Comparing buildworld times on twin machines

[Kent Stewart]

On Sunday 28 September 2003 12:37 pm, Charles Howse wrote:
> Hi,
> I have 2 machines on my home network with (almost) identical
> hardware. They both have Celeron 300, same motherboards, same BIOS,
> same options set in BIOS, etc.
> Same make.conf, same kernel config.
> I kill SETI at home before starting on each machine.
> The only difference is that curly has 128 MB ram where larry has only
> 64.
>
> They *do not*, however have identical hard drives, even though each
> machine has 2 drives, with /usr/obj on the second drive of each
> machine.
>
> When I buildworld, I use the following command, and write the output
> to '$blog'.
>
> [portion of script omitted, entire script is attached as update1.sh]
>
> \time -aho $$blog make buildworld
>
> [snip]
>
> Larry can buildworld in 1 hr 57 mins.
> It takes curly 3 hrs 16 mins, even though curly has twice the ram.
>
> If I watch the compile, with one eye on the disk activity light, it
> seems to me that the process is largely CPU intensive, therefore I
> would expect that the buildworld times should be roughly equal.
>
> 1) How can I determine what might be causing curly to take so long
> compared to larry?
>
> 2) Since curly runs httpd, and vsftpd, is it acceptable to run the
> entire build/install process in single-user mode in order to prevent
> other processes from eating CPU cycles?
>
>

On my systems, which all run setiathome, I only see a few percent 
variation in buildworld time with seti running. I start setiathome with 
a -nice 19 so that it doesn't interfere.

You might be able to see some of the processes running using top. You 
could always stop apache.

My setup has /usr/src and /usr/obj on a 2nd and 3rd hd and I log 
everything to the 1st HD.. All of the HDs are on their own controller 
and they are ata-133's on the main system. A system with ata-66s is not 
50% slower.

I kind of wonder if you have cache turned on in the cpu. That much 
difference is pretty hard to come up with unless your 2 daemons are 
interfering. You might see that running top. Watch the swap to see if 
anything is happening.

FWIW, I had one system with everything identical but the mobos and one 
ran 15% slower than the other. I never did figure out what was causing 
the difference. It is my only 400MHz machine and only use it for some 
special programs.

Kent

-- 
Kent Stewart
Richland, WA

http://users.owt.com/kstewart/index.html