drv_hztousec(9F) Kernel Functions for Drivers drv_hztousec(9F)NAMEdrv_hztousec - convert clock ticks to microseconds
SYNOPSIS
#include <sys/types.h>
#include <sys/ddi.h>
clock_t drv_hztousec(clock_t hertz);
INTERFACE LEVEL
Architecture independent level 1 (DDI/DKI).
PARAMETERS
hertz The number of clock ticks to convert.
DESCRIPTION
The drv_hztousec() function converts into microseconds the time
expressed by hertz, which is in system clock ticks.
The length of time the system has been up since boot can be retrieved
by calling ddi_get_lbolt(9F), which will return a value of type clock_t
containing the number of clock ticks since boot. Drivers often use the
value of lbolt before and after an I/O request to measure the amount of
time it took the device to process the request. The drv_hztousec()
function can be used by the driver to convert the reading from clock
ticks to a known unit of time.
RETURN VALUES
The number of microseconds equivalent to the hertz parameter. No error
value is returned. If the microsecond equivalent to hertz is too large
to be represented as a clock_t, then the maximum clock_t value will be
returned.
CONTEXT
The drv_hztousec() function can be called from user, interrupt, or ker‐
nel context.
SEE ALSOddi_get_lbolt(9F), drv_usectohz(9F), drv_usecwait(9F)
Writing Device Drivers
SunOS 5.11 4 Sep 2009 drv_hztousec(9F)
