/proc/cpuinfo

Wed May 7 23:29:00 GMT 2003

Chris January writes:
 > > The MPlayer documentation maintainer with shameless requests again ;-)
 > >
 > > I have a few questions about /proc/cpuinfo.
 > >
 > > On my machine I get the following output under Cygwin:
 > >
 > > processor : 0
 > > vendor_id : AuthenticAMD
 > > type : primary processor
 > > cpu family : 5
 > > model : 13
 > > model name : AMD-K6(tm)-III Processor
 > > stepping : 0
 > > brand id : 0
 > > cpu count : 0
 > > apic id : 0
 > > cpu MHz : 250
 > > fpu : yes
 > > flags : fpu vme de pse tsc msr mce cx8 pge mmx
 > >
 > > which differs a bit from the output under Linux:
 > >
 > > processor	: 0
 > > vendor_id	: AuthenticAMD
 > > cpu family	: 5
 > > model		: 13
 > > model name	: AMD-K6(tm)-III Processor
 > > stepping	: 0
 > > cpu MHz		: 501.121
 > > cache size	: 256 KB
 > > 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 mce cx8 pge mmx syscall
 > > 3dnowext 3dnow k6_mtrr
 > > bogomips	: 999.42
 > >
 > >
 > > The 250MHz under Cygwin are probably a bug, I have a 500MHz CPU.
 > This value is taken from the Windows registry. Linux calculates it from
 > scratch it during its BogoMIPS initialisation. Have a look in your Windows
 > System control panel and you should see the same incorrect value.
As I said, it's a bug, but in Windows not in Cygwin ;-)
 > > The interesting field is flags, which we use in our configure script
 > > to check for processor capabilities and later optimize for the ones we
 > > find. Cygwin detects/displays less flags than Linux:
 > >
 > > flags : fpu vme de pse tsc msr mce cx8 pge mmx
 > > flags		: fpu vme de pse tsc msr mce cx8 pge mmx syscall
 > > 3dnowext 3dnow k6_mtrr
 > >
 > > This is a pity as I now loose 3dnow and mtrr optimizations without
 > > manual tweaking.
 > >
 > > I know that /proc/cpuinfo is very new on Cygwin. Is the lack of some
 > > flags a bug, or is this just implemented in a different way. Any
 > > chance of supporting those flags in the future?
 > >
 > > If somebody decides to extends /proc/cpuinfo that would be
 > > tremendously appreciated. I'm not expecting anything, of course, just
 > > hoping.
 > I used the Intel list of flags, but the list is slightly different on AMD
 > (e.g. 3dnow). If you can find and send me a list of the cpuid features flags
 > for AMD processors I'll add this in.
I'll try to come up with something, expect to hear from me soon.
Thanks
Diego
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