cpu/resctrl/monitor.c

427  * Supporting function to calculate the memory bandwidth
428  * and delta bandwidth in MBps. The chunks value previously read by
491  * adjust the bandwidth percentage values via the IA32_MBA_THRTL_MSRs so
494  *   current bandwidth(cur_bw) < user specified bandwidth(user_bw)
496  * This uses the MBM counters to measure the bandwidth and MBA throttle
497  * MSRs to control the bandwidth for a particular rdtgrp. It builds on the
501  * timer. Having 1s interval makes the calculation of bandwidth simpler.
503  * Although MBA's goal is to restrict the bandwidth to a maximum, there may
504  * be a need to increase the bandwidth to avoid unnecessarily restricting
507  * Since MBA controls the L2 external bandwidth where as MBM measures the
508  * L3 external bandwidth the following sequence could lead to such a
512  * phases -> mba_sc kicks in and reduced bandwidth percentage values -> but
517  * unnecessarily restricting such rdtgroups, we also increase the bandwidth.
562 	 * Scale up/down the bandwidth linearly for the ctrl group.  The  in update_mba_bw()
563 	 * bandwidth step is the bandwidth granularity specified by the  in update_mba_bw()
566 	 * The delta_bw is used when increasing the bandwidth so that we  in update_mba_bw()
571 	 * bandwidth step is 20MBps(> user_bw - cur_bw), we would keep  in update_mba_bw()
590 	 * This is because (1)the increase in bandwidth is not perfectly  in update_mba_bw()
763  * because as per the SDM the total and local memory bandwidth