The NASD delay mechanism is provided to allow threads to block for specified
amounts of time. Before using it, you must initialize the
threads module. The delay mechanism provides
a delay type nasd_delaycounter_t. To introduce a delay of
a number of microseconds:
NASD_BEGIN_DELAYCNT() and the NASD_DELAY_FROM()
calls. NASD_DELAY_FROM() will ensure that at least
usec_delay microseconds have elapsed after
NASD_BEGIN_DELAYCNT() and before NASD_DELAY_FROM()
completes. One place where this is used is in the drive read-throttling code.
The inner transmit loop ensures that each transfer consumes a minimum amount
of time, thus bounding the resulting bandwidth.
| Timing | Timeouts | NASD Programmer's Documentation |