linux-kernel - Re: [PATCH v8 07/25] x86/resctrl: Introduce the interface to display monitor mode

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Message-ID: <4da658fa-3cea-4388-86f4-d4b0fb5f0903@amd.com>
Date: Thu, 10 Oct 2024 09:54:47 -0500
From: "Moger, Babu" <babu.moger@....com>
To: Tony Luck <tony.luck@...el.com>
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Subject: Re: [PATCH v8 07/25] x86/resctrl: Introduce the interface to display
 monitor mode

Hi Tony,

Thanks for reviewing the patches.

On 10/9/24 17:42, Tony Luck wrote:
> On Wed, Oct 09, 2024 at 12:39:32PM -0500, Babu Moger wrote:
>> +"mbm_assign_mode":
>> +	Reports the list of monitoring modes supported. The enclosed brackets
>> +	indicate which mode is enabled.
>> +	::
>> +
>> +	  cat /sys/fs/resctrl/info/L3_MON/mbm_assign_mode
>> +	  [mbm_cntr_assign]
>> +	  default
>> +
>> +	"mbm_cntr_assign":
>> +
>> +	In mbm_cntr_assign mode user-space is able to specify which control
>> +	or monitor groups in resctrl should have a counter assigned using the
>> +	'mbm_assign_control' file. The number of counters available is described
>> +	in the 'num_mbm_cntrs' file. Changing the mode may cause all counters on
>> +	a resource to reset.
>> +
>> +	The mode is useful on platforms which support more control and monitor
>> +	groups than hardware counters, meaning 'unassigned' control or monitor
>> +	groups will report 'Unavailable' or count the traffic in an unpredictable
>> +	way.
>> +
>> +	AMD Platforms with ABMC (Assignable Bandwidth Monitoring Counters) feature
>> +	enable this mode by default so that counters remain assigned even when the
>> +	corresponding RMID is not in use by any processor.
>> +
>> +	"default":
>> +
>> +	By default resctrl assumes each control and monitor group has a hardware
>> +	counter. Hardware that does not support 'mbm_cntr_assign' mode will still
>> +	allow more control or monitor groups than 'num_rmids' to be created. In
> 
> Should that be s/num_rmids/num_mbm_cntrs/ ?

It is actually num_rmids here as in default mode, num_rmid_cntrs are not
available.
-- 
Thanks
Babu Moger