kstat_io(9S)

NAME

     kstat_io - structure for I/O kstats

SYNOPSIS

     #include <sys/types.h>
     #include <sys/kstat.h>
     #include <sys/ddi.h>
     #include <sys/sunddi.h>

INTERFACE LEVEL

     Solaris DDI specific (Solaris DDI)

DESCRIPTION

     I/O kstat statistics are kept in a kstat_io structure.  When
     kstat_create(9F)  creates an I/O kstat, the ks_data field is
     a  pointer  to  one   of   these   structures.   The   macro
     KSTAT_IO_PTR()  is provided to retrieve this field. It looks
     like this:

     #define KSTAT_IO_PTR(kptr)    ((kstat_io_t *)(kptr)->ks_data)

STRUCTURE MEMBERS

     u_longlong_t      nread;      /* number of bytes read */
     u_longlong_t      nwritten;   /* number of bytes written *]/
     ulong_t           reads;      /* number of read operations */
     ulong_t           writes;     /* number of write operations */

     The nread field should be updated by  the  driver  with  the
     number of bytes successfully read upon completion.

     The nwritten field should be updated by the driver with  the
     number of bytes successfully written upon completion.

     The reads field should be updated by the driver  after  each
     successful read operation.

     The writes field should be updated by the driver after  each
     successful write operation

     Other I/O statistics are updated  through  the  use  of  the
     kstat_queue(9F) functions.

SEE ALSO

     kstat_create(9F),   kstat_named_init(9F),   kstat_queue(9F),
     kstat_runq_back_to_waitq(9F),          kstat_runq_enter(9F),
     kstat_runq_exit(9F),                  kstat_waitq_enter(9F),
     kstat_waitq_exit(9F), kstat_waitq_to_runq(9F)

     Writing Device Drivers