# SuperMicro Skylake Servers - HW and BIOS Configuration
1. [Linux lscpu](#linux-lscpu)
1. [Linux dmidecode](#dmidecode)
1. [Xeon Skx Server BIOS Configuration](#xeon-skx-server-bios-configuration)
1. [Boot Feature](#boot-feature)
1. [CPU Configuration](#cpu-configuration)
1. [Advanced Power Management Configuration](#advanced-power-management-configuration)
1. [CPU P State Control](#cpu-p-state-control)
1. [Hardware PM State Control](#hardware-pm-state-control)
1. [CPU C State Control](#cpu-c-state-control)
1. [Package C State Control](#package-c-state-control)
1. [CPU T State Control](#cpu-t-state-control)
1. [Chipset Configuration](#chipset-configuration)
1. [North Bridge](#north-bridge)
1. [UPI Configuration](#upi-configuration)
1. [Memory Configuration](#memory-configuration)
1. [IIO Configuration](#iio-configuration)
1. [CPU1 Configuration](#cpu1-configuration)
1. [CPU2 Configuration](#cpu2-configuration)
1. [South Bridge](#south-bridge)
1. [PCIe/PCI/PnP Configuration](#pciepcipnp-configuration)
1. [ACPI Settings](#acpi-settings)
1. [Xeon Skx Server Firmware Inventory](#xeon-skx-server-firmware-inventory)
## Linux lscpu
```
$ lscpu
Architecture: x86_64
CPU op-mode(s): 32-bit, 64-bit
Byte Order: Little Endian
CPU(s): 112
On-line CPU(s) list: 0-111
Thread(s) per core: 2
Core(s) per socket: 28
Socket(s): 2
NUMA node(s): 2
Vendor ID: GenuineIntel
CPU family: 6
Model: 85
Model name: Intel(R) Xeon(R) Platinum 8180 CPU @ 2.50GHz
Stepping: 4
CPU MHz: 2500.550
BogoMIPS: 5000.00
Virtualization: VT-x
L1d cache: 32K
L1i cache: 32K
L2 cache: 1024K
L3 cache: 39424K
NUMA node0 CPU(s): 0-27,56-83
NUMA node1 CPU(s): 28-55,84-111
Flags: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca
cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx
pdpe1gb rdtscp lm constant_tsc art arch_perfmon pebs bts rep_good nopl xtopology
nonstop_tsc cpuid aperfmperf pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2
ssse3 sdbg fma cx16 xtpr pdcm pcid dca sse4_1 sse4_2 x2apic movbe popcnt
tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm abm 3dnowprefetch
cpuid_fault epb cat_l3 cdp_l3 invpcid_single pti ssbd mba ibrs ibpb stibp
tpr_shadow vnmi flexpriority ept vpid fsgsbase tsc_adjustbmi1 hle avx2 smep bmi2
erms invpcid rtm cqm mpx rdt_a avx512f avx512dq rdseed adx smap clflushopt clwb
intel_pt avx512cd avx512bw avx512vl xsaveopt xsavec xgetbv1 xsaves cqm_llc
cqm_occup_llc cqm_mbm_total cqm_mbm_local dtherm ida arat pln pts pku ospke
md_clear flush_l1d
```
### Linux dmidecode
```
$ dmidecode
# dmidecode 3.1
Getting SMBIOS data from sysfs.
SMBIOS 3.2.1 present.
Table at 0x6F388000.
Handle 0x0000, DMI type 0, 26 bytes
BIOS Information
Vendor: American Megatrends Inc.
Version: 3.2
Release Date: 10/18/2019
Address: 0xF0000
Runtime Size: 64 kB
ROM Size: 64 MB
Characteristics:
PCI is supported
BIOS is upgradeable
BIOS shadowing is allowed
Boot from CD is supported
Selectable boot is supported
BIOS ROM is socketed
EDD is supported
5.25"/1.2 MB floppy services are supported (int 13h)
3.5"/720 kB floppy services are supported (int 13h)
3.5"/2.88 MB floppy services are supported (int 13h)
Print screen service is supported (int 5h)
Serial services are supported (int 14h)
Printer services are supported (int 17h)
ACPI is supported
USB legacy is supported
BIOS boot specification is supported
Targeted content distribution is supported
UEFI is supported
BIOS Revision: 5.14
Handle 0x0001, DMI type 1, 27 bytes
System Information
Manufacturer: Supermicro
Product Name: SYS-7049GP-TRT
Version: 0123456789
Serial Number: S291427X8332242
UUID: 00000000-0000-0000-0000-AC1F6B8A8DB6
Wake-up Type: Power Switch
SKU Number: To be filled by O.E.M.
