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- Add logic to correct MBM total and local values fixing errata SKX99 and BDF102
(Fenghua Yu) - Cleanups. -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEzv7L6UO9uDPlPSfHEsHwGGHeVUoFAl/XhTUACgkQEsHwGGHe VUpTkA/9FNOaJohBa9XO2bv3RjsqE4/2PqZS434HJL6yrbbRDFyscSp2sNCDlfh/ 6zj9R72HpRf6xLW8CTeszrfUQ0z3CFnfwz8EAolhv5DOiJnM3wSS5inmLhtyTMgw mJ8qVXXELdAFm1R8rAQLVmA3FE9aV6u19POstKeXMUykCyaxKDhNLJgn3CiXpegU AvG3QWmrR/1x4DjQguMNwXMQiYVDkRdnfJa5SOzCTwyUj0D0an+kPmSHEMvhaOL6 tUYfjLkZYdB5THG8eUM833EJmgRe7X1VtTQIydcVyt/6tbL50FmVYUpWk+SXuSnJ /uBdzx0IXmfvYKgGSFw+FGOyGH8u02nR4621rECNLNf1h8YknzpN7Ri1hB83GjQe PMiW/gCwxM6gfRsBpJ17xnAbmR5Az2dOz71uj5k13L1GNL8VZD2DZz//a4TDarzE 4R8i3PQ/oUMgmL+ARpVWwycc/dhB8o+1glmAjOwWHO/kM1k/hx9Ou5bbLlhffbL5 zkk6ORrNfKzAMvE1flkjim5XgNHY8n/L4CwBKXJFQ3IYbXBGg0CKxBHWvTpIz1KO O4h52OnYUpM15sY22NSvpdRiHcsgEqNOB4lb6K2dby9iE5b5RHpNgfMNO6+eOtag dgCWopamLK2+MFeNe48+1v/3bDveskhvJon91GUZYmfkFzhZTN8= =9Lsd -----END PGP SIGNATURE----- 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
This commit is contained in:
Linus Torvalds
commit
8ba27ae36b
@ -27,7 +27,7 @@ x86-specific Documentation
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pti
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mds
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microcode
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resctrl_ui
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resctrl
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tsx_async_abort
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usb-legacy-support
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i386/index
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@ -1209,3 +1209,96 @@ View the llc occupancy snapshot::
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# cat /sys/fs/resctrl/p1/mon_data/mon_L3_00/llc_occupancy
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11234000
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Intel RDT Errata
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================
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Intel MBM Counters May Report System Memory Bandwidth Incorrectly
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-----------------------------------------------------------------
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Errata SKX99 for Skylake server and BDF102 for Broadwell server.
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Problem: Intel Memory Bandwidth Monitoring (MBM) counters track metrics
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according to the assigned Resource Monitor ID (RMID) for that logical
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core. The IA32_QM_CTR register (MSR 0xC8E), used to report these
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metrics, may report incorrect system bandwidth for certain RMID values.
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Implication: Due to the errata, system memory bandwidth may not match
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what is reported.
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Workaround: MBM total and local readings are corrected according to the
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following correction factor table:
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+---------------+---------------+---------------+-----------------+
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|core count |rmid count |rmid threshold |correction factor|
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+---------------+---------------+---------------+-----------------+
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|1 |8 |0 |1.000000 |
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+---------------+---------------+---------------+-----------------+
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|2 |16 |0 |1.000000 |
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+---------------+---------------+---------------+-----------------+
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|3 |24 |15 |0.969650 |
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+---------------+---------------+---------------+-----------------+
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|4 |32 |0 |1.000000 |
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+---------------+---------------+---------------+-----------------+
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|6 |48 |31 |0.969650 |
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+---------------+---------------+---------------+-----------------+
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|7 |56 |47 |1.142857 |
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+---------------+---------------+---------------+-----------------+
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|8 |64 |0 |1.000000 |
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+---------------+---------------+---------------+-----------------+
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|9 |72 |63 |1.185115 |
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+---------------+---------------+---------------+-----------------+
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|10 |80 |63 |1.066553 |
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+---------------+---------------+---------------+-----------------+
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|11 |88 |79 |1.454545 |
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+---------------+---------------+---------------+-----------------+
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|12 |96 |0 |1.000000 |
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+---------------+---------------+---------------+-----------------+
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|13 |104 |95 |1.230769 |
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+---------------+---------------+---------------+-----------------+
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|14 |112 |95 |1.142857 |
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+---------------+---------------+---------------+-----------------+
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|15 |120 |95 |1.066667 |
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+---------------+---------------+---------------+-----------------+
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|16 |128 |0 |1.000000 |
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+---------------+---------------+---------------+-----------------+
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|17 |136 |127 |1.254863 |
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+---------------+---------------+---------------+-----------------+
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|18 |144 |127 |1.185255 |
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+---------------+---------------+---------------+-----------------+
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|19 |152 |0 |1.000000 |
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+---------------+---------------+---------------+-----------------+
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|20 |160 |127 |1.066667 |
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+---------------+---------------+---------------+-----------------+
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|21 |168 |0 |1.000000 |
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+---------------+---------------+---------------+-----------------+
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|22 |176 |159 |1.454334 |
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+---------------+---------------+---------------+-----------------+
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|23 |184 |0 |1.000000 |
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+---------------+---------------+---------------+-----------------+
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|24 |192 |127 |0.969744 |
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+---------------+---------------+---------------+-----------------+
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|25 |200 |191 |1.280246 |
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+---------------+---------------+---------------+-----------------+
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|26 |208 |191 |1.230921 |
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+---------------+---------------+---------------+-----------------+
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|27 |216 |0 |1.000000 |
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+---------------+---------------+---------------+-----------------+
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|28 |224 |191 |1.143118 |
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+---------------+---------------+---------------+-----------------+
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If rmid > rmid threshold, MBM total and local values should be multiplied
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by the correction factor.
