Re: [9fans] interesting timing tests

[erik quanstrom <quanstro@quanstro.net>]

On Sat Jun 19 09:44:25 EDT 2010, 9fans@hamnavoe.com wrote:
> > note the extreme system time on the 16 processor machine
>
> kprof(3)

i'm not sure i completely trust kprof these days.  there
seems to be a lot of sampling error.  the last time i tried to
use it to get timing on esp, encryption didn't show up at all
in kprof's output.  trace(3) showed that encryption was 80%
of the total cpu use.  in any event, i was suspecting that ilock
would be a big loser as nproc goes up, and it does appear to
be.  i'm less sure that runproc is really using 62% of the cpu

c; kprof /386/9pccpu /dev/kpdata
total: 70023	in kernel text: 65773	outside kernel text: 4250
KTZERO f0100000
ms	  %	sym
40984	 62.3	runproc
9930	 15.0	ilock
5720	  8.6	_cycles
4360	  6.6	perfticks
1784	  2.7	isaconfig
1600	  2.4	iunlock

cf. the 4 processor 5600 xeon:

b; kprof /386/9pccpu /dev/kpdata
total: 14416	in kernel text: 11434	outside kernel text: 2982
KTZERO f0100000
ms	  %	sym
4036	 35.2	rebalance
2483	 21.7	runproc
1561	 13.6	_cycles
918	  8.0	perfticks
377	  3.2	unlock
337	  2.9	microdelay
259	  2.2	idlehands

- erik