Family: To be filled by O.E.M.
Handle 0x0002, DMI type 2, 15 bytes
Base Board Information
Manufacturer: Supermicro
Product Name: X11DPG-QT
Version: 1.02
Serial Number: VM183S014930
Asset Tag: To be filled by O.E.M.
Features:
Board is a hosting board
Board is replaceable
Location In Chassis: To be filled by O.E.M.
Chassis Handle: 0x0003
Type: Motherboard
Contained Object Handles: 0
Handle 0x0003, DMI type 3, 22 bytes
Chassis Information
Manufacturer: Supermicro
Type: Other
Lock: Not Present
Version: 0123456789
Serial Number: C7470KH06A20167
Asset Tag: To be filled by O.E.M.
Boot-up State: Safe
Power Supply State: Safe
Thermal State: Safe
Security Status: None
OEM Information: 0x00000000
Handle 0x0050, DMI type 4, 48 bytes
Processor Information
Socket Designation: CPU1
Type: Central Processor
Family: Xeon
Manufacturer: Intel(R) Corporation
ID: 54 06 05 00 FF FB EB BF
Signature: Type 0, Family 6, Model 85, Stepping 4
Flags:
FPU (Floating-point unit on-chip)
VME (Virtual mode extension)
DE (Debugging extension)
PSE (Page size extension)
TSC (Time stamp counter)
MSR (Model specific registers)
PAE (Physical address extension)
MCE (Machine check exception)
CX8 (CMPXCHG8 instruction supported)
APIC (On-chip APIC hardware supported)
SEP (Fast system call)
MTRR (Memory type range registers)
PGE (Page global enable)
MCA (Machine check architecture)
CMOV (Conditional move instruction supported)
PAT (Page attribute table)
PSE-36 (36-bit page size extension)
CLFSH (CLFLUSH instruction supported)
DS (Debug store)
ACPI (ACPI supported)
MMX (MMX technology supported)
FXSR (FXSAVE and FXSTOR instructions supported)
SSE (Streaming SIMD extensions)
SSE2 (Streaming SIMD extensions 2)
SS (Self-snoop)
HTT (Multi-threading)
TM (Thermal monitor supported)
PBE (Pending break enabled)
Version: Intel(R) Xeon(R) Platinum 8180 CPU @ 2.50GHz
Voltage: 1.6 V
External Clock: 100 MHz
Max Speed: 4000 MHz
Current Speed: 2500 MHz
Status: Populated, Enabled
Upgrade: Other
L1 Cache Handle: 0x004D
L2 Cache Handle: 0x004E
L3 Cache Handle: 0x004F
Serial Number: Not Specified
Asset Tag: UNKNOWN
Part Number: Not Specified
Core Count: 28
Core Enabled: 28
Thread Count: 56
Characteristics:
64-bit capable
Multi-Core
Hardware Thread
Execute Protection
Enhanced Virtualization
Power/Performance Control
Handle 0x0054, DMI type 4, 48 bytes
Processor Information
Socket Designation: CPU2
Type: Central Processor
Family: Xeon
Manufacturer: Intel(R) Corporation
ID: 54 06 05 00 FF FB EB BF
Signature: Type 0, Family 6, Model 85, Stepping 4
Flags:
FPU (Floating-point unit on-chip)
VME (Virtual mode extension)
DE (Debugging extension)
PSE (Page size extension)
TSC (Time stamp counter)
MSR (Model specific registers)
PAE (Physical address extension)
MCE (Machine check exception)
CX8 (CMPXCHG8 instruction supported)
APIC (On-chip APIC hardware supported)
SEP (Fast system call)
MTRR (Memory type range registers)
PGE (Page global enable)
MCA (Machine check architecture)
CMOV (Conditional move instruction supported)
PAT (Page attribute table)
PSE-36 (36-bit page size extension)
CLFSH (CLFLUSH instruction supported)
DS (Debug store)
ACPI (ACPI supported)
