Re: [PATCH v9 14/31] x86,fs/resctrl: Support binary fixed point event counters

[Reinette Chatre <reinette.chatre@intel.com>]

Hi Tony,

On 8/29/25 12:33 PM, Tony Luck wrote:
> resctrl assumes that all monitor events can be displayed as unsigned
> decimal integers.
> 
> Hardware architecture counters may provide some telemetry events with
> greater precision where the event is not a simple count, but is a
> measurement of some sort (e.g. Joules for energy consumed).
> 
> Add a new argument to resctrl_enable_mon_event() for architecture code
> to inform the file system that the value for a counter is a fixed-point
> value with a specific number of binary places.
> Only allow architecture to use floating point format on events that the
> file system has marked with mon_evt::is_floating_point.
> 
> Display fixed point values with values rounded to an appropriate number
> of decimal places for the precision of the number of binary places
> provided. Add one extra decimal place for every three additional binary
> places, except for low precision binary values where exact representation
> is possible:
> 
>   1 binary place is 0.0 or 0.5.			=> 1 decimal place

nit: "0.5." -> "0.5"

>   2 binary places is 0.0, 0.25, 0.5, 0.75	=> 2 decimal places
>   3 binary places is 0.0, 0.125, etc.		=> 3 decimal places
> 
> Signed-off-by: Tony Luck <tony.luck@intel.com>
> ---

| Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>

Reinette