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Message-ID: <4413cec1-bbc6-9c88-dfdf-9790949a379e@amd.com>
Date: Tue, 5 Mar 2024 08:58:10 -0600
From: "Moger, Babu" <bmoger@....com>
To: Reinette Chatre <reinette.chatre@...el.com>, babu.moger@....com,
James Morse <james.morse@....com>, corbet@....net, fenghua.yu@...el.com,
tglx@...utronix.de, mingo@...hat.com, bp@...en8.de,
dave.hansen@...ux.intel.com, Peter Newman <peternewman@...gle.com>
Cc: 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
Subject: Re: [PATCH v2 00/17] x86/resctrl : Support AMD Assignable Bandwidth
Monitoring Counters (ABMC)
Hi Peter,
I want to get your feedback on this approach before I start working on
it. Please look at few examples below.
Thanks
Babu
On 3/4/2024 4:24 PM, Moger, Babu wrote:
> Hi Reinette,
>
> On 3/4/2024 1:58 PM, Reinette Chatre wrote:
>> Hi Babu,
>>
>> On 3/4/2024 11:34 AM, Moger, Babu wrote:
>>> On 3/1/2024 5:20 PM, Reinette Chatre wrote:
>>>> On 3/1/2024 12:36 PM, Moger, Babu wrote:
>>>>> On 2/29/24 15:50, Reinette Chatre wrote:
>>>>>> On 2/29/2024 12:37 PM, Moger, Babu wrote:
>>>>> To assign a counters to default group on domain 0.
>>>>> $echo "//00=+lt;01=+lt" >
>>>>> /sys/fs/resctrl/info/L3_MON/mbm_assign_control
>>>> It should not be necessary to use both "=" and "+" in the same
>>>> assignment.
>>>> I think of "=" as "assign" and "+" as append ("-" as remove).
>>> Here are our options.
>>>
>>> a. assign one event (+)
>> I prefer that we use consistent interface with what users may be used to
>> in other kernel interfaces, like dynamic debug.
>> Considering that, "+" will not be "assign one event" but instead
>> (let me copy text from dynamic debug to help):
>> "+ add the given flags"
>>
>> So + will add (append) the provided flags to the matching domain, it
>> can be multiple flags and does not impact existing flags.
>
> ok. Sure.
>
>
>>
>>> b. unassign one event (-)
>> "- remove the given flags" - it can be multiple flags that should be
>> removed from domain.
>>
>>> c. assign both (++ may be?)
>> No. Please do not constrain the interface with what needs to be
>> supported
>> for ABMC. We may want to add other flags in the future, do not limit
>> it to
>> two flags.
> ok Sure.
>>
>>> d. unassign both (_)
>> "=_" will unassign all flags without consideration of which flags
>> are set. User can also use "-l" to just unassign local MBM, "-t" to
>> unassign total MBM, or "-lt" to unassign local and total MBM
>> specifically.
>
> oh ok. got it.
>
>
>>
>>> I think append ( "=") is not required while assigning. It is
>>> confusing.
>> "=" is not append. It is assign:
>>
>> " = set the flags to the given flags"
> ok.
>>
>>> Assign or Add both involve same action.
>>>
>>> How about this? This might be easy to parse. May be space (" ")
>>> after the domain id.
>> Why a space?
>>
>>> <group>/<domain id> <action><event>; <domain id> <action><event>
>>>
>> <control group>/<monitor group/<domain id><action><flags or
>> _>;<domain id><action><flags or _>
>
>
> Based on our discussion, I am listing few examples here. Let me know
> if I missed something.
>
> mount -t resctrl resctrl /sys/fs/resctrl/
>
> 1. Assign both local and total counters to default group on domain 0
> and 1.
> $echo "//00=lt;01=lt" > /sys/fs/resctrl/info/L3_MON/mbm_assign_control
>
> $cat /sys/fs/resctrl/info/L3_MON/mbm_assign_control
> //00=lt;01=lt
>
> 2. Assign a total event to mon group inside the default group for both
> domain 0 and 1.
>
> $mkdir /sys/fs/resctrl/mon_groups/mon_a
> $echo "/mon_a/00+t;01+t" >
> /sys/fs/resctrl/info/L3_MON/mbm_assign_control
>
> $cat /sys/fs/resctrl/info/L3_MON/mbm_assign_control
> //00=lt;01=lt
> /mon_a/00=t;01=t
>
> 3. Assign a local event to non-default control mon group both domain 0
> and 1.
> $mkdir /sys/fs/resctrl/ctrl_a
> $echo "/ctrl_a/00=l;01=l" >
> /sys/fs/resctrl/info/L3_MON/mbm_assign_control
>
> $cat /sys/fs/resctrl/info/L3_MON/mbm_assign_control
> //00=lt;01=lt
> /mon_a/00=t;01=t
> /ctrl_a/00=l;01=l
>
> 4. Assign a both counters to mon group inside another control
> group(non-default).
> $mkdir /sys/fs/resctrl/ctrl_a/mon_ab/
> $echo "ctrl_a/mon_ab/00=lt;01=lt" >
> /sys/fs/resctrl/nfo/L3_MON/mbm_assign_contro
>
> $cat /sys/fs/resctrl/info/L3_MON/mbm_assign_control
> //00=lt;01=lt
> /mon_a/00=t;01=t
> /ctrl_a/00=l;01=l
> ctrl_a/mon_ab/00=lt;01=lt
>
> 5. Unassign a counter to mon group inside another control
> group(non-default).
> $echo "ctrl_a/mon_ab/00-l;01-l" >
> /sys/fs/resctrl/nfo/L3_MON/mbm_assign_control
>
> $cat /sys/fs/resctrl/info/L3_MON/mbm_assign_control
> //00=lt;01=lt
> /mon_a/00=t;01=t
> /ctrl_a/00=l;01=l
> ctrl_a/mon_ab/00=t;01=t
>
> 6. Unassign all the counters on a specific group.
> $echo "ctrl_a/mon_ab/00=_" >
> /sys/fs/resctrl/nfo/L3_MON/mbm_assign_control
>
> $cat /sys/fs/resctrl/info/L3_MON/mbm_assign_control
> //00=lt;01=lt
> /mon_a/00=t;01=t
> /ctrl_a/00=l;01=l
> ctrl_a/mon_ab/00=_;01=_
>
> Thanks
> Babu Moger
>
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