Comparing buildworld times on twin machines

[Charles Howse]

> On Sunday 28 September 2003 01:28 pm, Charles Howse wrote:
> > > 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)
> 
> That would work but I run my buildworlds from a consol in KDE and I 
> don't see that much difference and running it with KDE 
> stopped. Running 
> it single user mode may be faster than shutting apache down. But then 
> you won't know what caused it to begin with. 
> 
> I have scripts in /root/bin to start and stop it and start 
> it. They are
> 
> # cat startapache
> #! /bin/sh
> /usr/local/sbin/apachectl start
> 
> # cat stopapache
> #! /bin/sh
> /usr/local/sbin/apachectl stop
> 
> >
> > > 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?
> 
> I think that performance would turn things on. You may have a 
> bad cache 
> but that isn't what I would look at first. Not all Celerons have the 
> same kind of cache. I gave a Celeron 433a, which had the on board 
> cache, to some friends that needed a computer. I had swapped 
> it out and 
> all the needed to do was buy a montior.
> 
> Using PC-100 memory is about 15% faster than PC-66 memory. 
> This was the 
> difference in accumulated wu processing time for seti on 2xx wus with 
> the different speed memory. Jumping up to PC-133 didn't change 
> anything. That is like getting a cpu upgrade for just a few 
> $s. A 128MB 
> pc-100 sdimm runs around $35 at Best Buy and you know you can 
> do better 
> than that off of the Internet.
> 
> > *Exactly* how do I watch the swap...in top?
> >
> 
> Watch top and see if something is forcing processes to swap 
> by watching 
> the swap line of information. 
> 
> You can also see if apache is accruing time while you do the 
> build. It 
> shows you the processes as they accrue time and which one is 
> getting a 
> lot of time is what you are looking for. You can't do this in single 
> user mode because you only have the console.

Very good, thanks for your input!