tuning for high connection rates

[Philipp Wuensche]

Robert Watson wrote:
> 
> Could you show us the output from "top -S" left running for a few
> minutes in the steady state.
> 
> Could you try setting the sysctl net.isr.direct to 0, and see how that
> affects performance, CPU time reports, and "top -S" output?

I first had too look up what net.isr.direct does and I found
http://lists.freebsd.org/pipermail/freebsd-performance/2005-October/001561.html

Interesting, seems like the CPU usage switches between system and
interrupt, "swi1: net" pops up with 65% CPU. Interrupts go up to 2k
interrupts/sec. But in general the system usage stays the same, as far
as we can tell in this short time.

We will keep the system running with net.isr.direct=0 for a day or so to
get a better picture how the system performs over the day.

With net.isr.direct=1

CPU states:  1.9% user,  0.0% nice, 43.3% system,  9.8% interrupt, 45.0%
idle
Mem: 163M Active, 139M Inact, 695M Wired, 44K Cache, 213M Buf, 975M Free
Swap: 2048M Total, 2048M Free

  PID USERNAME     THR PRI NICE   SIZE    RES STATE  C   TIME   WCPU COMMAND
   23 root           1 -68    -     0K    16K CPU0   0  25.4H 66.46% em0
taskq
   11 root           1 171 ki31     0K    16K RUN    1  25.5H 47.22%
idle: cpu1
   12 root           1 171 ki31     0K    16K RUN    0  17.3H 38.92%
idle: cpu0
 7467 nobody         3  96    0   152M   146M ucond  1 153:18 24.61%
opentracke
   13 root           1 -32    -     0K    16K RUN    0 785:03 17.33%
swi4: cloc

With net.isr.direct=0

CPU states:  1.9% user,  0.0% nice, 11.1% system, 42.1% interrupt, 44.9%
idle
Mem: 151M Active, 139M Inact, 695M Wired, 44K Cache, 213M Buf, 987M Free
Swap: 2048M Total, 2048M Free

  PID USERNAME     THR PRI NICE   SIZE    RES STATE  C   TIME   WCPU COMMAND
   15 root           1 -44    -     0K    16K CPU0   0   2:49 64.70%
swi1: net
   11 root           1 171 ki31     0K    16K RUN    1  25.5H 46.09%
idle: cpu1
   12 root           1 171 ki31     0K    16K RUN    0  17.3H 36.18%
idle: cpu0
 7467 nobody         3  96    0   137M   132M ucond  1 154:28 26.37%
opentracke
   13 root           1 -32    -     0K    16K WAIT   1 786:38 17.48%
swi4: cloc
   23 root           1 -68    -     0K    16K -      0  25.4H  2.98% em0
taskq

greetings,
cryx