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Subject: Re: [PATCH 0/1] sched/topology: NUMA distance deduplication
To:     Valentin Schneider <valentin.schneider@arm.com>
Cc:     "Peter Zijlstra (Intel)" <peterz@infradead.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        "linux-ia64@vger.kernel.org" <linux-ia64@vger.kernel.org>,
        Sergei Trofimovich <slyfox@gentoo.org>,
        debian-ia64 <debian-ia64@lists.debian.org>
References: <255d6b5d-194e-eb0e-ecdd-97477a534441@physik.fu-berlin.de>
 <8735wtr2ro.mognet@arm.com>
From:   John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Message-ID: <cf4d7277-54a0-8bc7-60fb-9b2f6befb511@physik.fu-berlin.de>
Date:   Wed, 17 Mar 2021 20:47:36 +0100
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Helo Valentin!

On 3/17/21 8:36 PM, Valentin Schneider wrote:
> I see ACPI in your boot logs, so I'm guessing you have a bogus SLIT table
> (the ACPI table with node distances). You should be able to double check
> this with something like:
> 
> $ acpidump > acpi.dump
> $ acpixtract -a acpi.dump
> $ iasl -d *.dat
> $ cat slit.dsl

There does not seem to be a SLIT table in my firmware:

root@glendronach:~# acpidump > acpi.dump
root@glendronach:~# acpixtract -a acpi.dump

Intel ACPI Component Architecture
ACPI Binary Table Extraction Utility version 20200925
Copyright (c) 2000 - 2020 Intel Corporation

acpixtract(31194): unaligned access to 0x60000fffff9b3925, ip=0x4000000000003e91
  SSDT -    3768 bytes written (0x00000EB8) - ssdt1.dat
acpixtract(31194): unaligned access to 0x60000fffff9b3925, ip=0x4000000000003e00
acpixtract(31194): unaligned access to 0x60000fffff9b3925, ip=0x4000000000003e91
  SPCR -      80 bytes written (0x00000050) - spcr.dat
acpixtract(31194): unaligned access to 0x60000fffff9b3925, ip=0x4000000000003e00
acpixtract(31194): unaligned access to 0x60000fffff9b3925, ip=0x4000000000003e91
  APIC -     200 bytes written (0x000000C8) - apic.dat
  SSDT -    1110 bytes written (0x00000456) - ssdt2.dat
  SSDT -     316 bytes written (0x0000013C) - ssdt3.dat
  SPMI -      80 bytes written (0x00000050) - spmi.dat
  DSDT -   58726 bytes written (0x0000E566) - dsdt.dat
  SSDT -     312 bytes written (0x00000138) - ssdt4.dat
  SSDT -    2150 bytes written (0x00000866) - ssdt5.dat
  SSDT -     316 bytes written (0x0000013C) - ssdt6.dat
  SSDT -    3768 bytes written (0x00000EB8) - ssdt7.dat
  FACP -     244 bytes written (0x000000F4) - facp.dat
  SSDT -    1203 bytes written (0x000004B3) - ssdt8.dat
  CPEP -      52 bytes written (0x00000034) - cpep.dat
  SSDT -     316 bytes written (0x0000013C) - ssdt9.dat
  DBGP -      52 bytes written (0x00000034) - dbgp.dat
  SSDT -    3768 bytes written (0x00000EB8) - ssdt10.dat
  FACS -      64 bytes written (0x00000040) - facs.dat
root@glendronach:~#

root@glendronach:~# ls *.dsl *.dat
apic.dat  cpep.dsl  dsdt.dat  facp.dsl  spcr.dat  spmi.dsl    ssdt1.dat  ssdt2.dsl  ssdt4.dat  ssdt5.dsl  ssdt7.dat  ssdt8.dsl
apic.dsl  dbgp.dat  dsdt.dsl  facs.dat  spcr.dsl  ssdt10.dat  ssdt1.dsl  ssdt3.dat  ssdt4.dsl  ssdt6.dat  ssdt7.dsl  ssdt9.dat
cpep.dat  dbgp.dsl  facp.dat  facs.dsl  spmi.dat  ssdt10.dsl  ssdt2.dat  ssdt3.dsl  ssdt5.dat  ssdt6.dsl  ssdt8.dat  ssdt9.dsl
root@glendronach:~#

> a) Complain to your hardware vendor to have them fix the table and ship a
>    firmware fix

The hardware is probably too old for the vendor to care about fixing it.

> b) Fix the ACPI table yourself - I've been told it's doable for *some* of
>    them, but I've never done that myself
> c) Compile your kernel with CONFIG_NUMA=n, as AFAICT you only actually have
>    a single node
> d) Ignore the warning
> 
> 
> c) is clearly not ideal if you want to use a somewhat generic kernel image
> on a wide host of machines; d) is also a bit yucky...

Shouldn't the kernel be able to cope with quirky hardware? From what I remember in the past,
ACPI tables used to be broken quite a lot and the kernel contained workarounds for such cases,
didn't it?

Adrian

-- 
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer - glaubitz@debian.org
`. `'   Freie Universitaet Berlin - glaubitz@physik.fu-berlin.de
  `-    GPG: 62FF 8A75 84E0 2956 9546  0006 7426 3B37 F5B5 F913