Hi Babu, On 3/28/2024 6:06 PM, Babu Moger wrote: > With the support of ABMC (Assignable Bandwidth Monitoring Counters) > feature, the user has the option to assign or unassign the RMID to > hardware counter and monitor the bandwidth for the longer duration. What is meant with "the longer duration" (this term is used throughout this series)? Perhaps "for as long as a hardware counter is assigned"? > > Provide the interface to assign the counter to the group. > > The ABMC feature implements a pair of MSRs, L3_QOS_ABMC_CFG (MSR > C000_03FDh) and L3_QOS_ABMC_DSC (MSR C000_3FEh). Each logical processor > implements a separate copy of these registers. Attempts to read or write > these MSRs when ABMC is not enabled will result in a #GP(0) exception. > > Individual assignable bandwidth counters are configured by writing to > L3_QOS_ABMC_CFG MSR and specifying the Counter ID, Bandwidth Source, and > Bandwidth Types. Reading L3_QOS_ABMC_DSC returns the configuration of the > counter specified by L3_QOS_ABMC_CFG [CtrID]. This mentions the AMD architecture parts needing configuration but not what resctrl parts are used to accomplish this configuration. It is difficult to understand this work without this connection. > > 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). > > Signed-off-by: Babu Moger <babu.moger@xxxxxxx> > Link: https://bugzilla.kernel.org/show_bug.cgi?id=206537 > --- > v3: Removed the static from the prototype of rdtgroup_assign_abmc. > The function is not called directly from user anymore. These > changes are related to global assignment interface. > > v2: Minor text changes in commit message. > --- > arch/x86/kernel/cpu/resctrl/internal.h | 1 + > arch/x86/kernel/cpu/resctrl/rdtgroup.c | 86 ++++++++++++++++++++++++++ > 2 files changed, 87 insertions(+) > > diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h > index 88453c86474b..9d84c80104f9 100644 > --- a/arch/x86/kernel/cpu/resctrl/internal.h > +++ b/arch/x86/kernel/cpu/resctrl/internal.h > @@ -651,6 +651,7 @@ void rdt_domain_reconfigure_cdp(struct rdt_resource *r); > void __init resctrl_file_fflags_init(const char *config, > unsigned long fflags); > void arch_domain_mbm_evt_config(struct rdt_hw_domain *hw_dom); > +ssize_t rdtgroup_assign_abmc(struct rdtgroup *rdtgrp, u32 evtid, int mon_state); > void rdt_staged_configs_clear(void); > bool closid_allocated(unsigned int closid); > int resctrl_find_cleanest_closid(void); > diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c > index 7f54788a58de..cfbdaf8b5f83 100644 > --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c > +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c > @@ -202,6 +202,18 @@ static void assign_cntrs_init(void) > assign_cntrs_free_map_len = r->mbm_assign_cntrs; > } > > +static int assign_cntrs_alloc(void) > +{ > + u32 counterid = ffs(assign_cntrs_free_map); > + > + if (counterid == 0) > + return -ENOSPC; > + counterid--; > + assign_cntrs_free_map &= ~(1 << counterid); > + > + return counterid; Use bitmap API ... eg. find_first_bit() (eliminates need to adjust counterid), __clear_bit() > +} > + > /** > * rdtgroup_mode_by_closid - Return mode of resource group with closid > * @closid: closid if the resource group > @@ -1848,6 +1860,80 @@ static ssize_t mbm_local_bytes_config_write(struct kernfs_open_file *of, > return ret ?: nbytes; > } > > +static void rdtgroup_abmc_msrwrite(void *info) > +{ > + u64 *msrval = info; > + > + wrmsrl(MSR_IA32_L3_QOS_ABMC_CFG, *msrval); > +} > + > +static void rdtgroup_abmc_domain(struct rdt_domain *d, struct rdtgroup *rdtgrp, > + u32 evtid, int index, bool assign) > +{ > + struct rdt_hw_domain *hw_dom = resctrl_to_arch_dom(d); > + union l3_qos_abmc_cfg abmc_cfg = { 0 }; > + struct arch_mbm_state *arch_mbm; > + > + abmc_cfg.split.cfg_en = 1; > + abmc_cfg.split.ctr_en = assign ? 1 : 0; > + abmc_cfg.split.ctr_id = rdtgrp->mon.abmc_ctr_id[index]; > + abmc_cfg.split.bw_src = rdtgrp->mon.rmid; > + > + /* > + * Read the event configuration from the domain and pass it as > + * bw_type. > + */ > + if (evtid == QOS_L3_MBM_TOTAL_EVENT_ID) { > + abmc_cfg.split.bw_type = hw_dom->mbm_total_cfg; > + arch_mbm = &hw_dom->arch_mbm_total[rdtgrp->mon.rmid]; > + } else { > + abmc_cfg.split.bw_type = hw_dom->mbm_local_cfg; > + arch_mbm = &hw_dom->arch_mbm_local[rdtgrp->mon.rmid]; > + } > + > + smp_call_function_any(&d->cpu_mask, rdtgroup_abmc_msrwrite, &abmc_cfg, 1); > + > + /* Reset the internal counters */ > + if (arch_mbm) > + memset(arch_mbm, 0, sizeof(struct arch_mbm_state)); > +} > + > +ssize_t rdtgroup_assign_abmc(struct rdtgroup *rdtgrp, u32 evtid, int mon_state) > +{ > + struct rdt_resource *r = &rdt_resources_all[RDT_RESOURCE_L3].r_resctrl; > + int counterid = 0, index; > + struct rdt_domain *d; > + > + if (rdtgrp->mon.mon_state & mon_state) { > + rdt_last_cmd_puts("ABMC counter is assigned already\n"); > + return 0; > + } > + > + index = mon_event_config_index_get(evtid); > + if (index == INVALID_CONFIG_INDEX) { > + pr_warn_once("Invalid event id %d\n", evtid); > + return -EINVAL; > + } > + > + /* > + * Allocate a new counter and update domains > + */ > + counterid = assign_cntrs_alloc(); > + if (counterid < 0) { > + rdt_last_cmd_puts("Out of ABMC counters\n"); > + return -ENOSPC; > + } > + > + rdtgrp->mon.abmc_ctr_id[index] = counterid; > + > + list_for_each_entry(d, &r->domains, list) > + rdtgroup_abmc_domain(d, rdtgrp, evtid, index, 1); > + > + rdtgrp->mon.mon_state |= mon_state; > + > + return 0; > +} > + > /* rdtgroup information files for one cache resource. */ > static struct rftype res_common_files[] = { > { It is not clear to me where the filesystem and architecture boundaries are, but I understand that you and Peter already discussed this and I look forward to next version that will make this easier to understand. Reinette
