linux-kernel - Re: [RFC PATCH v3 00/17] x86/resctrl : Support AMD Assignable Bandwidth Monitoring Counters (ABMC)

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Date: Thu, 4 Apr 2024 12:08:43 -0700
From: Peter Newman <peternewman@...gle.com>
To: Babu Moger <babu.moger@....com>
Cc: corbet@....net, fenghua.yu@...el.com, reinette.chatre@...el.com, 
	tglx@...utronix.de, mingo@...hat.com, bp@...en8.de, 
	dave.hansen@...ux.intel.com, x86@...nel.org, hpa@...or.com, 
	paulmck@...nel.org, rdunlap@...radead.org, tj@...nel.org, 
	peterz@...radead.org, yanjiewtw@...il.com, kim.phillips@....com, 
	lukas.bulwahn@...il.com, seanjc@...gle.com, jmattson@...gle.com, 
	leitao@...ian.org, jpoimboe@...nel.org, rick.p.edgecombe@...el.com, 
	kirill.shutemov@...ux.intel.com, jithu.joseph@...el.com, kai.huang@...el.com, 
	kan.liang@...ux.intel.com, daniel.sneddon@...ux.intel.com, 
	pbonzini@...hat.com, sandipan.das@....com, ilpo.jarvinen@...ux.intel.com, 
	maciej.wieczor-retman@...el.com, linux-doc@...r.kernel.org, 
	linux-kernel@...r.kernel.org, eranian@...gle.com, james.morse@....com
Subject: Re: [RFC PATCH v3 00/17] x86/resctrl : Support AMD Assignable
 Bandwidth Monitoring Counters (ABMC)

Hi Babu,

On Thu, Mar 28, 2024 at 6:07 PM Babu Moger <babu.moger@....com> wrote:
>    The list follows the following format:
>
>        * Default CTRL_MON group:
>                "//<domain_id>=<assignment_flags>"
>
>        * Non-default CTRL_MON group:
>                "<CTRL_MON group>//<domain_id>=<assignment_flags>"
>
>        * Child MON group of default CTRL_MON group:
>                "/<MON group>/<domain_id>=<assignment_flags>"
>
>        * Child MON group of non-default CTRL_MON group:
>                "<CTRL_MON group>/<MON group>/<domain_id>=<assignment_flags>"
>
>        Assignment flags can be one of the following:
>
>         t  MBM total event is assigned
>         l  MBM local event is assigned
>         tl Both total and local MBM events are assigned
>         _  None of the MBM events are assigned
>
>         Examples:
>
>         # cat /sys/fs/resctrl/info/L3_MON/mbm_assign_control
>         non_defult_group//0=tl;1=tl;2=tl;3=tl;4=tl;5=tl;6=tl;7=tl;
>         non_defult_group/non_default_mon1/0=tl;1=tl;2=tl;3=tl;4=tl;5=tl;6=tl;7=tl;
>         //0=tl;1=tl;2=tl;3=tl;4=tl;5=tl;6=tl;7=tl;
>         /default_mon1/0=tl;1=tl;2=tl;3=tl;4=tl;5=tl;6=tl;7=tl;
>
>         There are four groups and all the groups have local and total event assigned.
>
>         "//" - This is a default CONTROL MON group
>
>         "non_defult_group//" - This is non default CONTROL MON group
>
>         "/default_mon1/"  - This is Child MON group of the defult group
>
>         "non_defult_group/non_default_mon1/" - This is child MON group of the non default group
>
>         =tl means both total and local events are assigned.

I recall there was supposed to be a way to perform the same update on
all domains together so that it isn't tedious to not do per-domain
customizations. (And also to avoid serializing programming all the
domains the same way.)


>
>  .../admin-guide/kernel-parameters.txt         |   2 +-
>  Documentation/arch/x86/resctrl.rst            | 144 ++++
>  arch/x86/include/asm/cpufeatures.h            |   1 +
>  arch/x86/include/asm/msr-index.h              |   2 +
>  arch/x86/kernel/cpu/cpuid-deps.c              |   3 +
>  arch/x86/kernel/cpu/resctrl/core.c            |  25 +-
>  arch/x86/kernel/cpu/resctrl/internal.h        |  56 +-
>  arch/x86/kernel/cpu/resctrl/monitor.c         |  24 +-
>  arch/x86/kernel/cpu/resctrl/rdtgroup.c        | 714 +++++++++++++++++-
>  arch/x86/kernel/cpu/scattered.c               |   1 +
>  include/linux/resctrl.h                       |  12 +
>  11 files changed, 964 insertions(+), 20 deletions(-)
>
> --
> 2.34.1
>

This should be fine for me to get started with. I'll see if I can work
backwards from the patches adding the parsing code to see how I'll
work the software implementation in.

Thanks!
-Peter