diff options
| -rw-r--r-- | Documentation/x86/index.rst | 2 | ||||
| -rw-r--r-- | Documentation/x86/resctrl.rst (renamed from Documentation/x86/resctrl_ui.rst) | 93 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/resctrl/core.c | 4 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/resctrl/internal.h | 3 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/resctrl/monitor.c | 82 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/resctrl/rdtgroup.c | 21 |
6 files changed, 189 insertions, 16 deletions
diff --git a/Documentation/x86/index.rst b/Documentation/x86/index.rst index 647a570d4931..e7eb84484ddc 100644 --- a/Documentation/x86/index.rst +++ b/Documentation/x86/index.rst @@ -27,7 +27,7 @@ x86-specific Documentation pti mds microcode - resctrl_ui + resctrl tsx_async_abort usb-legacy-support i386/index diff --git a/Documentation/x86/resctrl_ui.rst b/Documentation/x86/resctrl.rst index e59b7b93a9b4..71a531061e4e 100644 --- a/Documentation/x86/resctrl_ui.rst +++ b/Documentation/x86/resctrl.rst @@ -1209,3 +1209,96 @@ View the llc occupancy snapshot:: # cat /sys/fs/resctrl/p1/mon_data/mon_L3_00/llc_occupancy 11234000 + +Intel RDT Errata +================ + +Intel MBM Counters May Report System Memory Bandwidth Incorrectly +----------------------------------------------------------------- + +Errata SKX99 for Skylake server and BDF102 for Broadwell server. + +Problem: Intel Memory Bandwidth Monitoring (MBM) counters track metrics +according to the assigned Resource Monitor ID (RMID) for that logical +core. The IA32_QM_CTR register (MSR 0xC8E), used to report these +metrics, may report incorrect system bandwidth for certain RMID values. + +Implication: Due to the errata, system memory bandwidth may not match +what is reported. + +Workaround: MBM total and local readings are corrected according to the +following correction factor table: + ++---------------+---------------+---------------+-----------------+ +|core count |rmid count |rmid threshold |correction factor| ++---------------+---------------+---------------+-----------------+ +|1 |8 |0 |1.000000 | ++---------------+---------------+---------------+-----------------+ +|2 |16 |0 |1.000000 | ++---------------+---------------+---------------+-----------------+ +|3 |24 |15 |0.969650 | ++---------------+---------------+---------------+-----------------+ +|4 |32 |0 |1.000000 | ++---------------+---------------+---------------+-----------------+ +|6 |48 |31 |0.969650 | ++---------------+---------------+---------------+-----------------+ +|7 |56 |47 |1.142857 | ++---------------+---------------+---------------+-----------------+ +|8 |64 |0 |1.000000 | ++---------------+---------------+---------------+-----------------+ +|9 |72 |63 |1.185115 | ++---------------+---------------+---------------+-----------------+ +|10 |80 |63 |1.066553 | ++---------------+---------------+---------------+-----------------+ +|11 |88 |79 |1.454545 | ++---------------+---------------+---------------+-----------------+ +|12 |96 |0 |1.000000 | ++---------------+---------------+---------------+-----------------+ +|13 |104 |95 |1.230769 | ++---------------+---------------+---------------+-----------------+ +|14 |112 |95 |1.142857 | ++---------------+---------------+---------------+-----------------+ +|15 |120 |95 |1.066667 | ++---------------+---------------+---------------+-----------------+ +|16 |128 |0 |1.000000 | ++---------------+---------------+---------------+-----------------+ +|17 |136 |127 |1.254863 | ++---------------+---------------+---------------+-----------------+ +|18 |144 |127 |1.185255 | ++---------------+---------------+---------------+-----------------+ +|19 |152 |0 |1.000000 | ++---------------+---------------+---------------+-----------------+ +|20 |160 |127 |1.066667 | ++---------------+---------------+---------------+-----------------+ +|21 |168 |0 |1.000000 | ++---------------+---------------+---------------+-----------------+ +|22 |176 |159 |1.454334 | ++---------------+---------------+---------------+-----------------+ +|23 |184 |0 |1.000000 | ++---------------+---------------+---------------+-----------------+ +|24 |192 |127 |0.969744 | ++---------------+---------------+---------------+-----------------+ +|25 |200 |191 |1.280246 | ++---------------+---------------+---------------+-----------------+ +|26 |208 |191 |1.230921 | ++---------------+---------------+---------------+-----------------+ +|27 |216 |0 |1.000000 | ++---------------+---------------+---------------+-----------------+ +|28 |224 |191 |1.143118 | ++---------------+---------------+---------------+-----------------+ + +If rmid > rmid threshold, MBM total and local values should be multiplied +by the correction factor. + +See: + +1. Erratum SKX99 in Intel Xeon Processor Scalable Family Specification Update: +http://web.archive.org/web/20200716124958/https://www.intel.com/content/www/us/en/processors/xeon/scalable/xeon-scalable-spec-update.html + +2. Erratum BDF102 in Intel Xeon E5-2600 v4 Processor Product Family Specification Update: +http://web.archive.org/web/20191125200531/https://www.intel.com/content/dam/www/public/us/en/documents/specification-updates/xeon-e5-v4-spec-update.pdf + +3. The errata in Intel Resource Director Technology (Intel RDT) on 2nd Generation Intel Xeon Scalable Processors Reference Manual: +https://software.intel.com/content/www/us/en/develop/articles/intel-resource-director-technology-rdt-reference-manual.html + +for further information. diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c index e8b5f1cf1ae8..698bb26aeb6e 100644 --- a/arch/x86/kernel/cpu/resctrl/core.c +++ b/arch/x86/kernel/cpu/resctrl/core.c @@ -895,6 +895,10 @@ static __init void __check_quirks_intel(void) set_rdt_options("!cmt,!mbmtotal,!mbmlocal,!l3cat"); else set_rdt_options("!l3cat"); + fallthrough; + case INTEL_FAM6_BROADWELL_X: + intel_rdt_mbm_apply_quirk(); + break; } } diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h index f65d3c0dbc41..ee71c47844cb 100644 --- a/arch/x86/kernel/cpu/resctrl/internal.h +++ b/arch/x86/kernel/cpu/resctrl/internal.h @@ -264,7 +264,7 @@ void __exit rdtgroup_exit(void); struct rftype { char *name; umode_t mode; - struct kernfs_ops *kf_ops; + const struct kernfs_ops *kf_ops; unsigned long flags; unsigned long fflags; @@ -619,6 +619,7 @@ void mon_event_read(struct rmid_read *rr, struct rdt_resource *r, void mbm_setup_overflow_handler(struct rdt_domain *dom, unsigned long delay_ms); void mbm_handle_overflow(struct work_struct *work); +void __init intel_rdt_mbm_apply_quirk(void); bool is_mba_sc(struct rdt_resource *r); void setup_default_ctrlval(struct rdt_resource *r, u32 *dc, u32 *dm); u32 delay_bw_map(unsigned long bw, struct rdt_resource *r); diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c index a98519a3a2e6..7ac31210e452 100644 --- a/arch/x86/kernel/cpu/resctrl/monitor.c +++ b/arch/x86/kernel/cpu/resctrl/monitor.c @@ -64,6 +64,69 @@ unsigned int rdt_mon_features; */ unsigned int resctrl_cqm_threshold; +#define CF(cf) ((unsigned long)(1048576 * (cf) + 0.5)) + +/* + * The correction factor table is documented in Documentation/x86/resctrl.rst. + * If rmid > rmid threshold, MBM total and local values should be multiplied + * by the correction factor. + * + * The original table is modified for better code: + * + * 1. The threshold 0 is changed to rmid count - 1 so don't do correction + * for the case. + * 2. MBM total and local correction table indexed by core counter which is + * equal to (x86_cache_max_rmid + 1) / 8 - 1 and is from 0 up to 27. + * 3. The correction factor is normalized to 2^20 (1048576) so it's faster + * to calculate corrected value by shifting: + * corrected_value = (original_value * correction_factor) >> 20 + */ +static const struct mbm_correction_factor_table { + u32 rmidthreshold; + u64 cf; +} mbm_cf_table[] __initdata = { + {7, CF(1.000000)}, + {15, CF(1.000000)}, + {15, CF(0.969650)}, + {31, CF(1.000000)}, + {31, CF(1.066667)}, + {31, CF(0.969650)}, + {47, CF(1.142857)}, + {63, CF(1.000000)}, + {63, CF(1.185115)}, + {63, CF(1.066553)}, + {79, CF(1.454545)}, + {95, CF(1.000000)}, + {95, CF(1.230769)}, + {95, CF(1.142857)}, + {95, CF(1.066667)}, + {127, CF(1.000000)}, + {127, CF(1.254863)}, + {127, CF(1.185255)}, + {151, CF(1.000000)}, + {127, CF(1.066667)}, + {167, CF(1.000000)}, + {159, CF(1.454334)}, + {183, CF(1.000000)}, + {127, CF(0.969744)}, + {191, CF(1.280246)}, + {191, CF(1.230921)}, + {215, CF(1.000000)}, + {191, CF(1.143118)}, +}; + +static