On Thu, Dec 7, 2023 at 11:56 AM Tony Luck <tony.luck@xxxxxxxxx> wrote: > > New mount option may be used to choose a specific memory bandwidth > monitoring event to feed the MBA Software Controller(mba_sc) feedback > loop. > > Signed-off-by: Tony Luck <tony.luck@xxxxxxxxx> > --- > Documentation/arch/x86/resctrl.rst | 16 ++++++++++++++-- > 1 file changed, 14 insertions(+), 2 deletions(-) > > diff --git a/Documentation/arch/x86/resctrl.rst b/Documentation/arch/x86/resctrl.rst > index a6279df64a9d..a0c521db6786 100644 > --- a/Documentation/arch/x86/resctrl.rst > +++ b/Documentation/arch/x86/resctrl.rst > @@ -35,7 +35,8 @@ about the feature from resctrl's info directory. > > To use the feature mount the file system:: > > - # mount -t resctrl resctrl [-o cdp[,cdpl2][,mba_MBps][,debug]] /sys/fs/resctrl > + # mount -t resctrl resctrl [-o cdp[,cdpl2][,mba_MBps] \ > + [,mba_MBps_event=[mbm_local_bytes|mbm_total_bytes]][,debug]] /sys/fs/resctrl > > mount options are: > > @@ -45,7 +46,12 @@ mount options are: > Enable code/data prioritization in L2 cache allocations. > "mba_MBps": > Enable the MBA Software Controller(mba_sc) to specify MBA > - bandwidth in MBps > + bandwidth in MBps. Defaults to using MBM local bandwidth, > + but will use total bandwidth on systems that do not support > + local bandwidth monitoring. > +"mba_MBps_event=[mbm_local_bytes|mbm_total_bytes]": > + Enable the MBA Software Controller(mba_sc) with a specific > + MBM event as input to the feedback loop. > "debug": > Make debug files accessible. Available debug files are annotated with > "Available only with debug option". > @@ -538,6 +544,12 @@ where as user can switch to the "MBA software controller" mode using > a mount option 'mba_MBps'. The schemata format is specified in the below > sections. > > +By default the software feedback mechanism uses measurement of local > +memory bandwidth to make adjustments to throttling levels. If a system > +is running applications with poor NUMA locality users may want to use > +the "mba_MBps_event=mbm_total_bytes" mount option which will use total > +memory bandwidth measurements instead of local. > + > L3 schemata file details (code and data prioritization disabled) > ---------------------------------------------------------------- > With CDP disabled the L3 schemata format is:: > -- > 2.41.0 > for content: Reviewed-by: Peter Newman <peternewman@xxxxxxxxxx>
