Messages in this thread | | | Subject | Re: [RFC PATCH] perf/x86/intel/rapl: avoid access unallocate memory | From | "Charles (Chas) Williams" <> | Date | Tue, 8 Nov 2016 09:57:19 -0500 |
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On 11/08/2016 09:31 AM, Thomas Gleixner wrote: > On Tue, 8 Nov 2016, Charles (Chas) Williams wrote: >> [ 0.016335] topology_update_package_map: apicid 0 pkg 0 cpu 0 >> [ 0.016398] smpboot: APIC(0) Converting physical 0 to logical >> package 0, cpu 0 (ffff88023fc0a040) >> [ 0.016399] topology_update_package_map: apicid 1 pkg 1 cpu 1 >> [ 0.016462] smpboot: APIC(1) Converting physical 1 to logical >> package 1, cpu 1 (ffff88023fd0a040) >> >> So, I don't know where apic->cpu_present_to_apicid(cpu) is getting its >> apicid but it certainly doesn't seem to the match the apicid in the >> CPU's registers. For whatever reason, my VMware system is reporting >> that the second CPU has a local APIC ID of 2: > > The initial information comes from MP tables or ACPI. > >> [ 0.009115] identify_cpu: cpu_index 0 phys_proc_id is now 0, >> apicid 0, initial_apicid 0 >> ... >> [ 0.237401] identify_cpu: cpu_index 1 phys_proc_id is now 2, >> apicid 2, initial_apicid 2 > > And the CPUID emulation tells something different. Sigh! > >> I was thinking it might be better to call topology_update_package_map() >> at the bottom of identify_cpu() to setup the secondary CPU's. The boot >> cpu could be setup during smp_init_package_map(). > > Perhaps, but that does not make the inconsistencies go away....
By the time I know it's not consistent, there isn't anything I can do about it. I can't update the table to remove the bad information.
The other alternative, is to trust the ACPI and just update the cpu_data's apicid in identify_cpu() to the value from the table. The earlier kernels didn't seem to rely as much on this information. But it does appear to be "wrong" in the APIC table. From acpidump:
[02Ch 0044 1] Subtable Type : 00 [Processor Local APIC] [02Dh 0045 1] Length : 08 [02Eh 0046 1] Processor ID : 00 [02Fh 0047 1] Local Apic ID : 00 [030h 0048 4] Flags (decoded below) : 00000001 Processor Enabled : 1
[034h 0052 1] Subtable Type : 00 [Processor Local APIC] [035h 0053 1] Length : 08 [036h 0054 1] Processor ID : 01 [037h 0055 1] Local Apic ID : 01 [038h 0056 4] Flags (decoded below) : 00000001 Processor Enabled : 1
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