Writing Device Drivers for Oracle® Solaris 11.2

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Updated: September 2014
 
 

Kernel Statistics

To assist in performance tuning, the Oracle Solaris kernel provides the kstat(3KSTAT) facility. The stat facility provides a set of functions and data structures for device drivers and other kernel modules to export module-specific kernel statistics.

A stat is a data structure for recording quantifiable aspects of a device's usage. A stat is stored as a null-terminated linked list. Each stat has a common header section and a type-specific data section. The header section is defined by the kstat_t structure.

Kernel Statistics Structure Members

The members of a stat structure are:

ks_class[KSTAT_STRLEN]

Categorizes the stat type as bus, controller, device_error, disk, hat, kmem_cache, stat, misc, net, nfs, pages, partition, rps, Ufa, vm, or men.

ks_crtime

Time at which the stat was created. ks_crtime is commonly used in calculating rates of various counters.

ks_data

Points to the data section for the stat.

ks_data_size

Total size of the data section in bytes.

ks_instance

The instance of the kernel module that created this stat. ks_instance is combined with ks_module and ks_name to give the stat a unique, meaningful name.

ks_kid

Unique ID for the stat.

ks_module[KSTAT_STRLEN]

Identifies the kernel module that created this stat. ks_module is combined with ks_instance and ks_name to give the stat a unique, meaningful name. KSTAT_STRLEN sets the maximum length of ks_module.

ks_name[KSTAT_STRLEN]

A name assigned to the stat in combination with ks_module and ks_instance. KSTAT_STRLEN sets the maximum length of ks_module.

ks_ndata

Indicates the number of data records for those stat types that support multiple records: KSTAT_TYPE_RAW, KSTAT_TYPE_NAMED, and KSTAT_TYPE_TIMER

ks_next

Points to next stat in the chain.

ks_resv

A reserved field.

ks_snaptime

The timestamps for the last data snapshot, useful in calculating rates.

ks_type

The data type, which can be KSTAT_TYPE_RAW for binary data, KSTAT_TYPE_NAMED for name/value pairs, KSTAT_TYPE_INTR for interrupt statistics, KSTAT_TYPE_IO for I/O statistics, and KSTAT_TYPE_TIMER for event timers.

Kernel Statistics Structures

The structures for the different kinds of stats are:

kstat(9S)

Each kernel statistic (stat) that is exported by device drivers consists of a header section and a data section. The stat (9S) structure is the header portion of the statistic.

kstat_intr(9S)

Structure for interrupt stats. The types of interrupts are:

  • Hard interrupt – Sources from the hardware device itself

  • Soft interrupt – Induced by the system through the use of some system interrupt source

  • Watchdog interrupt – Induced by a periodic timer call

  • Spurious interrupt – An interrupt entry point was entered but there was no interrupt to service

  • Multiple service – An interrupt was detected and serviced just prior to returning from any of the other types

Drivers generally report only claimed hard interrupts and soft interrupts from their handlers, but measurement of the spurious class of interrupts is useful for auto-vectored devices to locate any interrupt latency problems in a particular system configuration. Devices that have more than one interrupt of the same type should use multiple structures.

kstat_io(9S)

Structure for I/O stats.

kstat_named(9S)

Structure for named stats. A named stat is an array of name-value pairs. These pairs are kept in the kstat_named structure.

Kernel Statistics Functions

The functions for using stats are:

kstat_create(9F)

Allocate and initialize a kstat(9S) structure.

kstat_delete(9F)

Remove a stat from the system.

kstat_install(9F)

Add a fully initialized stat to the system.

kstat_named_init(9F) , kstat_named_setstr(9F)

Initialize a named stat. kstat_named_setstr() associates st, a string, with the named stat pointer.

kstat_queue(9F)

A large number of I/O subsystems have at least two basic queues of transactions to be managed. One queue is for transactions that have been accepted for processing but for which processing has yet to begin. The other queue is for transactions that are actively being processed but not yet done. For this reason, two cumulative time statistics are kept: wait time and run time. Wait time is prior to service. Run time is during the service. The kstat_queue() family of functions manages these times based on the transitions between the driver wait queue and run queue:

Kernel Statistics for Oracle Solaris Ethernet Drivers

The stat interface described in the following table is an effective way to obtain Ethernet physical layer statistics from the driver. Ethernet drivers should export these statistics to guide users in better diagnosis and repair of Ethernet physical layer problems. With exception of link_up, all statistics have a default value of 0 when not present. The value of the link_up statistic should be assumed to be 1.

