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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <a5029ad6-3e5e-46bf-881f-950a8a393956@intel.com>
Date: Tue, 23 Apr 2024 21:15:07 -0700
From: Reinette Chatre <reinette.chatre@...el.com>
To: Dave Martin <Dave.Martin@....com>, "Moger, Babu" <babu.moger@....com>
CC: Peter Newman <peternewman@...gle.com>, <corbet@....net>,
	<fenghua.yu@...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)



On 4/23/2024 5:37 AM, Dave Martin wrote:
> On Mon, Apr 22, 2024 at 03:44:26PM -0500, Moger, Babu wrote:
>> Hi Dave,
>>
>> On 4/22/24 11:34, Dave Martin wrote:
>>> Hi Babu,
>>>
>>> On Thu, Apr 04, 2024 at 03:02:45PM -0500, Moger, Babu wrote:
>>>> Hi Peter,
>>>>
>>>>
>>>> On 4/4/24 14:08, Peter Newman wrote:
>>>>> 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
>>>>
>>>> Yes. Correct. Reinette suggested to have "no domains" means ALL the domains.
>>>
>>> Would "*" be more intuitive?
>>
>> We could. But I don't see the need for wildcard ("*") or ranges and
>> complexity that comes with that.
> 
> For "*", I mean that this would just stand for "all cpus", not a generic
> string match; apologies if I didn't make that clear.

(reading this by replacing "all cpus" with "all domains")

This sounds reasonable to me. It may indeed make the parsing simpler by
not needing the ugly checks Babu mentioned in [1].

Reinette

[1] https://lore.kernel.org/lkml/7ccd59b8-9fe3-4d1f-82f5-f33d96dbf5ac@amd.com/