MMX (MMX technology supported)
FXSR (FXSAVE and FXSTOR instructions supported)
SSE (Streaming SIMD extensions)
SSE2 (Streaming SIMD extensions 2)
SS (Self-snoop)
HTT (Multi-threading)
TM (Thermal monitor supported)
PBE (Pending break enabled)
Version: Intel(R) Xeon(R) Platinum 8180 CPU @ 2.50GHz
Voltage: 1.6 V
External Clock: 100 MHz
Max Speed: 4000 MHz
Current Speed: 2500 MHz
Status: Populated, Enabled
Upgrade: Other
L1 Cache Handle: 0x0051
L2 Cache Handle: 0x0052
L3 Cache Handle: 0x0053
Serial Number: Not Specified
Asset Tag: UNKNOWN
Part Number: Not Specified
Core Count: 28
Core Enabled: 28
Thread Count: 56
Characteristics:
64-bit capable
Multi-Core
Hardware Thread
Execute Protection
Enhanced Virtualization
Power/Performance Control
```
## Xeon Skx Server BIOS Configuration
### Boot Feature
```
| Quiet Boot [Enabled] |Boot option |
| | |
| Option ROM Messages [Force BIOS] | |
| Bootup NumLock State [On] | |
| Wait For "F1" If Error [Enabled] | |
| INT19 Trap Response [Immediate] | |
| Re-try Boot [Disabled] | |
| Install Windows 7 USB support [Disabled] | |
| Port 61h Bit-4 Emulation [Disabled] | |
| | |
| Power Configuration | |
| Watch Dog Function [Disabled] | |
| Restore on AC Power Loss [Last State] | |
| Power Button Function [Instant Off] | |
| Throttle on Power Fail [Disabled] | |
```
### CPU Configuration
```
| Processor Configuration |Enables Hyper Threading |
| -------------------------------------------------- |(Software Method to |
| Processor BSP Revision 50654 - SKX H0 |Enable/Disable Logical |
| Processor Socket CPU1 | CPU2 |Processor threads. |
| Processor ID 00050654* | 000506... | |
| Processor Frequency 2.500GHz | 2.500GHz | |
| Processor Max Ratio 19H | 19H | |
| Processor Min Ratio 0AH | 0AH | |
| Microcode Revision 02000054 | 02000054 | |
| L1 Cache RAM 64KB | 64KB | |
| L2 Cache RAM 1024KB | 1024KB | |
| L3 Cache RAM 39424KB | 39424KB | |
| Processor 0 Version | |
| Intel(R) Xeon(R) Platinum 8180 CPU @ 2.50GHz | |
| Processor 1 Version | |
| Intel(R) Xeon(R) Platinum 8180 CPU @ 2.50GHz | |
| | |
| Hyper-Threading [ALL] [Enable] | |
| Core Enabled 0 | |
| Monitor/Mwait [Auto] | |
| Execute Disable Bit [Enable] | |
| Intel Virtualization Technology [Enable] | |
| PPIN Control [Unlock/Enable] | |
| Hardware Prefetcher [Enable] | |
| Adjacent Cache Prefetch [Enable] | |
| DCU Streamer Prefetcher [Enable] | |
| DCU IP Prefetcher [Enable] | |
| LLC Prefetch [Disable] | |
| Extended APIC [Disable] | |
| AES-NI [Enable] | |
|> Advanced Power Management Configuration | |
```
#### Advanced Power Management Configuration
```
| Advanced Power Management Configuration |Switch CPU Power Management |
| -------------------------------------------------- |profile |
| Power Technology [Custom] | |
| Power Performance Tuning [BIOS Controls EPB] | |
| ENERGY_PERF_BIAS_CFG mode [Maximum Performance] | |
|> CPU P State Control | |
|> Hardware PM State Control | |
|> CPU C State Control | |
|> Package C State Control | |
|> CPU T State Control | |
```
##### CPU P State Control
```
| CPU P State Control |Enable/Disable EIST |
| |(P-States) |
| SpeedStep (Pstates) [Disable] | |
| EIST PSD Function [HW_ALL] | |
