On Aug 17 08:27, Achim Gratz wrote:
> Achim Gratz <Stromeko <at> nexgo.de> writes:
> > The output is correct now for a SandyBridge dual-core CPU with
> > logical processors (aka HT) and an IvyBridge dual-core CPU w/o HT.
> 
> Another IvyBridge dual-core w/ HT looks also correct.
> 
> However, for the Piledriver Opteron 6328 in the 2012R2 server, Cygwin
> reports 8 cores.  Linux on the other hand would report 8 processors on 4
> cores (SMT, like HT on Intel).  I don't know where you get the topology
> information from,

The code is loosly based on what the Linux kernel does, combined with
the information given in

http://wiki.osdev.org/Detecting_CPU_Topology_%2880x86%29

So on AMD the topo is taken from cpuids 0x80000008 and 0x00000001,
but I may have made a mistake there.

[...digging...]

Oh, ok.  It seems I accidentally dropped a piece of code there.  Can you
do me a favor and run the following test application?  I just need the
value your Piledrive CPU returns in ecx returned by cpuid 0x80000008:

========================================================================
#include <stdio.h>
#include <stdint.h>

static inline void __attribute ((always_inline))
cpuid (uint32_t *a, uint32_t *b, uint32_t *c, uint32_t *d,
       uint32_t ain, uint32_t cin)
{
 asm volatile ("cpuid"
               : "=a" (*a), "=b" (*b), "=c" (*c), "=d" (*d)
               : "a" (ain), "c" (cin));
}

int
main ()
{
  uint32_t eax, ebx, ecx, edx;

  cpuid (&eax, &ebx, &ecx, &edx, 0x80000008, 0);
  printf ("0x80000008    %08x %08x %08x %08x\n", eax, ebx, ecx, edx);
}
========================================================================


Thanks,
Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Maintainer                 cygwin AT cygwin DOT com
Red Hat