topic Re: what bit-level am i running? in Operating System - Linux

what bit-level am i running?

joseph wholey — Tue, 02 May 2006 10:24:44 GMT

Can't seem to find a definitive answer to determine what bit-level my cpu is capable of, and what bit-level I'm running at. uname -a shows me the following:
Linux enycxdbitdw01 2.4.21-32.0.1.ELsmp #1 SMP Tue May 17 17:52:23 EDT 2005 i686 athlon i386 GNU/Linux

cat /proc/cpuinfo shows me this:
processor : 0
vendor_id : AuthenticAMD
cpu family : 15
model : 5
model name : AMD Opteron (tm) Processor 848
stepping : 10
cpu MHz : 2197.158
cache size : 1024 KB
physical id : 0
siblings : 1
runqueue : 0
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 1
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 syscall nx mmxe
xt lm 3dnowext 3dnow
bogomips : 4377.80

I'm looking for a spec sheet on the AMD Opteron Processor 848, but can not seem to find one. Any help?

Re: what bit-level am i running?

Mike Stroyan — Tue, 02 May 2006 10:46:40 GMT

All Opteron processors are capable of running with 64-bit pointers. The uname -a output shows that you are running a 32-bit i686 version of redhat enterprise linux 3 on that system. So it currently is using 32-bit pointers. You can confirm the current size of type long by running "getconf LONG_BIT". It will say 32 on that system. The size of long happens to match the size of pointer in linux on x86. (There is no architectural requirement that says "getconf LONG_BIT" will match the size of a pointer. Microsoft windows actually left long as 32-bits on systems with 64-bit pointers.)

Re: what bit-level am i running?

Steven E. Protter — Tue, 02 May 2006 10:49:38 GMT

Shalom Joseph,

Your processor may be 64 bit capable, but the OS is 32 bit.

uname -a

cd /boot/
do a what on the vmlinuz file you are booting off of.

My system does not have the what command, but if you examine the kernel you will see what mode you are booting into.

I'm guessing my brain locked and the what command is hpux.

SEP

Re: what bit-level am i running?

joseph wholey — Tue, 02 May 2006 10:50:40 GMT

Thanks for the info... one more thing. Why does uname -a show "athlon" processor and cat /proc/cpuinfo show "opteron" processor?

Re: what bit-level am i running?

Mike Stroyan — Tue, 02 May 2006 17:25:20 GMT

Redhat's version of uname is patched with code that specifically checks the /proc/cpuinfo vendor_id for "AuthenticAMD" and changes the "uname -p" processor field from "i686" to "athlon". That is obviously getting a little dated in the age of Opteron and Turion and Sempron processors.

The /proc/cpuinfo "model name" data is coming straight out of cpuid instructions. It passes on what the CPU says it is without preconceptions.

Re: what bit-level am i running?

Vipulinux — Wed, 03 May 2006 05:24:10 GMT

Hi

This is the command :

getconf WORD_BIT

This will give whether ur system is 32 bit or 64

Cheers
Vipul

Re: what bit-level am i running?

Mike Stroyan — Wed, 03 May 2006 09:26:15 GMT

Vipulinux,

"getconf WORD_BIT" is actually the number of bits in an int. It will return 32 on a linux system that has 64 bit pointers and longs. You need to use "getconf LONG_BIT".