Re: Intel P6 vs P7 system call performance

GrandMasterLee
2002-12-14T00:48:50Z

On Fri, 2002-12-13 at 10:49, Mike Hayward wrote:
> Hi Bill,
>
> > On Mon, Dec 09, 2002 at 01:30:28AM -0700, Mike Hayward wrote:
> > > Any ideas? Not sure I want to upgrade to the P7 architecture if this
> > > is right, since for me system calls are probably more important than
> > > raw cpu computational power.
> >
> > This is the same for me. I'm extremely uninterested in the P-IV for my
> > own use because of this.
>
> I've also noticed that algorithms like the recursive one I run which
> simulates solving the Tower of Hanoi problem are most likely very hard
> to do branch prediction on. Both the code and data no doubt fit
> entirely in the L2 cache. The AMD processor below is a much lower
> cost and significantly lower clock rate (and on a machine with only a
> 100Mhz Memory bus) than the Xeon, yet dramatically outperforms it with
> the same executable, compiled with gcc -march=i686 -O3. Maybe with a
> better Pentium 4 optimizing compiler the P4 and Xeon could improve a
> few percent, but I doubt it'll ever see the AMD numbers.
What GCC were you using? I'd use 3.2, or 3.2.1 myself with
-march=pentium4 and -mcpu=pentium4 to see if there *is* any difference
there. On my quad P4 Xeon 1.6Ghz with 1M L3 cache, I can compile a
kernel in about 35 seconds. Mind you that's my own config, not
*everything*. On a dual athlon MP at 1.8 Ghz, I get about 5 mins or so.
Both are running with make -jx where X is the saturation value.

> Recursion Test--Tower of Hanoi
>
> Uni AMD XP 1800 2.4.18 kernel 46751.6 lps (10 secs, 6 samples)
> Dual Pentium 4 Xeon 2.4Ghz 2.4.19 kernel 33661.9 lps (10 secs, 6 samples)
>
> - Mike
> -
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--
GrandMasterLee <masterlee@digitalroadkill.net>