CPU usage during solid throuput

[zephxiii]

Our connection is 7mbit down/2mbit up. I've noticed when we are downloading large files that max out the connect the cpu usage is pretty high at around 70-80%. From what I can tell the usage is falling under the "interrupt" category in RRD Graphs.

The machine has a PIII 1.13ghz cpu, and the only extra service i'm really running is the traffic shaper.

Is this normal or might it be something to do with the NIC offloading some work onto the CPU?

[Nachtfalke]

what type of NIC do you use ?
realtek ? If yes, it would help to use one good NIC like an intel.

[zephxiii]

It is a 3com NIC, and I do suspect it as the cause…but was trying to clue in on past experiences.

[Nachtfalke]

Did you play a little bit with the options under:
System: Advanced: Networking ?

I use the default values on an intel nic but perhaps some changes will help in your case if you could not try another nic right now.

[jimp]

from ssh or the console, watch "top -SH" as you experience the high load. See where the CPU is really going.

[zephxiii]

@jimp:

from ssh or the console, watch "top -SH" as you experience the high load. See where the CPU is really going.

Here's what I got:

[jimp]

Are you sure that was "top -SH"? It should have shown you the kernel threads using that cpu.

Next you could try:

systat -vmstat

See what is firing off those interrupts.

[zephxiii]

@jimp:

Are you sure that was "top -SH"? It should have shown you the kernel threads using that cpu.

Next you could try:

systat -vmstat

See what is firing off those interrupts.

Think the last post was just top