Hi Babu, On 10/9/24 10:39 AM, Babu Moger wrote: > > This series adds the support for Assignable Bandwidth Monitoring Counters > (ABMC). It is also called QoS RMID Pinning feature > > Series is written such that it is easier to support other assignable > features supported from different vendors. > > The feature details are documented in the APM listed below [1]. > [1] AMD64 Architecture Programmer's Manual Volume 2: System Programming > Publication # 24593 Revision 3.41 section 19.3.3.3 Assignable Bandwidth > Monitoring (ABMC). The documentation is available at > Link: https://bugzilla.kernel.org/show_bug.cgi?id=206537 > > The patches are based on top of commit > 5b0c5f05fb2fe (tip/master) Merge branch into tip/master: 'x86/splitlock' > > # Introduction > > Users can create as many monitor groups as RMIDs supported by the hardware. > However, bandwidth monitoring feature on AMD system only guarantees that > RMIDs currently assigned to a processor will be tracked by hardware. > The counters of any other RMIDs which are no longer being tracked will be > reset to zero. The MBM event counters return "Unavailable" for the RMIDs > that are not tracked by hardware. So, there can be only limited number of > groups that can give guaranteed monitoring numbers. With ever changing > configurations there is no way to definitely know which of these groups > are being tracked for certain point of time. Users do not have the option > to monitor a group or set of groups for certain period of time without > worrying about RMID being reset in between. "worrying about RMID being reset in between" -> "worrying about counter being reset in between"? > > The ABMC feature provides an option to the user to assign a hardware > counter to an RMID, event pair and monitor the bandwidth as long as it is > assigned. The assigned RMID will be tracked by the hardware until the user > unassigns it manually. There is no need to worry about counters being reset > during this period. Additionally, the user can specify a bitmask identifying > the specific bandwidth types from the given source to track with the counter. > > Without ABMC enabled, monitoring will work in current 'default' mode without > assignment option. > Reinette
