Re: [PATCH v4 2/3] arm_mpam: resctrl: Add pass-through resctrl_arch_preconvert_bw()

[Reinette Chatre]

Hi Ben,

On 7/6/26 9:06 AM, Ben Horgan wrote:
> resctrl rounds up the percentage value of the MBA based on the bw_gran. As
> MPAM uses a binary fixed point fraction format for MBA rather than a
> decimal percentage, this introduces rounding errors.
> 
> Without this additional rounding, if the user reads the value in an MB
> schema and then writes it back to the schema, the value in hardware won't
> change. However, with this additional rounding, this guarantee is broken
> for systems with mbw_wd < 7.
> 
> resctrl is introducing resctrl_arch_preconvert_bw() to allow the arch code
> to specify the conversion resctrl does to the user-provided bandwidth
> value. Add the MPAM version of resctrl_arch_preconvert_bw(). This does no
> conversion.
> 
> Signed-off-by: Ben Horgan <ben.horgan@xxxxxxx>
> Reviewed-by: Reinette Chatre <reinette.chatre@xxxxxxxxx>
> 

Unfortunately the "---" separator is missing here.

> Changes since v3:
> Parameter order switch (Reinette)
> Add Reinette's R-b
> ---
Reinette