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See:
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1. Erratum SKX99 in Intel Xeon Processor Scalable Family Specification Update:
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http://web.archive.org/web/20200716124958/https://www.intel.com/content/www/us/en/processors/xeon/scalable/xeon-scalable-spec-update.html
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2. Erratum BDF102 in Intel Xeon E5-2600 v4 Processor Product Family Specification Update:
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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
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3. The errata in Intel Resource Director Technology (Intel RDT) on 2nd Generation Intel Xeon Scalable Processors Reference Manual:
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https://software.intel.com/content/www/us/en/develop/articles/intel-resource-director-technology-rdt-reference-manual.html
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for further information.
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@ -895,6 +895,10 @@ static __init void __check_quirks_intel(void)
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set_rdt_options("!cmt,!mbmtotal,!mbmlocal,!l3cat");
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else
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set_rdt_options("!l3cat");
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fallthrough;
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case INTEL_FAM6_BROADWELL_X:
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intel_rdt_mbm_apply_quirk();
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break;
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}
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}
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@ -264,7 +264,7 @@ void __exit rdtgroup_exit(void);
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struct rftype {
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char *name;
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umode_t mode;
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struct kernfs_ops *kf_ops;
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const struct kernfs_ops *kf_ops;
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unsigned long flags;
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unsigned long fflags;
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@ -619,6 +619,7 @@ void mon_event_read(struct rmid_read *rr, struct rdt_resource *r,
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void mbm_setup_overflow_handler(struct rdt_domain *dom,
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unsigned long delay_ms);
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void mbm_handle_overflow(struct work_struct *work);
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void __init intel_rdt_mbm_apply_quirk(void);
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bool is_mba_sc(struct rdt_resource *r);
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void setup_default_ctrlval(struct rdt_resource *r, u32 *dc, u32 *dm);
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u32 delay_bw_map(unsigned long bw, struct rdt_resource *r);
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@ -64,6 +64,69 @@ unsigned int rdt_mon_features;
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*/
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unsigned int resctrl_cqm_threshold;
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#define CF(cf) ((unsigned long)(1048576 * (cf) + 0.5))
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/*
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* The correction factor table is documented in Documentation/x86/resctrl.rst.
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* If rmid > rmid threshold, MBM total and local values should be multiplied
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* by the correction factor.
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*
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* The original table is modified for better code:
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*
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* 1. The threshold 0 is changed to rmid count - 1 so don't do correction
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* for the case.
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* 2. MBM total and local correction table indexed by core counter which is
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* equal to (x86_cache_max_rmid + 1) / 8 - 1 and is from 0 up to 27.
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* 3. The correction factor is normalized to 2^20 (1048576) so it's faster
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* to calculate corrected value by shifting:
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* corrected_value = (original_value * correction_factor) >> 20
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*/
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static const struct mbm_correction_factor_table {
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u32 rmidthreshold;
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u64 cf;
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} mbm_cf_table[] __initdata = {
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{7, CF(1.000000)},
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{15, CF(1.000000)},
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{15, CF(0.969650)},
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{31, CF(1.000000)},
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{31, CF(1.066667)},
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{31, CF(0.969650)},
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{47, CF(1.142857)},
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{63, CF(1.000000)},
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{63, CF(1.185115)},
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{63, CF(1.066553)},
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{79, CF(1.454545)},
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{95, CF(1.000000)},
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{95, CF(1.230769)},
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{95, CF(1.142857)},
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{95, CF(1.066667)},
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{127, CF(1.000000)},
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{127, CF(1.254863)},
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{127, CF(1.185255)},
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{151, CF(1.000000)},
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{127, CF(1.066667)},
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{167, CF(1.000000)},
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{159, CF(1.454334)},
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{183, CF(1.000000)},
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{127, CF(0.969744)},
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{191, CF(1.280246)},
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{191, CF(1.230921)},
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{215, CF(1.000000)},
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{191, CF(1.143118)},
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};
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static u32 mbm_cf_rmidthreshold __read_mostly = UINT_MAX;
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static u64 mbm_cf __read_mostly;
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static inline u64 get_corrected_mbm_count(u32 rmid, unsigned long val)
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{
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/* Correct MBM value. */
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if (rmid > mbm_cf_rmidthreshold)
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val = (val * mbm_cf) >> 20;
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return val;
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}
