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Commit f191746c authored by Janakarajan Natarajan's avatar Janakarajan Natarajan Committed by Greg Kroah-Hartman
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perf/x86/amd/uncore: Get correct number of cores sharing last level cache 



In Family 17h, the number of cores sharing a cache level is obtained
from the Cache Properties CPUID leaf (0x8000001d) by passing in the
cache level in ECX. In prior families, a cache level of 2 was used to
determine this information.

To get the right information, irrespective of Family, iterate over
the cache levels using CPUID 0x8000001d. The last level cache is the
last value to return a non-zero value in EAX.

Signed-off-by: default avatarJanakarajan Natarajan <Janakarajan.Natarajan@amd.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: default avatarBorislav Petkov <bp@suse.de>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/5ab569025b39cdfaeca55b571d78c0fc800bdb69.1497452002.git.Janakarajan.Natarajan@amd.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 7bf707d1

arch/x86/events/amd/uncore.c

+16 −3
Original line number Diff line number Diff line
@@ -378,11 +378,24 @@ static int amd_uncore_cpu_starting(unsigned int cpu) 


	if (amd_uncore_llc) {

		unsigned int apicid = cpu_data(cpu).apicid;

		unsigned int nshared;

		unsigned int nshared, subleaf, prev_eax = 0;



		uncore = *per_cpu_ptr(amd_uncore_llc, cpu);

		cpuid_count(0x8000001d, 2, &eax, &ebx, &ecx, &edx);

		nshared = ((eax >> 14) & 0xfff) + 1;

		/*

		 * Iterate over Cache Topology Definition leaves until no

		 * more cache descriptions are available.

		 */

		for (subleaf = 0; subleaf < 5; subleaf++) {

			cpuid_count(0x8000001d, subleaf, &eax, &ebx, &ecx, &edx);



			/* EAX[0:4] gives type of cache */

			if (!(eax & 0x1f))

				break;



			prev_eax = eax;

		}

		nshared = ((prev_eax >> 14) & 0xfff) + 1;



		uncore->id = apicid - (apicid % nshared);



		uncore = amd_uncore_find_online_sibling(uncore, amd_uncore_llc);