From ab027620e95987b5f0145013090a109b4152d23b Mon Sep 17 00:00:00 2001 From: Janakarajan Natarajan Date: Wed, 14 Jun 2017 11:26:58 -0500 Subject: [PATCH] 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: Janakarajan Natarajan Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Borislav Petkov Cc: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Suravee Suthikulpanit Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/5ab569025b39cdfaeca55b571d78c0fc800bdb69.1497452002.git.Janakarajan.Natarajan@amd.com Signed-off-by: Ingo Molnar --- arch/x86/events/amd/uncore.c | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) diff --git a/arch/x86/events/amd/uncore.c b/arch/x86/events/amd/uncore.c index e34f8a6b4440..f5cbbba99283 100644 --- a/arch/x86/events/amd/uncore.c +++ b/arch/x86/events/amd/uncore.c @@ -400,11 +400,24 @@ 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); -- 2.20.1