Ubuntu 32-bit, 32-bit PAE, 64-bit Benchmarks

[Drago]

AFAIR when I switched on disk usage increased by ~25%. RAM usage increased by roughly the same amount.

But that was many many years ago

What do you mean "increased by same amount" ... 100% increase?
However, I am not concerned about system RAM usage. I am concerned about L1/L2 cache usage on my future Athlon II.

[energyman]

no, in memery increased by 25% too, if I remember correctly.

it will be roughly the same. Since data and commands are seperated in L1 at least data will not suffer.

Also, while you don't have L3 with Athlon II you will get a bigger L2 (except if you are coming from an old X2 6000). 1mb/core is not too bad. More than most old X2s. And the Athlon II Regor core is faster on the same clock than the old Kuma or Windsor/Brisbane. So.. don't worry too much.

[Drago]

1mb/core is not too bad. More than most old X2s. And the Athlon II Regor core is faster on the same clock than the old Kuma or Windsor/Brisbane. So.. don't worry too much.

These new Athlon IIs, have only 512KB/core, so I am worrying about it.
Maybe, I just should install arch i686 and x86_64 versions, and test it myself. So now I have to figure out how to run this PTS on my box
Do you know any other test suits, with..smaller disk footprint?

[FireBurn]

Using a car analogy (since we all love them)

We're going to compare 3 petrol types

Unleaded
Super Unleaded
Chemical X

but then not mentioning that Chemical X uses different engine components

Which isn't like for like

I guess it's difficult to compare these type of benchmarks when the target hardware is so different

The best way to compare would be to compile using -march=native on a 32bit and 64bit environment keeping as much the same as possible

Then testing pure 32bit, pure 64bit and 32bit with 64bit kernel

I currently have two gentoo systems set up like this would anyone be in
me making some benchmarks for a core2 + GM45 system and a athlon X2 + Radeon 4650?

[Dragoran]

What do you mean "increased by same amount" ... 100% increase?
However, I am not concerned about system RAM usage. I am concerned about L1/L2 cache usage on my future Athlon II.

It is higher but you should take into account that the fastest "memory" available are the cpu registers, and you have twice as many when running 64bit code.

Also you need less instructions to do the same tasks, and function parameters are passed via registers rather than via stack.

So it should be a net gain for most applications.

[energyman]

These new Athlon IIs, have only 512KB/core, so I am worrying about it.
Maybe, I just should install arch i686 and x86_64 versions, and test it myself. So now I have to figure out how to run this PTS on my box
Do you know any other test suits, with..smaller disk footprint?

the dual core have 1mb/core. The quad have 512kb/core L2. But as several sites have found out, no L3 does not hit the Athlon II too hard. The quad Athlon II are the fastest procs in their prize range.

You loose a lot of performance if you go 32bit (to conserve cache) by loosing half of your registers. And registers are the stuff you really want to have.

[Ant P.]

x86-64 CPUs don't actually store everything in 64 bits, that would be stupid and wasteful.

 ~ $ cat /proc/cpuinfo | grep sizes
address sizes	: 48 bits physical, 48 bits virtual

[Drago]

the dual core have 1mb/core. The quad have 512kb/core L2. But as several sites have found out, no L3 does not hit the Athlon II too hard. The quad Athlon II are the fastest procs in their prize range.

I am up to Athlon II 435, tripple core with 1.5MB cache total. But may change my mind, if you make me. I am a developer and compilation will be common task. Also how eclipse, and java respect >2 cores?

[Dragoran]

x86-64 CPUs don't actually store everything in 64 bits, that would be stupid and wasteful.

 ~ $ cat /proc/cpuinfo | grep sizes
address sizes	: 48 bits physical, 48 bits virtual

That is what is present in hardware, the ISA does use 64bit pointers and therefore all pointers are 64bit.

And no that is not "stupid and wasteful", also early x86_64 cpus could only address up to 40bit of memory (1TB)

[leif81]

I'd be interested in seeing a java app in your future benchrmarks (one running in a 32bit JVM vs 64bit JVM).