```
##### Hardware PM State Control
```
| Hardware PM State Control |Disable: Hardware chooses a |
| |P-state based on OS Request |
| Hardware P-States [Disable] |(Legacy P-States) |
| |Native Mode:Hardware |
| |chooses a P-state based on |
| |OS guidance |
| |Out of Band Mode:Hardware |
| |autonomously chooses a |
| |P-state (no OS guidance) |
```
##### CPU C State Control
```
| CPU C State Control |Autonomous Core C-State |
| |Control |
| Autonomous Core C-State [Disable] | |
| CPU C6 report [Disable] | |
| Enhanced Halt State (C1E) [Disable] | |
```
##### Package C State Control
```
| Package C State Control |Package C State limit |
| | |
| Package C State [C0/C1 state] | |
```
##### CPU T State Control
```
| CPU T State Control |Enable/Disable Software |
| |Controlled T-States |
| Software Controlled T-States [Disable] | |
```
#### Chipset Configuration
```
| WARNING: Setting wrong values in below sections may cause |North Bridge Parameters |
| system to malfunction. | |
|> North Bridge | |
|> South Bridge | |
```
##### North Bridge
```
|> UPI Configuration |Displays and provides |
|> Memory Configuration |option to change the UPI |
|> IIO Configuration |Settings |
```
##### UPI Configuration
```
| UPI Configuration |Choose Topology Precedence |
| -------------------------------------------------- |to degrade features if |
| Number of CPU 2 |system options are in |
| Number of Active UPI Link 3 |conflict or choose Feature |
| Current UPI Link Speed Fast |Precedence to degrade |
| Current UPI Link Frequency 10.4 GT/s |topology if system options |
| UPI Global MMIO Low Base / Limit 90000000 / FBFFFFFF |are in conflict. |
| UPI Global MMIO High Base / Limit 0000000000000000 / ... | |
| UPI Pci-e Configuration Base / Size 80000000 / 10000000 | |
| Degrade Precedence [Topology Precedence] | |
| Link L0p Enable [Disable] | |
| Link L1 Enable [Disable] | |
| IO Directory Cache (IODC) [Auto] | |
| SNC [Disable] | |
| XPT Prefetch [Disable] | |
| KTI Prefetch [Enable] | |
| Local/Remote Threshold [Auto] | |
| Stale AtoS [Disable] | |
| LLC dead line alloc [Enable] | |
| Isoc Mode [Auto] | |
```
##### Memory Configuration
```
| |POR - Enforces Plan Of |
| -------------------------------------------------- |Record restrictions for |
| Integrated Memory Controller (iMC) |DDR4 frequency and voltage |
| -------------------------------------------------- |programming. Disable - |
| |Disables this feature. |
| Enforce POR [POR] | |
| PPR Type [Hard PPR] | |
| Enhanced PPR [Disable] | |
| Operation Mode [Test and Repair] | |
| Memory Frequency [2933] | |
| Data Scrambling for DDR4 [Auto] | |
| tCCD_L Relaxation [Auto] | |
| tRWSR Relaxation [Disable] | |
| tRFC Optimization for 16Gb Based DIMM [Force 550ns] | |
| 2x Refresh [Auto] | |
| Page Policy [Auto] | |
| IMC Interleaving [2-way Interleave] | |
|> Memory Topology | |
|> Memory RAS Configuration | |
```
##### IIO Configuration
```
| IIO Configuration |Expose IIO DFX devices and |
| -------------------------------------------------- |other CPU devices like PMON |
| | |
| EV DFX Features [Disable] | |
|> CPU1 Configuration | |
|> CPU2 Configuration | |
