linux and quad core

[mikekazik1]

I've been looking into linux during the past few months, but I have not been able to find this piece of info anywhere. Do any of you know if there is a distro of linux that can FULLY utilize all four cores in a quad core processor in addition to being able to utilize 8gb ram?

 

[linux_0]

Practically all of them can.

64bit Linux can support at least 64 CPUS!

128GB of RAM and 16TB per ext3 filesystem

What are you going to use this system for?

 

[mikekazik1]

The reason why I asked is so that I would know if linux can handle hi-def dvd encoding. You see, at this point in time, a standard avi file is about 700mb. When it is converted to dvd format, it takes up a little over 4 gigs. On my single core pc (you can check my system specs in the profile I have) it takes 4 hours to do that. However, all of the major companies like sony, toshiba, microsoft, etc are switching over to high capacity discs (the two kinds are called hd dvd and blu-ray). In order to convert a regular hi def video files into dvd format, you will need a heck of a lot of processing power. I would be lucky if I could do such a thing on my computer in a 24 hour period.

 

[MU_Engineer]

The reason why I asked is so that I would know if linux can handle hi-def dvd encoding. You see, at this point in time, a standard avi file is about 700mb. When it is converted to dvd format, it takes up a little over 4 gigs. On my single core pc (you can check my system specs in the profile I have) it takes 4 hours to do that. However, all of the major companies like sony, toshiba, microsoft, etc are switching over to high capacity discs (the two kinds are called hd dvd and blu-ray). In order to convert a regular hi def video files into dvd format, you will need a heck of a lot of processing power. I would be lucky if I could do such a thing on my computer in a 24 hour period.

Linux can sure handle video encoding. I use dvd::rip and it will run on as many cores as you have (provided you check the box to split the video into pieces for transcoding), and even farm itself out to other computers and use them to assist. I was using four cores to transcode video with dvd:rip not all that long ago (two locally on the DT, two on my laptop).

@linux_0: All of the 2.6 Linux kernels I've compiled support up to 256 CPUs/cores, not 64. It can also support a full 16 EB RAM as the 64-bit addressing allows.

 

[linux_0]

Yes, you're right

I was being overly cautious.

I did check the kernel source before I replied which is why I said 64bit Linux can support at least 64 CPUS! since that was the number I was able to confirm during my initial search although I didn't find it in the code.

While it is true the kernel can support 256 CPUs, most architectures cannot.

The kernel can be extended while most architectures are often limited by hardware design and physical restrictions.

In the source they apparently set MAX_CPUS to 32 for PPC and 16 for voyager.

include/asm-ppc/residual.h

#define MAX_CPUS 32 /* These should be set to the maximum */#define MAX_MEMS 64 /* number possible for this system. */#define MAX_DEVICES 256 /* Changing these will change the */#define AVE_PNP_SIZE 32 /* structure, hence the version of */#define MAX_MEM_SEGS 64 /* this header file. */



include/asm-i386/voyager.h

/* The following structures and definitions are for the Kernel/SUS
* interface these are needed to find out how SUS initialised any Quad
* boards in the system */

#define NUMBER_OF_MC_BUSSES 2
#define SLOTS_PER_MC_BUS 8
#define MAX_CPUS 16 /* 16 way CPU system */
#define MAX_PROCESSOR_BOARDS 4 /* 4 processor slot system */
#define MAX_CACHE_LEVELS 4 /* # of cache levels supported */
#define MAX_SHARED_CPUS 4 /* # of CPUs that can share a LARC */
#define NUMBER_OF_POS_REGS 8



For MIPS they set it to 128 and 256.


include/asm-mips/sn/sn0/arch.h:#define MAXCPUS 128
include/asm-mips/sn/sn0/arch.h:#define MAXCPUS 256


The maxcpus bootparam allows you to specify the number of CPUs at boot time however I do not believe you can override the #define.