson email: swmike@xxxxxxxxx
-
To unsubscribe from this list: send the line "unsubscribe linux-net" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
