Other Leopard Improvements: Multicore Support

[ChildOL]

as i'm developing a multithreaded application myself at work, i know, how hard it is, to use multiple cores efficiently. often, it doesn't make sense to split work up into more then two threads. many benchmarks showed that the 8 core mac pro wasn't nearly twice as fast as the quad.
the biggest problem with os 10.4 on my 2ghz imac g5 is imo a very slow adobe flash player. watching youtube videos often result in over 90% cpu usage.
compared to windows machines i have, this is unbelievable slow.
maybe with multicore macs this changes, or has changed?

I have the same issues with flash and wish Adobe would optimize Flash and release a "better" version.

 

[ChildOL]

"...A new multithreaded network stack speeds up networking by handling network inputs and outputs in parallel..."

So, uh, does this mean transferring files is faster and uses LESS system resources? That would be great if that means when I am downloading files it doesn't slow down the UI etc.

Interesting, though, since I "thought" Tiger was all threaded etc. and already took advantage of multiple CPUs, I think I am a little confused lol

 

[Amdahl]

Dude, Apple has lots and lots and lots and lots of cash. 8-core Mac Pros have NOTHING to do with Apple Inc.'s solvency. Seriously how could you not realize that?

In case you hadn't noticed, Wall Street doesn't care about what has already been made. They want to know what you've done recently.

 

[Amdahl]

"...A new multithreaded network stack speeds up networking by handling network inputs and outputs in parallel..."

So, uh, does this mean transferring files is faster and uses LESS system resources? That would be great if that means when I am downloading files it doesn't slow down the UI etc.

Within limits, it might help you; what it means is that more than one CPU can be running network code. I don't think you'll notice much gain from this in web browsing, but if you do local LAN copying or have an Xsan, there may be some bigger benefits. Same deal with the fact that the autofs filesystem code is able to run on more than one CPU at a time.

In Tiger, only one CPU could be executing OS code OF ANY KIND (except for the Mach microkernel itself). If the CPU was busy doing network code, no file system code could run. And so on for any subsystems that haven't been 'broken down.' We know that OpenGL, Network, and Filesystem have been broken down to run on multiple CPUs at once in Leopard. This was called the Giant lock in FreeBSD 4. In the development of FreeBSD 5, the Giant lock was whittled back so that it covered fewer subsystems, and then each of those subsystems was given the ability to multithread. (I think that is technically called 'being re-entrant.')

Interesting, though, since I "thought" Tiger was all threaded etc. and already took advantage of multiple CPUs, I think I am a little confused lol

That was the big lie! The improvements from Panther to Tiger in SMP support were very small. Most of the system continued to be single threaded and to run poorer as you added cores. That's why the quad-core is able to BEAT the 8-core on some specific types of benchmarks.

 

[guzhogi]

I wonder how much of a difference it would make if ALL software (apps AND OS) were optimized for multi-core computers, and 64-bit ones at that. While somethings won't make much difference (like a basic calculator program doing 2+2), using multiple programs or even a single multi-threaded app would see great benefits if everything was optimized for multiple cores. Remember, there's no advantage to having a multi-core computer if you run single threaded apps at a single time. Only time having multiple-cores would help then is if you're running multiple single-threaded apps. So if running only 1 single-threaded app, it'll go faster on a 3 GHz single core comp than a 2 GHz multi-core comp.

I've been tempted to create my own programming language and then an OS using that language that's totally optimized for 64-bit multi-core systems. Unfortunately, I don't have the know-how to do so. Besides, by the time I'd be finished, we'd have 256-bit 65,536 core systems. Just interested to see how efficient today's software actually is.

 

[dartzorichalcos]

Is the G5 a 64bit processor? - will that benefit from the 64bit nature of leopard?

More information about the G5 processor here. So yes, the G5 is a 64-bit PPC processor.