Re: [Ngspice-users] Performance problems with Athlon 64 X2?

[Sergey S. <suk...@go...>]

Hi Bill,

I have two suggestions.
1. To make sure multithreading is implemented in ngspice.
There are two possibilities to implement mt mode:
 1.1. To divide evaluate function on the threads of machine;
 1.2. To divide netlist instances claculations on the threads.

2. With 64 bits it is predictable. CPU time is slower, BUT you have to look
at elapsed time.
Elapsed time should be faster.

Best,
--Sergey


On 5/11/07, John Brunhaver <jbr...@gm...> wrote:
>
> If your gcc flags are not set to take advantage of your specific
> architecture, you may be leaving performance on the table.
>
> Actually, the transition from executing 32-bit to executing 64-bit code is
> known in some memory intensive applications to cause a reduction in
> performance due to the increased size of memory addresses and payloads (all
> else being equal).  At least this was a subject another student at my
> University was pursuing casually and had shared with me a few months ago.
>
> However, I have never compiled for or simulated on an AMD machine.  I
> haven't run extensive simulations yet to compare the run times of 1 64-bit
> Intel core from a quad-core machine to 1 32-bit P4 thread. Or the comparison
> of 4-Cores to 2-Threads.
>
> I would also appreciate anyone's thoughts on this topic.
>
> On 5/10/07, Bill Richards <ric...@tb... > wrote:
> >
> > Hi-
> > I recently upgraded my simulation system from an old XP 1600+ box to an
> > Athlon 64 X2 3800+.  I grabbed the x86_64 ngspice package via yum, and
> > ran some test cases.  To my surprise, mt test cases ran SLOWER on my new
> > Athlon 64 box!!  Being somewhat paranoid of binary RPMs, I downloaded
> > the sources and necessary libraries and made it all from scratch.  Ran
> > the test cases, and again, the ngspice code on my new box yielded
> > exactly the same results as my old box, only over 2X slower!!!  Has
> > anyone encountered this kind of behavior with ngspice on an Athlon 64
> > box?
> > I don't have any other benchmarks to compare performance of this machine
> > against my now-defunct old machine.  Any help or suggestions would be
> > appreciated!
> > Thanks,
> > -bill-
> >
> > -------------------------------------------------------------------------
> >
> > This SF.net email is sponsored by DB2 Express
> > Download DB2 Express C - the FREE version of DB2 express and take
> > control of your XML. No limits. Just data. Click to get it now.
> > http://sourceforge.net/powerbar/db2/
> > _______________________________________________
> > Ngspice-users mailing list
> > Ngs...@li...
> > https://lists.sourceforge.net/lists/listinfo/ngspice-users
> >
>
>
> -------------------------------------------------------------------------
> This SF.net email is sponsored by DB2 Express
> Download DB2 Express C - the FREE version of DB2 express and take
> control of your XML. No limits. Just data. Click to get it now.
> http://sourceforge.net/powerbar/db2/
> _______________________________________________
> Ngspice-users mailing list
> Ngs...@li...
> https://lists.sourceforge.net/lists/listinfo/ngspice-users
>
>


-- 
Best,
--Sergey