x2APIC support (Re: How many CPU cores does FreeBSD support?)

Wed, 04 Jan 2017 11:59:10 -0800 

Hi
I think your issue relates to x2APIC support and I don't think that full support for parsing x2APIC MADT entries and doing interrupts remapping has been committed yet from my very brief search of the source and commit messages. I've copied Andriy Gapon and Konstantin Belousov who participated in another x2APIC thread in September last year. They will probably have a more intelligible response. 

sys/x86/include/apicvar.h limits APIC IDs as follows:

#define MAX_APIC_ID     0xfe
#define APIC_ID_ALL     0xff


This is why CPUs with an APIC ID above 255 are being ignored in 
acpica/madt.c


sys/x86/x86/mptable.c has this choice piece of code:

        if (intr->dst_apic_id == 0xff)
                apic_id = APIC_ID_ALL;
        else
                apic_id = intr->dst_apic_id;

which for the current value of APIC_ID_ALL can simply be rewritten as:

        apic_id = intr->dst_apic_id;

I do not think it is safe to increase MAX_APIC_ID yet.

Ian

--
Ian Freislich

On 01/04/17 13:53, 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
     r...@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 @ 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?

- Eric

On Tue, Jan 3, 2017 at 11:41 PM Shane Ambler <free...@shaneware.biz> wrote:


On 04/01/2017 08:08, Eric Joyner wrote:

I have an 11.0-RELEASE-p1 system with:

hw.model: Intel(R) Xeon Phi(TM) CPU 7250 @ 1.40GHz

It's got 68 cores, but with 4-way SMT, I think it should show up with 272
logical cores on FreeBSD.

However, in both kern.sched.topology_spec and hw.ncpu, it shows there are
only 223 cores.

Is the limit effectively 223 cores, even though I see some #define MAXCPU
256 lines in the source?

You will probably find freebsd-current a better mailing list for this.

How many show in dmesg?

  From https://svnweb.freebsd.org/base?view=revision&revision=270223
Bump MAXCPU on amd64 from 64 to 256.  In practice APIC only permits 255
CPUs (IDs 0 through 254).  Getting above that limit requires x2APIC.

Also note that changing MAXCPU breaks ABI compatability so you will
need to recompile.
https://svnweb.freebsd.org/base?view=revision&revision=284720

--
FreeBSD - the place to B...Software Developing

Shane Ambler



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