|> IOAT Configuration | |
|> Intel. VT for Directed I/O (VT-d) | |
|> Intel. VMD technology | |
| | |
| IIO-PCIE Express Global Options | |
| ======================================== | |
| PCI-E Completion Timeout Disable [No] | |
```
##### CPU1 Configuration
```
| IOU0 (IIO PCIe Br1) [Auto] |Selects PCIe port |
| IOU1 (IIO PCIe Br2) [Auto] |Bifurcation for selected |
| IOU2 (IIO PCIe Br3) [Auto] |slot(s) |
|> CPU1 SLOT2 PCI-E 3.0 X16 | |
|> CPU1 SLOT4 PCI-E 3.0 X16 | |
|> CPU1 SLOT9 PCI-E 3.0 X16 | |
```
##### CPU2 Configuration
```
| IOU0 (IIO PCIe Br1) [Auto] |Selects PCIe port |
| IOU1 (IIO PCIe Br2) [Auto] |Bifurcation for selected |
| IOU2 (IIO PCIe Br3) [Auto] |slot(s) |
|> CPU2 SLOT6 PCI-E 3.0 X16 | |
|> CPU2 SLOT8 PCI-E 3.0 X16 | |
|> CPU2 SLOT10 PCI-E 3.0 X16 | |
```
#### South Bridge
```
| |Enables Legacy USB support. |
| USB Module Version 21 |AUTO option disables legacy |
| |support if no USB devices |
| USB Devices: |are connected. DISABLE |
| 1 Keyboard, 1 Mouse, 1 Hub |option will keep USB |
| |devices available only for |
| Legacy USB Support [Enabled] |EFI applications. |
| XHCI Hand-off [Enabled] | |
| Port 60/64 Emulation [Enabled] | |
| PCIe PLL SSC [Disable] | |
| Real USB Wake Up [Enabled] | |
| Front USB Wake Up [Enabled] | |
| | |
| Azalia [Auto] | |
| Azalia PME Enable [Disabled] | |
```
### PCIe/PCI/PnP Configuration
```
| PCI Bus Driver Version A5.01.18 |Enables or Disables 64bit |
| |capable Devices to be |
| PCI Devices Common Settings: |Decoded in Above 4G Address |
| Above 4G Decoding [Enabled] |Space (Only if System |
| SR-IOV Support [Enabled] |Supports 64 bit PCI |
| ARI Support [Enabled] |Decoding). |
| MMIO High Base [56T] | |
| MMIO High Granularity Size [256G] | |
| Maximum Read Request [Auto] | |
| MMCFG Base [2G] | |
| NVMe Firmware Source [Vendor Defined Fi...] | |
| VGA Priority [Onboard] | |
| CPU1 SLOT2 PCI-E 3.0 X16 OPROM [Legacy] | |
| CPU1 SLOT4 PCI-E 3.0 X16 OPROM [Legacy] | |
| CPU2 SLOT6 PCI-E 3.0 X16 OPROM [Legacy] | |
| CPU2 SLOT8 PCI-E 3.0 X16 OPROM [Legacy] | |
| CPU1 SLOT9 PCI-E 3.0 X16 OPROM [Legacy] | |
| CPU2 SLOT10 PCI-E 3.0 X16 OPROM [Legacy] | |
| CPU2 SLOT11 PCI-E 3.0 X4(IN X8) OPROM [Legacy] | |
| M.2 CONNECTOR OPROM [Legacy] | |
| Onboard LAN1 Option ROM [Legacy] | |
| Onboard LAN2 Option ROM [Disabled] | |
| Onboard Video Option ROM [Legacy] | |
|> Network Stack Configuration | |
```
### ACPI Settings
```
| ACPI Settings |Enable or Disable Non |
| |uniform Memory Access |
| NUMA [Enabled] |(NUMA). |
| WHEA Support [Enabled] | |
| High Precision Event Timer [Enabled] | |
```
## Xeon Skx Server Firmware Inventory
```
Host. IPMI IP. BMC. BIOS. CPLD. Aptio SU. CPU Microcode. PCI Bus. ME Operation FW. X710 Firmware. XXV710 Firmware. i40e.
s1-t11-sut1. 10.30.50.47. 1.39. 2.1. 03.B1.03. 2.19.1268. 0200005e. A5.01.12. 4.0.4.294. 6.01 0x800034af 1.1747.0. N/A. 2.8.20-k.
s2-t12-sut1. 10.30.50.48. 1.39. 2.0b. 03.B1.03. 2.19.1268. 0200005e. A5.01.12. 4.0.4.294. 6.01 0x800034af 1.1747.0. N/A. 2.8.20-k.
s3-t21-sut1. 10.30.50.41. 1.39. 3.2. 03.B1.03. 2.19.1268. 02000065. A5.01.18. 4.0.4.294. 6.01 0x800034af 1.1747.0. 6.02 0x80003620 1.1747.0. 2.8.20-k.