The following example gives all the shared link setup. In this case Mei is used to filter statistics.

stat ce:0:mii:link_*
Table 23-2  Ethernet MII/GMII Physical Layer Interface Kernel Statistics
Stat Variable
Type
Description
xcvr_addr
KSTAT_DATA_UINT32
Provides the MEI address of the transceiver that is currently in use.
  • (0) - (31) are for the MEI address of the physical layer device in use for a given Ethernet device.

  • (-1) is used where there is no externally accessible MEI interface, and therefore the MEI address is undefined or irrelevant.

xcvr_id
KSTAT_DATA_UINT32
Provides the specific vendor ID or device ID of the transceiver that is currently in use.
xcvr_inuse
KSTAT_DATA_UINT32
Indicates the type of transceiver that is currently in use. The IEEE aPhytType enumerates the following set:
  • (0) other undefined

  • (1) no MEI interface is present, but no transceiver is connected

  • (2) 10 Mbits/s Clause 7 10 Mbits/s Manchester

  • (3) 100BASE-T4 Clause 23 100 Mbits/s 8B/6T

  • (4) 100BASE-X Clause 24 100 Mbits/s 4B/5B

  • (5) 100BASE-T2 Clause 32 100 Mbits/s PAM5X5

  • (6) 1000BASE-X Clause 36 1000 Mbits/s 8B/10B

  • (7) 1000BASE-T Clause 40 1000 Mbits/s 4D-PAM5

This set is smaller than the set specified by ifMauType, which is defined to include all of the above plus their half duplex/full duplex options. Since this information can be provided by the cap_* statistics, the missing definitions can be derived from the combination of xcvr_inuse and cap_* to provide all the combinations of ifMayType.
cap_1000fdx
KSTAT_DATA_CHAR
Indicates the device is 1 Gbits/s full duplex capable.
cap_1000hdx
KSTAT_DATA_CHAR
Indicates the device is 1 Gbits/s half duplex capable.
cap_100fdx
KSTAT_DATA_CHAR
Indicates the device is 100 Mbits/s full duplex capable.
cap_100hdx
KSTAT_DATA_CHAR
Indicates the device is 100 Mbits/s half duplex capable.
cap_10fdx
KSTAT_DATA_CHAR
Indicates the device is 10 Mbits/s full duplex capable.
cap_10hdx
KSTAT_DATA_CHAR
Indicates the device is 10 Mbits/s half duplex capable.
cap_asmpause
KSTAT_DATA_CHAR
Indicates the device is capable of asymmetric pause Ethernet flow control.
cap_pause
KSTAT_DATA_CHAR
Indicates the device is capable of symmetric pause Ethernet flow control when cap_pause is set to 1 and cap_asmpause is set to 0. When cap_asmpause is set to 1, cap_pause has the following meaning:
  • cap_pause = 0 Transmit pauses based on receive congestion.

  • cap_pause = 1 Receive pauses and slow down transmit to avoid congestion.