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static inline struct rmid_entry *__rmid_entry(u32 rmid)
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{
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struct rmid_entry *entry;
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@ -260,7 +323,8 @@ static int __mon_event_count(u32 rmid, struct rmid_read *rr)
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m->chunks += chunks;
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m->prev_msr = tval;
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rr->val += m->chunks;
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rr->val += get_corrected_mbm_count(rmid, m->chunks);
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return 0;
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}
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@ -279,7 +343,7 @@ static void mbm_bw_count(u32 rmid, struct rmid_read *rr)
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return;
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chunks = mbm_overflow_count(m->prev_bw_msr, tval, rr->r->mbm_width);
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cur_bw = (chunks * r->mon_scale) >> 20;
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cur_bw = (get_corrected_mbm_count(rmid, chunks) * r->mon_scale) >> 20;
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if (m->delta_comp)
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m->delta_bw = abs(cur_bw - m->prev_bw);
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@ -642,3 +706,17 @@ int rdt_get_mon_l3_config(struct rdt_resource *r)
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return 0;
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}
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void __init intel_rdt_mbm_apply_quirk(void)
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{
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int cf_index;
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cf_index = (boot_cpu_data.x86_cache_max_rmid + 1) / 8 - 1;
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if (cf_index >= ARRAY_SIZE(mbm_cf_table)) {
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pr_info("No MBM correction factor available\n");
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return;
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}
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mbm_cf_rmidthreshold = mbm_cf_table[cf_index].rmidthreshold;
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mbm_cf = mbm_cf_table[cf_index].cf;
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}
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@ -240,13 +240,13 @@ static ssize_t rdtgroup_file_write(struct kernfs_open_file *of, char *buf,
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return -EINVAL;
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}
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static struct kernfs_ops rdtgroup_kf_single_ops = {
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static const struct kernfs_ops rdtgroup_kf_single_ops = {
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.atomic_write_len = PAGE_SIZE,
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.write = rdtgroup_file_write,
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.seq_show = rdtgroup_seqfile_show,
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};
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static struct kernfs_ops kf_mondata_ops = {
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static const struct kernfs_ops kf_mondata_ops = {
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.atomic_write_len = PAGE_SIZE,
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.seq_show = rdtgroup_mondata_show,
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};
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@ -3023,8 +3023,7 @@ static int rdtgroup_mkdir(struct kernfs_node *parent_kn, const char *name,
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return -EPERM;
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}
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static int rdtgroup_rmdir_mon(struct kernfs_node *kn, struct rdtgroup *rdtgrp,
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cpumask_var_t tmpmask)
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static int rdtgroup_rmdir_mon(struct rdtgroup *rdtgrp, cpumask_var_t tmpmask)
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{
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struct rdtgroup *prdtgrp = rdtgrp->mon.parent;
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int cpu;
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@ -3056,8 +3055,7 @@ static int rdtgroup_rmdir_mon(struct kernfs_node *kn, struct rdtgroup *rdtgrp,
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return 0;
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}
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static int rdtgroup_ctrl_remove(struct kernfs_node *kn,
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struct rdtgroup *rdtgrp)
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static int rdtgroup_ctrl_remove(struct rdtgroup *rdtgrp)
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{
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rdtgrp->flags = RDT_DELETED;
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list_del(&rdtgrp->rdtgroup_list);
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@ -3066,8 +3064,7 @@ static int rdtgroup_ctrl_remove(struct kernfs_node *kn,
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return 0;
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}
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static int rdtgroup_rmdir_ctrl(struct kernfs_node *kn, struct rdtgroup *rdtgrp,
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cpumask_var_t tmpmask)
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static int rdtgroup_rmdir_ctrl(struct rdtgroup *rdtgrp, cpumask_var_t tmpmask)
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{
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int cpu;
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@ -3094,7 +3091,7 @@ static int rdtgroup_rmdir_ctrl(struct kernfs_node *kn, struct rdtgroup *rdtgrp,
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closid_free(rdtgrp->closid);
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free_rmid(rdtgrp->mon.rmid);
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rdtgroup_ctrl_remove(kn, rdtgrp);
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rdtgroup_ctrl_remove(rdtgrp);
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/*
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* Free all the child monitor group rmids.
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@ -3131,13 +3128,13 @@ static int rdtgroup_rmdir(struct kernfs_node *kn)
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rdtgrp != &rdtgroup_default) {
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if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP ||
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rdtgrp->mode == RDT_MODE_PSEUDO_LOCKED) {
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ret = rdtgroup_ctrl_remove(kn, rdtgrp);
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ret = rdtgroup_ctrl_remove(rdtgrp);
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} else {
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ret = rdtgroup_rmdir_ctrl(kn, rdtgrp, tmpmask);
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ret = rdtgroup_rmdir_ctrl(rdtgrp, tmpmask);
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}
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} else if (rdtgrp->type == RDTMON_GROUP &&
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is_mon_groups(parent_kn, kn->name)) {
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ret = rdtgroup_rmdir_mon(kn, rdtgrp, tmpmask);
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ret = rdtgroup_rmdir_mon(rdtgrp, tmpmask);
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} else {
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ret = -EPERM;
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}
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