RE: [PATCH] hyper-threading information in /proc/cpuinfo

["Nakajima, Jun" <jun.nakajima@intel.com>]

Agree. We can calculate smp_num_siblings from phys_proc_id[n] as the kernel
does, although it would be just nice or double-checking (but if the
application cannot calculate it correctly how can one expect it runs fine? I
mean it's very easy.)

So this is sufficient:
+#ifdef CONFIG_SMP
+	if (cpu_has_ht) {
+		seq_printf(m, "physical id\t: %d\n", phys_proc_id[n]);
+	}
+#endif

For a multi-core system, one could do:

	seq_printf(m, "physical id\t: %d\n", phys_proc_id[n]);
	seq_printf(m, "core id\t: %d\n", core_id[n]);

This would support multiple SMT processor cores on one chip. "core_id" is
the id of the CPU core in a chip die that the processor belongs to.
"physical_proc_id" is the id of the CPU die in the system.

Jun
-----Original Message-----
From: Dave Jones [mailto:davej@codemonkey.org.uk]
Sent: Friday, October 25, 2002 5:13 PM
To: Jeff Garzik
Cc: Robert Love; Nakajima, Jun; Alan Cox; 'akpm@digeo.com';
'linux-kernel@vger.kernel.org'; 'chrisl@vmware.com'; 'Martin J. Bligh'
Subject: Re: [PATCH] hyper-threading information in /proc/cpuinfo


On Fri, Oct 25, 2002 at 08:04:45PM -0400, Jeff Garzik wrote:

 > Not really... we print out other information that is duplicated N times, 
 > because it is the common case that N-way systems have matched processors 
 > with matched capabilities.

Not really. We print out the 'duplicate' info because it's read that
way from different CPUs. The smp_num_siblings is a single global
variable. Theoretically, the other stuff /could/ change in an
asymetrical system, but the num_siblings thing is constant.
 
		Dave

-- 
| Dave Jones.        http://www.codemonkey.org.uk