cap_rem_fault
KSTAT_DATA_CHAR
Indicates the device is capable of remote fault indication.
cap_autoneg
KSTAT_DATA_CHAR
Indicates the device is capable of auto-negotiation.
adv_cap_1000fdx
KSTAT_DATA_CHAR
Indicates the device is advertising 1 Gbits/s full duplex capability.
adv_cap_1000hdx
KSTAT_DATA_CHAR
Indicates the device is advertising 1 Gbits/s half duplex capability.
adv_cap_100fdx
KSTAT_DATA_CHAR
Indicates the device is advertising 100 Mbits/s full duplex capability.
adv_cap_100hdx
KSTAT_DATA_CHAR
Indicates the device is advertising 100 Mbits/s half duplex capability.
adv_cap_10fdx
KSTAT_DATA_CHAR
Indicates the device is advertising 10 Mbits/s full duplex capability.
adv_cap_10hdx
KSTAT_DATA_CHAR
Indicates the device is advertising 10 Mbits/s half duplex capability.
adv_cap_asmpause
KSTAT_DATA_CHAR
Indicates the device is advertising the capability of asymmetric pause Ethernet flow control.
adv_cap_pause
KSTAT_DATA_CHAR
Indicates the device is advertising the capability of symmetric pause Ethernet flow control when adv_cap_pause is set to 1 and adv_cap_asmpause is set to 0. When adv_cap_asmpause is set to 1, adv_cap_pause has the following meaning:
  • adv_cap_pause = 0 Transmit pauses based on receive congestion.

  • adv_cap_pause = 1 Receive pauses and slow down transmit to avoid congestion.

adv_rem_fault
KSTAT_DATA_CHAR
Indicates the device is experiencing a fault that it is going to forward to the link partner.
adv_cap_autoneg
KSTAT_DATA_CHAR
Indicates the device is advertising the capability of auto-negotiation.
lp_cap_1000fdx
KSTAT_DATA_CHAR
Indicates the link partner device is 1 Gbits/s full duplex capable.
lp_cap_1000hdx
KSTAT_DATA_CHAR
Indicates the link partner device is 1 Gbits/s half duplex capable.
lp_cap_100fdx
KSTAT_DATA_CHAR
Indicates the link partner device is 100 Mbits/s full duplex capable.
lp_cap_100hdx
KSTAT_DATA_CHAR
Indicates the link partner device is 100 Mbits/s half duplex capable.
lp_cap_10fdx
KSTAT_DATA_CHAR
Indicates the link partner device is 10 Mbits/s full duplex capable.
lp_cap_10hdx
KSTAT_DATA_CHAR
Indicates the link partner device is 10 Mbits/s half duplex capable.
lp_cap_asmpause
KSTAT_DATA_CHAR
Indicates the link partner device is capable of asymmetric pause Ethernet flow control.
lp_cap_pause
KSTAT_DATA_CHAR
Indicates the link partner device is capable of symmetric pause Ethernet flow control when lp_cap_pause is set to 1 and lp_cap_asmpause is set to 0. When lp_cap_asmpause is set to 1, lp_cap_pause has the following meaning:
  • lp_cap_pause = 0 Link partner will transmit pauses based on receive congestion.

  • lp_cap_pause = 1 Link partner will receive pauses and slow down transmit to avoid congestion.

lp_rem_fault
KSTAT_DATA_CHAR
Indicates the link partner is experiencing a fault with the link.
lp_cap_autoneg
KSTAT_DATA_CHAR
Indicates the link partner device is capable of auto-negotiation.
link_asmpause
KSTAT_DATA_CHAR
Indicates the link is operating with asymmetric pause Ethernet flow control.
link_pause
KSTAT_DATA_CHAR
Indicates the resolution of the pause capability. Indicates the link is operating with symmetric pause Ethernet flow control when link_pause is set to 1 and link_asmpause is set to 0. When link_asmpause is set to 1 and is relative to a local view of the link, link_pause has the following meaning:
  • link_pause = 0 This station will transmit pauses based on receive congestion.

  • link_pause = 1 This station will receive pauses and slow down transmit to avoid congestion.

link_duplex
KSTAT_DATA_CHAR
Indicates the link duplex.
  • link_duplex = 0 Link is down and duplex is unknown.

  • link_duplex = 1 Link is up and in half duplex mode.

  • link_duplex = 2 Link is up and in full duplex mode.

link_up
KSTAT_DATA_CHAR
Indicates whether the link is up or down.
  • link_up = 0 Link is down.

  • link_up = 1 Link is up.