Script enables monitoring of the TUR commands, their latency and errors returned from the calls.

sd-test-unit-ready.d

#!/usr/sbin/dtrace -Cs
#pragma D option quiet

#define SD_TO_DEVINFO(un) ((struct dev_info *)((un)->un_sd->sd_dev))
#define DEV_NAME(un) \
      stringof(`devnamesp[SD_TO_DEVINFO(un)->devi_major].dn_name) /* ` */
#define DEV_INST(un) (SD_TO_DEVINFO(un)->devi_instance)
 
::sd_send_scsi_TEST_UNIT_READY:entry {
    self->un = args[0]->ssc_un;
    self->start = timestamp;
}

::sd_send_scsi_TEST_UNIT_READY:return /self->un/ {
    @ts[DEV_INST(self->un)] = quantize(timestamp - self->start);
    @[DEV_INST(self->un), args[1]] = count();
}

tick-5sec {
    printa("device=sd%d err=%d %@d\n", @);
    trunc(@);
}