On 5/3/07, Kris Kennaway <[EMAIL PROTECTED]> wrote:
On Thu, May 03, 2007 at 02:39:55AM +0800, Mars G. Miro wrote:
> Greetz,
>
> I got my hands on a SunFire x4600. This is a dual-core 8-way
> Opteron (dmesg shows 16 CPUs) w/c has 32G RAM. FreeBSD 6.2/amd64 runs
> fine on it despite:
> - 'reboot' doesnt work, machine just hangs in there.
There is a sysctl to specify an alternate reboot method.
> - front USB ports wont work for a USB keyboard, just use da ports at da
> back.
>
> I've read a lot of threads in da past (and da BSDCan 2006 paper)
> regarding mfs on /usr/src and /usr/obj to speed up buildworlds,
> unfortunately it doesnt seem to improve things. I've tried both a
> malloc and swap based async non-softupdates mfs (and rebooted da box
> every after) but my buildworld speeds seem to be just da same as I do
> it on da MPT SAS disk w/c is just around ~18mins.
It is probably a combination of issues:
1) There is still some disk access because of accessing things like
binaries in /usr. This will hurt more for parallel builds because
your disk hardware is single-threaded, so I/O delays will serialize
you. If you really wanted you could compare to a build in a md-hosted
chroot to completely eliminate the disk, but this is just a game.
2) Buildworld doesn't parallelize well to 16 CPUs. Large parts of it
are completely non-parallel. This is probably your main problem.
I guess that might explain it, see more below...
You definitely should be measuring some difference - you need to use
time(1) though instead of just estimating.
I did use time, here:
make -j32 buildworld:
disk
3229.975u 8981.269s 18:55.21 1075.6% 3804+2164k 19702+6594io 2158pf+0w
malloc mfs ( mdmfs -SM -o async,noatime -s 2G md {src, obj} )
3069.783u 9546.250s 18:57.58 1109.0% 3844+2147k 18504+4422io 2628pf+0w
swap mfs ( mdmfs -S -o async,noatime -s 2G md {src, obj} )
3061.682u 9682.776s 19:08.90 1109.2% 3849+2164k 13732+4402io 2053pf+0w
make -j16 buildworld:
disk
3218.722u 7855.885s 17:42.26 1042.5% 3833+2267k 16995+6620io 2445pf+0w
malloc mfs ( mdmfs -SM -o async,noatime -s 2G md {src, obj} )
3187.753u 8199.049s 17:57.63 1056.6% 3839+2238k 6890+4436io 2346pf+0w
swap mfs ( mdmfs -S -o async,noatime -s 2G md {src, obj} )
3200.400u 8213.312s 18:06.88 1050.1% 3860+2243k 12800+4397io 2303pf+0w
Kris
Thanks
cheers
mars
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