[wlugkc] Re: SMP Thoughts
- From: Richard Eiken <raeiken@xxxxxxxxxxxxx>
- To: wlugkc@xxxxxxxxxxxxx
- Date: Thu, 19 May 2005 06:28:04 -0700 (PDT)
always interested. I will have to compile a new kernel
and time it to see what I get. Doesn't compile time
also depend on how many modules you select, or build
into the kernel?
-Rich.
--- Robert Gambrill <robertgambrill@xxxxxxxxxxxxx>
wrote:
> Hi All,
>
> Got some data on going to multiple CPU's using
> linux-2.6.8 kernel
> compiles as a benchmark.
>
> I setup the new mainboard using my old 2.6.8
> kernel, and redid the
> 'make menuconfig' to configure it for multiple
> CPU's. At this time I was
> running with one CPU enabled. Using....
>
> time sh -c 'make bzImage'
>
> ... I got aprox ~00:35:12 for the compile time.
>
> I then did a make modules_install and setup the new
> kernel in lilo.conf.
>
> Rebooted and verified that I had two CPU's running.
> Did another timed
> 'make bzImage' .
>
> I got approx ~ 00:18:27 for the two CPU
> compile time. It took
> about 52% of the time a single CPU would have
> taken. Thats about
> what I expected, there has to be some overhead to
> using more than
> one CPU. Still, It's a nice improvement.
>
> OK, Today I recieved an adaptec 2940 U2W SCSI
> Controller I ordered. This
> allows my Ultra 160 SCSI drives to talk at 80 MBs
> (Sync) on my 32bit PCI
> bus ( My old 2940 Ultra Wide could only do 40 MBs ).
> You gotta have
> PCI-Express (64-bit) to do Ultra 160 or Ultra 320.
>
> Anyway I doubled my harddrive's bandwidth and
> recompiled the kernel
> (same as before).
>
> I got approx ~00:18:05 for the compile time.
> Not much improvement
> (about 2%) but it showed up.
>
> SO!
>
> The Kernel compile is NOT I/O bound on my machine.
> It IS heavily CPU
> bound, and would ( in my entirely unscientific
> opinon) benefit from a
> set of newer CPU's. I imagine a lone modern CPU
> would
> probably stomp this old board into the ground. I
> only bought it to play
> with. I may upgrade the P3's to the max and see what
> happens. Thats the fun thing about junkbox gear, It'
> cheap to get the parts!
>
> Oh BTW, to do these tests you have to edit the make
> options. Make -jN
> where N equals the number of CPUs +1 allows it to
> use
> multiple CPU's.
>
> I would like to hear, if you think about it, how
> long to takes to
> compile your linux kernel on more modern equipment.
> Sorry, at this time
> the only test I have to check out S.M.P. is a kernel
> compile. Will try
> to see what improvement I get on doing something
> real world, oh
> say for example, MPEG encoding, and let you guys
> know if anybody's
> interested.
>
> Robert
>
>
>
>
>
>
>
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