kstat_runq_enter man page on OpenIndiana

Man page or keyword search:  
man Server   20441 pages
apropos Keyword Search (all sections)
Output format
OpenIndiana logo
[printable version]

kstat_queue(9F)		 Kernel Functions for Drivers	       kstat_queue(9F)

NAME
       kstat_queue,   kstat_waitq_enter,  kstat_waitq_exit,  kstat_runq_enter,
       kstat_runq_exit, kstat_waitq_to_runq, kstat_runq_back_to_waitq - update
       I/O kstat statistics

SYNOPSIS
       #include <sys/types.h>
       #include <sys/kstat.h>

       void kstat_waitq_enter(kstat_io_t *kiop);

       void kstat_waitq_exit(kstat_io_t *kiop);

       void kstat_runq_enter(kstat_io_t *kiop);

       void kstat_runq_exit(kstat_io_t *kiop);

       void kstat_waitq_to_runq(kstat_io_t *kiop);

       void kstat_runq_back_to_waitq(kstat_io_t *kiop);

INTERFACE LEVEL
       Solaris DDI specific (Solaris DDI)

PARAMETERS
       kiop	Pointer to a kstat_io(9S) structure.

DESCRIPTION
       A  large	 number	 of I/O subsystems have at least two basic "lists" (or
       queues) of transactions they manage: one	 for  transactions  that  have
       been accepted for processing but for which processing has yet to begin,
       and one for transactions which are actively being  processed  (but  not
       done).  For  this reason, two cumulative time statistics are kept: wait
       (pre-service) time, and run (service) time.

       The kstat_queue() family of functions manage these times based  on  the
       transitions between the driver wait queue and run queue.

       kstat_waitq_enter()	     kstat_waitq_enter() should be called when
				     a request arrives and is  placed  into  a
				     pre-service  state (such as just prior to
				     calling disksort(9F)).

       kstat_waitq_exit()	     kstat_waitq_exit() should be used when  a
				     request  is  removed from its pre-service
				     state. (such as just prior to calling the
				     driver's start routine).

       kstat_runq_enter()	     kstat_runq_enter()	 is also called when a
				     request is placed in  its	service	 state
				     (just prior to calling the driver's start
				     routine, but after kstat_waitq_exit()).

       kstat_runq_exit()	     kstat_runq_exit() is used when a  request
				     is	 removed  from its service state (just
				     prior to calling biodone(9F)).

       kstat_waitq_to_runq()	     kstat_waitq_to_runq()    transitions    a
				     request  from  the	 wait queue to the run
				     queue. This is useful wherever the driver
				     would     have	normally     done    a
				     kstat_waitq_exit() followed by a call  to
				     kstat_runq_enter().

       kstat_runq_back_to_waitq()    kstat_runq_back_to_waitq()	 transitions a
				     request from the run queue	 back  to  the
				     wait queue. This may be necessary in some
				     cases (write throttling is an example).

RETURN VALUES
       None.

CONTEXT
       kstat_create() can be called from user or kernel context.

WARNINGS
       These transitions must be protected by holding the kstat's ks_lock, and
       must  be completely accurate (all transitions are recorded). Forgetting
       a transition may, for example, make an idle disk appear 100% busy.

SEE ALSO
       biodone(9F),    disksort(9F),	kstat_create(9F),    kstat_delete(9F),
       kstat_named_init(9F), kstat(9S), kstat_io(9S)

       Writing Device Drivers

SunOS 5.11			  4 Apr 1994		       kstat_queue(9F)
[top]

List of man pages available for OpenIndiana

Copyright (c) for man pages and the logo by the respective OS vendor.

For those who want to learn more, the polarhome community provides shell access and support.

[legal] [privacy] [GNU] [policy] [cookies] [netiquette] [sponsors] [FAQ]
Tweet
Polarhome, production since 1999.
Member of Polarhome portal.
Based on Fawad Halim's script.
....................................................................
Vote for polarhome
Free Shell Accounts :: the biggest list on the net