Re: How many CPU cores does FreeBSD support?

On Wed, Jan 04, 2017 at 06:53:23PM +0000, Eric Joyner wrote:
> Adding freebsd-current, because that's a good idea.
> 
> I see these lines in the beginning of dmesg:
> 
> MADT: Ignoring local APIC ID 256 (too high)
> 
> 
>       [907/911]
> MADT: Ignoring local APIC ID 260 (too high)
> 
> 
>       [906/911]
> MADT: Ignoring local APIC ID 264 (too high)
> 
> 
>       [905/911]
> MADT: Ignoring local APIC ID 268 (too high)
> 
> 
>       [904/911]
> MADT: Ignoring local APIC ID 272 (too high)
> 
> 
>       [903/911]
> MADT: Ignoring local APIC ID 276 (too high)
> 
> 
>       [902/911]
> MADT: Ignoring local APIC ID 280 (too high)
> 
> 
>       [901/911]
> MADT: Ignoring local APIC ID 272 (too high)
> 
> 
>       [903/911]
> MADT: Ignoring local APIC ID 276 (too high)
> 
> 
>       [902/911]
> MADT: Ignoring local APIC ID 280 (too high)
> 
> 
>       [901/911]
> MADT: Ignoring local APIC ID 276 (too high)
> 
> 
>       [902/911]
> MADT: Ignoring local APIC ID 280 (too high)
> MADT: Ignoring local APIC ID 284 (too high)
> MADT: Ignoring local APIC ID 288 (too high)
> MADT: Ignoring local APIC ID 292 (too high)
> MADT: Ignoring local APIC ID 296 (too high)
> MADT: Ignoring local APIC ID 300 (too high)
> MADT: Ignoring local APIC ID 257 (too high)
> MADT: Ignoring local APIC ID 261 (too high)
> MADT: Ignoring local APIC ID 265 (too high)
> MADT: Ignoring local APIC ID 269 (too high)
> MADT: Ignoring local APIC ID 273 (too high)
> MADT: Ignoring local APIC ID 277 (too high)
> MADT: Ignoring local APIC ID 281 (too high)
> MADT: Ignoring local APIC ID 285 (too high)
> MADT: Ignoring local APIC ID 289 (too high)
> MADT: Ignoring local APIC ID 293 (too high)
> MADT: Ignoring local APIC ID 297 (too high)
> MADT: Ignoring local APIC ID 301 (too high)
> MADT: Ignoring local APIC ID 258 (too high)
> MADT: Ignoring local APIC ID 262 (too high)
> MADT: Ignoring local APIC ID 266 (too high)
> MADT: Ignoring local APIC ID 270 (too high)
> MADT: Ignoring local APIC ID 274 (too high)
> MADT: Ignoring local APIC ID 278 (too high)
> MADT: Ignoring local APIC ID 282 (too high)
> MADT: Ignoring local APIC ID 286 (too high)
> MADT: Ignoring local APIC ID 290 (too high)
> MADT: Ignoring local APIC ID 294 (too high)
> MADT: Ignoring local APIC ID 298 (too high)
> MADT: Ignoring local APIC ID 302 (too high)
> MADT: Ignoring local APIC ID 255 (too high)
> MADT: Ignoring local APIC ID 259 (too high)
> MADT: Ignoring local APIC ID 263 (too high)
> MADT: Ignoring local APIC ID 267 (too high)
> MADT: Ignoring local APIC ID 271 (too high)
> MADT: Ignoring local APIC ID 275 (too high)
> MADT: Ignoring local APIC ID 279 (too high)
> MADT: Ignoring local APIC ID 283 (too high)
> MADT: Ignoring local APIC ID 287 (too high)
> MADT: Ignoring local APIC ID 291 (too high)
> MADT: Ignoring local APIC ID 295 (too high)
> MADT: Ignoring local APIC ID 299 (too high)
> MADT: Ignoring local APIC ID 303 (too high)
> Copyright (c) 1992-2016 The FreeBSD Project.
> Copyright (c) 1979, 1980, 1983, 1986, 1988, 1989, 1991, 1992, 1993, 1994
>         The Regents of the University of California. All rights reserved.
> FreeBSD is a registered trademark of The FreeBSD Foundation.
> FreeBSD 11.0-RELEASE-p1 #0 r306420: Thu Sep 29 01:43:23 UTC 2016
>     root_at_releng2.nyi.freebsd.org:/usr/obj/usr/src/sys/GENERIC amd64
> FreeBSD clang version 3.8.0 (tags/RELEASE_380/final 262564) (based on LLVM
> 3.8.0)
> SRAT: No CPU found for memory domain 1
> VT(efifb): resolution 800x600
> CPU: Intel(R) Xeon Phi(TM) CPU 7250 _at_ 1.40GHz (1396.80-MHz K8-class CPU)
>   Origin="GenuineIntel"  Id=0x50671  Family=0x6  Model=0x57  Stepping=1
> 
> Features=0xbfebfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CLFLUSH,DTS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE>
> 
> Features2=0x7ff8f39f<SSE3,PCLMULQDQ,DTES64,MON,DS_CPL,EST,TM2,SSSE3,FMA,CX16,xTPR,PDCM,SSE4.1,SSE4.2,x2APIC,MOVBE,POPCNT,TSCDLT,AESNI,XSAVE,OSXSAVE,AVX,F16C,RDRAND>
>   AMD Features=0x2c100800<SYSCALL,NX,Page1GB,RDTSCP,LM>
>   AMD Features2=0x121<LAHF,ABM,Prefetch>
>   Structured Extended
> Features=0x1c0d23ab<FSGSBASE,TSCADJ,BMI1,AVX2,SMEP,BMI2,ERMS,NFPUSG,AVX512F,RDSEED,ADX,AVX512PF,AVX512ER,AVX512CD>
>   Structured Extended Features2=0x1<PREFETCHWT1>
>   XSAVE Features=0x1<XSAVEOPT>
>   TSC: P-state invariant, performance statistics
> real memory  = 223332007936 (212986 MB)
> avail memory = 216976429056 (206924 MB)
> Event timer "LAPIC" quality 600
> ACPI APIC Table: <INTEL  S7200AP>
> FreeBSD/SMP: Multiprocessor System Detected: 223 CPUs
> FreeBSD/SMP: Non-uniform topology
> 
> It sounds like those MADT errors point to the problem?

In sys/x86/acpica/madt.c file, function madt_add_cpu(), just remove
the block
	if (apic_id > MAX_APIC_ID) {
		printf("MADT: Ignoring local APIC ID %u (too high)\n",
		    apic_id);
		return;
	}
Best to do it on HEAD and not on 11.0.
If it helps, commit the change.

Also, for >= 256 CPUs, you might need to enable interrupt remapping
in the DMAR, use loader tunables
	hw.dmar.enable <= to enable DMAR
	hw.dmar.ir <= to enable remapping
	hw.dmar.dma <= to disable IOMMU if it interacts badly with your hw