Comparing buildworld times on twin machines

[Charles Howse]

> 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.

Me, too.

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

True, I could do that, but what is your opinion on running the entire
build/install process from single-user mode? (my original question)

> 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.

Oh, geeeez, technical stuff!  ;-)  I'm a real dumbass in the BIOS.  I
just select "Load High Performance Settings" on each machine, and then
change the boot order to my liking.
I did notice that 'internal cache' is set to 'write-back'.
Am I on the right track?  
*Exactly* how do I watch the swap...in top?