Jeremy M. Guthrie writes:
> Yeah, the load will be high. I'm expecting this to be watching ~ 750 mbps
> next December. The app profiles all traffic going in and out of our data
BW itself or pps is that not much of challange as handling of concurrent
> I'm not showing the /proc/net/rt_cache_stat file. Was there a kernel
> option I need to recompile with for rt_cache_stat to show up in proc?
No it's there without any options. Would be nice to the output from rtstat
> > Also check that the CPU shares the RX packet load. CPU0 affinty to eth0
> > and CPU1 to eth1 seems to be best. It gives cache bouncing at "TX" and
> > slab jobs but we have accept that for now.
> How would I go about doing this?
Assume you route packets between eth0 <-> eth1
Set eth0 irq to CPU0 and eth1 to CPU1 with /proc/irq/XX/smp_affinity
Disable irqbalancer etc.
> cat /proc/net/softnet_stat
total droppped tsquz Throttl FR_hit FR_succe FR_defer FR_def_o
> 5592c972 00000000 00001fc8 00000000 00000000 00000000 00000000 00000000
> 000f1991 00000000 00000000 00000000 00000000 00000000 00000000 00000000
See! One line per CPU. So CPU0 is handing almost all packets.
> Show the percentage of time spent by the CPU or CPUs to service
> softirqs. A softirq (software interrupt) is one of up to 32
> enumerated software interrupts which can run on multiple CPUs
Well yes. I had a more specific question. I'll look into mpstat where do
find it? Kernel pacthes?
Be also aware that packet forwarding with SMP/NUMA is very much research
today it is not that easy or not even possible to get aggregated performance
from several CPU's. in any setup. Well anyway we are beginning to see some
benefits now as we better understand the problems.