Now that dual-core processors are taking part of the market (specially those running WinXp Media Center), do you think Linux is really prepared to take advantatge of those dual-core processors?
AFAIK, to take full advantatge of it (assuming you don't do heavy multitask) the program(s) you're running must have to split into several threads so each core takes one of the threads. Do Linux apps behave like this? If not, how long we will wait until we cas ee this?

I think this is a really crucial question to those who are planning to upgrade their systems to get something better. Nobody wants to spent more money on something they won't take advantatge of.

Replies welcomed

Well right now, I'm content with how they function and I will expect that once we see more and more dual core pc's in the market, that a lot more software support will come.

I currently use an AMD 64 X2 3800(2.0ghz) and I run VMware inside linux to run Windows XP. It allows me to use both operating systems without seeing any slow down.

I've been running the SMP release of Fedora Core for a couple of years now, on a Intel "Hyperthread" 686, and I've had no problems. "GLrellM" shows it as a 2-processor system, and many applications just use one, but the kernel does a good job of distributing the load.

It is still true that most of the workloads that are actually presented to a computer are I/O-bound, not CPU-bound. (That terminology simply means that the primary thing "slowing down" the process, or determining its rate of execution, is the speed with which it can perform I/O, not the speed of the CPU.) If you graphed the CPU-utilization of your system over time, it might be 98% idle most of the time.

Given such workloads, full utilization of dual-core systems might never come about. Especially if the motherboards containing these sexy chips continue to have indifferent, EIDE-based I/O channels. But that won't stop the chip-makers from building them; it won't stop customers from demanding them and buying them in large numbers...

As for "can Linux handle it" ... most of the test-bed systems that chip makers use for testing are based on ... Linux. Most of the CPU-intensive <=>CENSORED<=> work that is being done on these systems is being done in ... Unix and Linux.

I would say most of the workloads present on a computer are neither I/O bound, nor CPU bound, but really "user" bound, so really not bound at all.

When the computer is really the bottleneck, I don't agree I/Os are mostly in cause, it really depends on what task(s) the server or the desktop is executing, and the CPU is often 100% for long periods on many machines.

Let me add a comment from a professional application. Where I work, we are using Red Hat Enterprise to run a very large database on a box with dual Xeon processors. The OS sees it as eight processors (four cores, each hyperthreaded) and acts accordingly. Although not every distribution has this capability, I believe Linux is up to the task.

short answer -- YES
long answer -- Linux can support something like up to 32 CPUs
and has special support for dual core so the non apropriate concepts for multiple cpus are not used for dual core. Different processes and kernel-threads are distributed among different processors. Single User-space threads are not. Threads are like processes in Linux following the general principle of no unique cases. With the exception of info shared with parent process. As far a parallel threading in applications -- i think programmers do this where they feel it is apropriate and do not or should not think about dual core machines or machines with many processors. There are limitations on the usefullness of dual core or multiple processor machines in a limited workload or single task environment for various reasons. they are cool and help -- i like them -- but we can't or really shouldn't expect application developers to change threading style or underlying reasons for threading because of what might turn out to be a marketing fad. Or we break portability and the general rule of NO SPECIAL CASES.

Linux runs on so many hardware... Hardware is not relevant anymore. You can run linux on a fridge if you feel like it.
Dual-core processors are of course supported by linux, more than any other system. Maybe some applications like freecell don't take advantage of some special features of your hardware, but who cares? A 386 machine is already too fast for freecell. For more power consuming applications, like The Gimp or Blender, of course multiprocessor or dual-core is supported and OpenGL is designed for that. You can run those applications in a clustered environment, or in a multi-processor or a dual core environment and take the full advantage of it. And if you find that the critical application you need isn't optimized for dual-core, and that application is open-source, you can do it yourself.

I know linux supports multi processor. but isn't dual-core is different architecture? I think the OS will still recognise the dual-core processor as a single processor instead of double.



http://www.alllinuxcd.com
262 distributions-platform combinations and counting.....

Dual core is supported natively, I can assure you that as I have both my cores running and have made very good use of both of them.

I have an Athlon 64 X2 3800 + and it's been great with gentoo

Some applications are threaded and some arent, but if you are a multi-tasker you can still get good benefit out of dual core.

To answer the original question, as well as any other OS. There is almost no consumer software at present written specifically to take advantage of dual-core (or 64-bit for that matter). The software guys have a lot of catching up to do.

I am a bit ignorant about dual core technology. What benefit dual dual core bring? In terms of memory addressing and threading, what kind breakthrough can dual core offer to software builders?



http://www.alllinuxcd.com
262 distributions-platform combinations and counting.....

Dual-core is essentially two CPU's closely interconnected in a single chip.

The technology is not limited to two cores, servers with the new UltraSPARC T1 CPUs having up to eight cores, and 4 threads per core were launched yesterday.

At the software level, this appears like a 32 CPUs machine.

The hardware is planned to be open source too:

http://opensparc.sunsource.net/nonav/index.html

exactly what would this take to "catch up" ?

software design is a complex thing that has always attempted from the very beginning to make the most of resources. I'm not going to go into software threading issues because the concepts are HUGE but statements like the one above are born straight out of corporate propaganda machine and nothing else.

This kind of crap is based in fact the same way everything donald rumsfeld says about some made up terrorist villian is based on facts.
It's just marketing bull designed specifically to contain no real information whatsoever accept "buy my thing i'm selling".

Nope, as long as you're running an SMP kernel, then your Dual-Core cpu will display as 2 separate processor units.

cpu 0: AMD Athlon(tm) 64 Dual Core Processor 3800+
cpu 1: AMD Athlon(tm) 64 Dual Core Processor 3800+

There you have it.