On 05/25/2014 06:06 PM, Charles Dickman wrote:
After listen to Holm's travails trying to get NetBSD running on his
vax stations I did a little experimenting.
test vax: VAXstation 4000 Model 60 with 104MB RAM
boot server: Pentium Celeron PC running NetBSD 6.1.3, 100baseTX ethernet
booting NetBSD-6.1.4 uncompressed kernel (netbsd) from local root disk: 25s
booting NetBSD-6.1.4 compressed kernel (netbsd.gz) from local root disk: 17m 30s
$ time gzip -d netbsd.gz
11.65 real 6.83 user 1.49 sys
netbooting NetBSD-6.1.4 Install System compressed
boot.6.1.4: 21m 30s
boot.4.0.1: fails
boot.matt: 2m 3s
netbooting NetBSD-6.1.4 Install System uncompressed
boot.6.1.4: 54s
boot.5.1.2: 58s
boot.4.0.1: fails
boot.matt: 60s
netbooting NetBSD-1.5.3 Install System compressed
boot.mop.1.5.3: 1m 34s
boot.6.1.4: 3m 23s
boot.5.1.2: 3m 27s
boot.4.0.1: 1m 27s
boot.3.1.1: fails
boot.2.1: fails
boot.matt: fails
It is interesting how poor the decompression speed is in boot for the
later releases.
The boot that I have been using for netbooting for the last 5 years or
so is boot.matt which I believe was supplied by Matt Thomas when the
boot included in release was broken. It looks like this was about the
same time that the decompress code in standalone boot transitioned
from lib/libz to net/zlib. It is clearly 10 times faster than in
6.1.4.
ftp://ftp.netbsd.org/pub/NetBSD/misc/matt/boot
Is it possible that the caches are not enabled during the
decompresssion? That might be tough due to per-implementation
differences, but if there's room in the boot code for that stuff, that'd
make a HUGE difference.