u32 mbm_cf_rmidthreshold __read_mostly = UINT_MAX; +static u64 mbm_cf __read_mostly; + +static inline u64 get_corrected_mbm_count(u32 rmid, unsigned long val) +{ + /* Correct MBM value. */ + if (rmid > mbm_cf_rmidthreshold) + val = (val * mbm_cf) >> 20; + + return val; +} + static inline struct rmid_entry *__rmid_entry(u32 rmid) { struct rmid_entry *entry; @@ -260,7 +323,8 @@ static int __mon_event_count(u32 rmid, struct rmid_read *rr) m->chunks += chunks; m->prev_msr = tval; - rr->val += m->chunks; + rr->val += get_corrected_mbm_count(rmid, m->chunks); + return 0; } @@ -279,7 +343,7 @@ static void mbm_bw_count(u32 rmid, struct rmid_read *rr) return; chunks = mbm_overflow_count(m->prev_bw_msr, tval, rr->r->mbm_width); - cur_bw = (chunks * r->mon_scale) >> 20; + cur_bw = (get_corrected_mbm_count(rmid, chunks) * r->mon_scale) >> 20; if (m->delta_comp) m->delta_bw = abs(cur_bw - m->prev_bw); @@ -642,3 +706,17 @@ int rdt_get_mon_l3_config(struct rdt_resource *r) return 0; } + +void __init intel_rdt_mbm_apply_quirk(void) +{ + int cf_index; + + cf_index = (boot_cpu_data.x86_cache_max_rmid + 1) / 8 - 1; + if (cf_index >= ARRAY_SIZE(mbm_cf_table)) { + pr_info("No MBM correction factor available\n"); + return; + } + + mbm_cf_rmidthreshold = mbm_cf_table[cf_index].rmidthreshold; + mbm_cf = mbm_cf_table[cf_index].cf; +} diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c index f3418428682b..29ffb95b25ff 100644 --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c @@ -240,13 +240,13 @@ static ssize_t rdtgroup_file_write(struct kernfs_open_file *of, char *buf, return -EINVAL; } -static struct kernfs_ops rdtgroup_kf_single_ops = { +static const struct kernfs_ops rdtgroup_kf_single_ops = { .atomic_write_len = PAGE_SIZE, .write = rdtgroup_file_write, .seq_show = rdtgroup_seqfile_show, }; -static struct kernfs_ops kf_mondata_ops = { +static const struct kernfs_ops kf_mondata_ops = { .atomic_write_len = PAGE_SIZE, .seq_show = rdtgroup_mondata_show, }; @@ -3023,8 +3023,7 @@ static int rdtgroup_mkdir(struct kernfs_node *parent_kn, const char *name, return -EPERM; } -static int rdtgroup_rmdir_mon(struct kernfs_node *kn, struct rdtgroup *rdtgrp, - cpumask_var_t tmpmask) +static int rdtgroup_rmdir_mon(struct rdtgroup *rdtgrp, cpumask_var_t tmpmask) { struct rdtgroup *prdtgrp = rdtgrp->mon.parent; int cpu; @@ -3056,8 +3055,7 @@ static int rdtgroup_rmdir_mon(struct kernfs_node *kn, struct rdtgroup *rdtgrp, return 0; } -static int rdtgroup_ctrl_remove(struct kernfs_node *kn, - struct rdtgroup *rdtgrp) +static int rdtgroup_ctrl_remove(struct rdtgroup *rdtgrp) { rdtgrp->flags = RDT_DELETED; list_del(&rdtgrp->rdtgroup_list); @@ -3066,8 +3064,7 @@ static int rdtgroup_ctrl_remove(struct kernfs_node *kn, return 0; } -static int rdtgroup_rmdir_ctrl(struct kernfs_node *kn, struct rdtgroup *rdtgrp, - cpumask_var_t tmpmask) +static int rdtgroup_rmdir_ctrl(struct rdtgroup *rdtgrp, cpumask_var_t tmpmask) { int cpu; @@ -3094,7 +3091,7 @@ static int rdtgroup_rmdir_ctrl(struct kernfs_node *kn, struct rdtgroup *rdtgrp, closid_free(rdtgrp->closid); free_rmid(rdtgrp->mon.rmid); - rdtgroup_ctrl_remove(kn, rdtgrp); + rdtgroup_ctrl_remove(rdtgrp); /* * Free all the child monitor group rmids. @@ -3131,13 +3128,13 @@ static int rdtgroup_rmdir(struct kernfs_node *kn) rdtgrp != &rdtgroup_default) { if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP || rdtgrp->mode == RDT_MODE_PSEUDO_LOCKED) { - ret = rdtgroup_ctrl_remove(kn, rdtgrp); + ret = rdtgroup_ctrl_remove(rdtgrp); } else { - ret = rdtgroup_rmdir_ctrl(kn, rdtgrp, tmpmask); + ret = rdtgroup_rmdir_ctrl(rdtgrp, tmpmask); } } else if (rdtgrp->type == RDTMON_GROUP && is_mon_groups(parent_kn, kn->name)) { - ret = rdtgroup_rmdir_mon(kn, rdtgrp, tmpmask); + ret = rdtgroup_rmdir_mon(rdtgrp, tmpmask); } else { ret = -EPERM; } |