s4-t21-tg1. 10.30.50.42. 1.39. 3.2. 03.B1.03. 2.19.1268. 02000065. A5.01.18. 4.0.4.294. 6.80 0x80003cc8 1.2007.0. 6.80 0x80003d05 1.2007.0. 2.8.20-k.
s5-t22-sut1. 10.30.50.49. 1.53. 3.2. 03.B1.03. 2.19.1268. 02000065. A5.01.18. 4.0.4.294. 6.01 0x800034af 1.1747.0. 6.02 0x80003620 1.1747.0. 2.8.20-k.
s6-t22-tg1. 10.30.50.50. 1.53. 3.2. 03.B1.03. 2.19.1268. 02000065. A5.01.18. 4.0.4.294. 6.80 0x80003cc8 1.2007.0. 6.80 0x80003d05 1.2007.0. 2.8.20-k.
s7-t23-sut1. 10.30.50.51. 1.53. 3.2. 03.B1.03. 2.19.1268. 02000065. A5.01.18. 4.0.4.294. 6.01 0x800034af 1.1747.0. 6.02 0x80003620 1.1747.0. 2.8.20-k.
s8-t23-tg1. 10.30.50.52. 1.39. 3.2. 03.B1.03. 2.19.1268. 02000065. A5.01.18. 4.0.4.294. 6.80 0x80003cc8 1.2007.0. 6.80 0x80003d05 1.2007.0. 2.8.20-k.
s9-t24-sut1. 10.30.50.53. 1.39. 3.2. 03.B1.03. 2.19.1268. 02000065. A5.01.18. 4.0.4.294. 6.01 0x800034af 1.1747.0. 6.02 0x80003620 1.1747.0. 2.8.20-k.
s10-t24-tg1. 10.30.50.54. 1.39. 3.2. 03.B1.03. 2.19.1268. 02000065. A5.01.18. 4.0.4.294. 6.80 0x80003cc8 1.2007.0. 6.80 0x80003d05 1.2007.0. 2.8.20-k.
s11-t31-sut1. 10.30.50.43. 1.39. 3.2. 03.B1.03. 2.19.1268. 02000065. A5.01.18. 4.0.4.294. 6.01 0x800034af 1.1747.0. 6.02 0x80003620 1.1747.0. 2.8.20-k.
s12-t31-sut2. 10.30.50.44. 1.39. 3.2. 03.B1.03. 2.19.1268. 02000065. A5.01.18. 4.0.4.294. 6.01 0x800034af 1.1747.0. 6.02 0x80003620 1.1747.0. 2.8.20-k.
s13-t31-tg1. 10.30.50.45. 1.39. 3.2. 03.B1.03. 2.19.1268. 02000065. A5.01.18. 4.0.4.294. 6.80 0x80003cc8 1.1747.0. 6.80 0x80003d05 1.2007.0. 2.8.20-k.
s14-t32-sut1. 10.30.50.55. 1.39. 3.2. 03.B1.03. 2.19.1268. 02000065. A5.01.18. 4.0.4.294. 6.01 0x800034af 1.1747.0. 6.02 0x80003620 1.1747.0. 2.8.20-k.
s15-t32-sut2. 10.30.50.56. 1.39. 3.2. 03.B1.03. 2.19.1268. 02000065. A5.01.18. 4.0.4.294. 6.01 0x800034af 1.1747.0. 6.02 0x80003620 1.1747.0. 2.8.20-k.
s16-t32-tg1. 10.30.50.57. 1.39. 3.2. 03.B1.03. 2.19.1268. 02000065. A5.01.18. 4.0.4.294. 6.80 0x80003cc8 1.2007.0. 6.80 0x80003d05 1.2007.0. 2.8.20-k.
s19-t33t211-sut1. 10.30.50.46. 1.39. 3.2. 03.B1.03. 2.19.1268. 02000065. A5.01.18. 4.0.4.294. 6.80 0x80003cca 1.2007.0. 6.80 0x80003d05 1.2007.0. 2.8.20-k.
s28-t26t35-tg1. 10.30.55.10. 1.39. 3.2. 03.B1.03. 2.19.1268. 02000065. A5.01.18. 4.0.4.294. 6.80 0x80003cc1 1.2007.0. N/A. 2.8.20-k.
```