Re: packet drop with intel gigabit / marwell gigabit

OxY wrote:

CPU utilization is 0% if apache is not running and 10-20%, when running and
serving 30-40 concurrent downloads (traffic is 3-4MB/s on fxp0 interface)

Is the number 3-4MB/s for per stream or the total for all 30-40 streams?
Are these downloads sent to a disk?

i measured the network performance with 'iperf' util, started the server on my box
and benchmarked with a client on the other gigabit machine.
it showed 0% packet drop, when apache was not running and 4-7%, when running..
then i checked how it behave when i shut down apache and init a local file copy from one
(not system!) disk to other (not system disk either). packet drop was 5-10%, due to the higher load.
so i think interrupts or just the load takes the network performance, but i have no clue how to fix it.
is it possible that the 2000+ xp amd is just weak to serve such a traffic? (em0 traffic's maximum is 18-23MB/s)
i think it might be around 30MB/s without packet drop.

First let's clear the notation -- Is 30MB/s (MBytes/s) = 240Mb/s (Mbit/s) or MB/s means Mbits/s
If MB/s is MBytes/s and you also write this amount data to a disk, plus other traffic on fxp0 to disk too,
then your problem may be bonded by memory bandwidth because CPU utilization is low:
(240 + 24~32) x 2 is about 535 Mbit/s (some chipset/motherboard has low memory BW for AMD)
If this is true, then this no thing you can tune. What does the chipset (Motherboard) this machine have?

I did FTP measurement, because what i want is to copy files with high speed from the
other gigabit machine. However FTP needs resources (CPU, I/O, etc), but iperf not!
iperf shows 20% CPU utilization when apache not running and when there's no packet drop.

ps: Now apache says: 14 requests currently being processed
traffic is 1MB/s on fxp0, and em0 benchmark with iperf says (64k udp window size):

[ 3] 0.0-10.0 sec 235 MBytes 197 Mbits/sec
[ 3] Sent 167375 datagrams
[ 3] Server Report:
[ 3] 0.0-10.0 sec 229 MBytes 192 Mbits/sec 0.066 ms 4115/167375 (2.5%)

the other gigabit machine is OK, because i have 0% packet drop, when my machine is totally idle.


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