FreeBSD on the Athlon64 in 64bit vs Pentium4 3.2E

veliath writes "Came by a comparison from about three weeks ago, between two systems running FreeBSD. One is an Athlon64 running FreeBSD in 64bit mode and the other a Pentium4 3.2E running FreeBSD in 32bit mode."

Comments

Re:What about multiple processors?

[Homology]

When I run top, it sure is nice to every now and then see 2 processors at almost 100% utilization, yet also show 50% idle.

It shows that you have capacity over for starting other processes. It also shows that your system is slower that it could be. Some food for thought relating to the uses of hyperthreading.

Re:AMD 3200 won with only 512k cache.

[Too Much Noise]

I think you're mistaking the Athlon64 3200+ for the 3000+. 3200+ has 1M cache, while 3000+ has 512k. 3400+ has the same 1M cache, plus the 0.2GHz speed bump.

Come to think of it, this can actually be found on the very page you linked to.

Re:HT & threads

[ratboy666]

What HyperThreading is...

Out of order execution takes the processor to a particular level of performance. Unfortunately, (and especially with the X86 IA), we run out of steam rather quickly, and the processor blocks waiting on registers or memory. The idea behind HT is that the processor's execution elements can then be reassigned to something else waiting in cache.

Of course, this means we need a big fat cache, and something else to execute. Could be another thread or process, but the important thing is that the second job be independent.

This can increase the utilization of the processor's compute elements.

So, yes, the "builds with multiple jobs running at the same time" test makes sense.

I would like to see a benchmark with CPU stalls and utilization summarized at the end. Can't do it myself, because I am far too cheap to replace my current system (and yes, it is an MP box - dual 200Mhz PPRO - and it still does quite nicely).

Anyway, it does look the the Intel took a hit in this benchmark; too bad for them. I looked over the methodology -- and it looked reasonable given the scope of the project.

Ratboy.

Re:Ultimate 64 bit Nethack box!

[Henry V .009]

So sad to see that the parent is yet another victim of the megahertz myth.

Imagine for a moment that a CPU maker created a chip that performed 10 times the number of operations per cycle that either Intel or AMD could achieve. But also imagine that because of the complexity, they could only get the chip to run at 50MHz. Not very useful, huh?

Intel has gone with a design that allows them to ramp up clock speed. AMD has gone with a design that allows them to use clock cycles more efficiently.

Both of those approaches are a perfectly good way to do things. All that matters is how fast the user's applications run in the end.