Re: Call for PRs: nullfs

On Fri, Jul 16, 2004 at 01:08:48PM -0700, Julian Elischer wrote:
> I'm using nullfs for jails on -4.8(ish) without problems so far..

I find the performance of nullfs somewhat lacking as measured in the test
described below (a config with nullfs performs worse (~2x slower) than the same
config with vnodefs). For simplicity the test was done in chroot, doing it in a
jail has no significant impact on performance.

Hardware/OS:
------------
FreeBSD 5.2.1-RELEASE-p4 #1: Fri Apr  9 09:09:06 PDT 2004
CPU: Intel Pentium III (701.59-MHz 686-class CPU)
  Origin = "GenuineIntel"  Id = 0x683  Stepping = 3
  Features=0x387f9ff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,PN,MMX,FXSR,SSE>
real memory  = 268173312 (255 MB)
atapci0: <Intel PIIX4 UDMA33 controller> port 0xffa0-0xffaf at device 7.1 on pci0
ad0: 38166MB <WDC WD400JB-00ENA0> [77545/16/63] at ata0-master UDMA33

Config common:
--------------
/var/tmp/world:
populated with 'cd /usr/src; make installworld DESTDIR=/var/tmp/world'

/var/tmp/jail:
bin_at_ -> ro/bin
dev/
etc/
lib_at_ -> ro/lib
libexec_at_ -> ro/libexec
ro/
root/
sbin_at_ -> ro/sbin
tmp/
user/
usr/
var/

/var/tmp/jail/usr:
X11R6/
bin_at_ -> ../ro/usr/bin
include_at_ -> ../ro/usr/include
lib_at_ -> ../ro/usr/lib
libexec_at_ -> ../ro/usr/libexec
local/
ports/
sbin_at_ -> ../ro/usr/sbin
share_at_ -> ../ro/usr/share

Config vnodefs:
---------------
$ mdconfig -l -u md2
md2     vnode   131072 KBytes
$ mount | grep /var/tmp/jail
devfs on /var/tmp/jail/dev (devfs, local)
/dev/md2 on /var/tmp/jail/ro (ufs, local, read-only)
/usr/ports on /var/tmp/jail/usr/ports (nullfs, local, read-only)

Config nullfs:
--------------
$ mount | grep /var/tmp/jail
devfs on /var/tmp/jail/dev (devfs, local)
/var/tmp/world on /var/tmp/jail/ro (nullfs, local, read-only)
/usr/ports on /var/tmp/jail/usr/ports (nullfs, local, read-only)

Test:
-----
chroot /var/tmp/jail
cd /usr/ports/lang/perl5; time make WRKDIRPREFIX=/tmp

Numbers:
--------
nullfs:  176.257u 38.316s 6:04.13 58.9%  2801+2353k 183+366io 76805pf+0w
vnodefs: 173.918u 33.775s 3:36.65 95.8%  2845+2407k 303+339io 251pf+0w
base(*): 174.084u 33.281s 3:37.30 95.4%  2843+2415k 329+358io 252pf+0w

(*) This was a simple 'cd /usr/ports/lang/perl5; time make'

-- 
Alex.