NetBSD hardclock overhead growth

[John Klos <john%ziaspace.com@localhost>]

Hi,

I was testing various versions of NetBSD on a VAXstation VLC to look at 
performance over time and attempting to characterize hardclock overhead. I 
have NetBSD 1.4, 1.5, 1.6, 6, 7 and current all NFS bootable. All were 
booted single user so no other daemons were running (just init and sh).

It seems that code generation hasn't changed enough to be a factor in 
small synthetic benchmarks such as benchmarks/dhrystone.

Each compile was timed:
time cc -O2  -DMSC_CLOCK    dhry_1.c dhry_2.c  -o dry2

dry2 binary sizes:
1.4:	13801
1.5:	13822
1.6:	10687
6:	11968

NetBSD 1.4 results:
       69.05 real        54.71 user        10.61 sys
Microseconds for one run through Dhrystone:  396.0
Dhrystones per Second:                      2525.3

NetBSD 1.5 results:
       75.36 real        57.13 user        10.58 sys
Microseconds for one run through Dhrystone:  427.0
Dhrystones per Second:                      2341.9

NetBSD 1.6 results:
       97.40 real        80.31 user        10.98 sys
Microseconds for one run through Dhrystone:  444.5
Dhrystones per Second:                      2249.7

NetBSD 6 results:
      278.23 real       229.45 user        33.60 sys
Microseconds for one run through Dhrystone:  472.2
Dhrystones per Second:                      2117.7
1.6 binary:
Microseconds for one run through Dhrystone:  465.6
Dhrystones per Second:                      2147.8


NetBSD 7 results (from NetBSD 6 binary since NetBSD 7 can't compile):
Microseconds for one run through Dhrystone:  489.8
Dhrystones per Second:                      2041.6

NetBSD 7 with 1.6 binary:
Microseconds for one run through Dhrystone:  489.7
Dhrystones per Second:                      2042.1

(NetBSD 7 panics when trying to run aout binaries)

This isn't enough data to calculate hardclock overhead. Results from 
another machine would be needed. I will have my (repaired) VAXstation 
4000/90a back soon and will test again with that machine.

Is anyone actively running NetBSD on an 11/780? :)

John