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author | Linus Torvalds <torvalds@linux-foundation.org> | 2020-12-14 13:53:17 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-12-14 13:53:17 -0800 |
commit | 8ba27ae36b416a1507e783dbee4bb521fd6bb519 (patch) | |
tree | c09d559f85d116e6614abde112bd6e6cd9e4c15a /arch/x86/kernel/cpu/resctrl/monitor.c | |
parent | 405f868f13daf7bae85e6fec143121c27d52cdb4 (diff) | |
parent | 19eb86a72df50adcf554f234469bb5b7209b7640 (diff) | |
download | linux-8ba27ae36b416a1507e783dbee4bb521fd6bb519.tar.bz2 |
Merge tag 'x86_cache_for_v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 cache resource control updates from Borislav Petkov:
- add logic to correct MBM total and local values fixing errata SKX99
and BDF102 (Fenghua Yu)
- cleanups
* tag 'x86_cache_for_v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/resctrl: Clean up unused function parameter in rmdir path
x86/resctrl: Constify kernfs_ops
x86/resctrl: Correct MBM total and local values
Documentation/x86: Rename resctrl_ui.rst and add two errata to the file
Diffstat (limited to 'arch/x86/kernel/cpu/resctrl/monitor.c')
-rw-r--r-- | arch/x86/kernel/cpu/resctrl/monitor.c | 82 |
1 files changed, 80 insertions, 2 deletions
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; +} |