On Wed, Jul 23, 2025 at 05:47:21PM +1000, David Gwynne wrote:
> i sent an old version of this around a year or two ago, which devolved
> into a discussion around how annoying the repeated cpu info is in dmesg.
> that's since been addressed, so i'm trying this out again.
> 
> if an intel cpu provides information about the type of cpu, this adds it
> to the topology line in dmesg output. this is particularly interesting
> on hybrid systems.

That's what this looks like on my x1 nano2. I think it looks nice and it
would be helpful for ignorami like me: a year ago I found it quite
tedious to stare at the dmesg to figure out which cores are the P and
which ones the E cores on this machine.

cpu0 at mainbus0: apid 0 (boot processor)
cpu0: 12th Gen Intel(R) Core(TM) i7-1260P, 1995.55 MHz, 06-9a-03, patch 00000437
cpu0: cpuid 1 edx=bfebfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CFLUSH,DS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE> ecx=77fafbff<SSE3,PCLMUL,DTES64,MWAIT,DS-CPL,VMX,SMX,EST,TM2,SSSE3,SDBG,FMA3,CX16,xTPR,PDCM,PCID,SSE4.1,SSE4.2,x2APIC,MOVBE,POPCNT,DEADLINE,AES,XSAVE,AVX,F16C,RDRAND>
cpu0: cpuid 6 eax=df8ff7<SENSOR,ARAT,PTS> ecx=409<EFFFREQ>
cpu0: cpuid 7.0 ebx=239c27eb<FSGSBASE,TSC_ADJUST,BMI1,AVX2,SMEP,BMI2,ERMS,INVPCID,RDSEED,ADX,SMAP,CLFLUSHOPT,CLWB,PT,SHA> ecx=984007ac<UMIP,PKU,WAITPKG,PKS> edx=fc18c410<MD_CLEAR,IBT,IBRS,IBPB,STIBP,L1DF,SSBD>
cpu0: cpuid a vers=5, gp=6, gpwidth=48, ff=3, ffwidth=48
cpu0: cpuid d.1 eax=f<XSAVEOPT,XSAVEC,XGETBV1,XSAVES>
cpu0: cpuid 80000001 edx=2c100800<NXE,PAGE1GB,RDTSCP,LONG> ecx=121<LAHF,ABM,3DNOWP>
cpu0: cpuid 80000007 edx=100<ITSC>
cpu0: msr 10a=14c8fd6b<IBRS_ALL,SKIP_L1DFL,MDS_NO,IF_PSCHANGE,TAA_NO,MISC_PKG_CT,ENERGY_FILT,DOITM,SBDR_SSDP_N,FBSDP_NO,PSDP_NO,RRSBA,OVERCLOCK,GDS_NO,RFDS_CLEAR>
cpu0: 48KB 64b/line 12-way D-cache, 32KB 64b/line 8-way I-cache, 1MB 64b/line 10-way L2 cache, 18MB 64b/line 12-way L3 cache
cpu0: smt 0, core 0, package 0, performance core
mtrr: Pentium Pro MTRR support, 10 var ranges, 88 fixed ranges
cpu0: apic clock running at 38MHz
cpu0: mwait min=64, max=64, C-substates=0.2.0.2.0.1.0.1, IBE
cpu1 at mainbus0: apid 8 (application processor)
cpu1: 12th Gen Intel(R) Core(TM) i7-1260P, 1995.58 MHz, 06-9a-03, patch 00000437
cpu1: smt 0, core 4, package 0, performance core
cpu2 at mainbus0: apid 16 (application processor)
cpu2: 12th Gen Intel(R) Core(TM) i7-1260P, 1995.57 MHz, 06-9a-03, patch 00000437
cpu2: smt 0, core 8, package 0, performance core
cpu3 at mainbus0: apid 24 (application processor)
cpu3: 12th Gen Intel(R) Core(TM) i7-1260P, 1995.58 MHz, 06-9a-03, patch 00000437
cpu3: smt 0, core 12, package 0, performance core
cpu4 at mainbus0: apid 32 (application processor)
cpu4: 12th Gen Intel(R) Core(TM) i7-1260P, 1995.41 MHz, 06-9a-03, patch 00000437
cpu4: 32KB 64b/line 8-way D-cache, 64KB 64b/line 8-way I-cache, 2MB 64b/line 16-way L2 cache, 18MB 64b/line 12-way L3 cache
cpu4: smt 0, core 16, package 0, efficiency core
cpu5 at mainbus0: apid 34 (application processor)
cpu5: 12th Gen Intel(R) Core(TM) i7-1260P, 1995.40 MHz, 06-9a-03, patch 00000437
cpu5: smt 0, core 17, package 0, efficiency core
cpu6 at mainbus0: apid 36 (application processor)
cpu6: 12th Gen Intel(R) Core(TM) i7-1260P, 1995.40 MHz, 06-9a-03, patch 00000437
cpu6: smt 0, core 18, package 0, efficiency core
cpu7 at mainbus0: apid 38 (application processor)
cpu7: 12th Gen Intel(R) Core(TM) i7-1260P, 1995.40 MHz, 06-9a-03, patch 00000437
cpu7: smt 0, core 19, package 0, efficiency core
cpu8 at mainbus0: apid 40 (application processor)
cpu8: 12th Gen Intel(R) Core(TM) i7-1260P, 1995.41 MHz, 06-9a-03, patch 00000437
cpu8: smt 0, core 20, package 0, efficiency core
cpu9 at mainbus0: apid 42 (application processor)
cpu9: 12th Gen Intel(R) Core(TM) i7-1260P, 1995.40 MHz, 06-9a-03, patch 00000437
cpu9: smt 0, core 21, package 0, efficiency core
cpu10 at mainbus0: apid 44 (application processor)
cpu10: 12th Gen Intel(R) Core(TM) i7-1260P, 1995.40 MHz, 06-9a-03, patch 00000437
cpu10: smt 0, core 22, package 0, efficiency core
cpu11 at mainbus0: apid 46 (application processor)
cpu11: 12th Gen Intel(R) Core(TM) i7-1260P, 1995.40 MHz, 06-9a-03, patch 00000437
cpu11: smt 0, core 23, package 0, efficiency core