Probes
The io probes are described in Table 27-1.
Table 27-1 io Probes
Probe |
Description |
|---|
start |
Probe that fires when an I/O
request is about to be made either to a peripheral device or to
an NFS server. The bufinfo_t corresponding to the I/O request is pointed to
by args[0]. The devinfo_t of the device to which the I/O is
being issued is pointed to by args[1]. The fileinfo_t of the file
that corresponds to the I/O request is pointed to by args[2]. Note that file
information availability depends on the filesystem making the I/O request. See fileinfo_t for
more information. |
done |
Probe that fires after an I/O request has been fulfilled. The
bufinfo_t corresponding to the I/O request is pointed to by args[0]. The done
probe fires after the I/O completes, but before completion processing has been performed
on the buffer. As a result B_DONE is not set in b_flags
at the time the done probe fires. The devinfo_t of the device to which
the I/O was issued is pointed to by args[1]. The fileinfo_t of the
file that corresponds to the I/O request is pointed to by args[2]. |
wait-start |
Probe that
fires immediately before a thread begins to wait pending completion of a given
I/O request. The buf(9S) structure corresponding to the I/O request for which the
thread will wait is pointed to by args[0]. The devinfo_t of the
device to which the I/O was issued is pointed to by args[1].
The fileinfo_t of the file that corresponds to the I/O request is pointed
to by args[2]. Some time after the wait-start probe fires, the wait-done probe will
fire in the same thread. |
wait-done |
Probe that fires when a thread is done
waiting for the completion of a given I/O request. The bufinfo_t corresponding to
the I/O request for which the thread will wait is pointed to by
args[0]. The devinfo_t of the device to which the I/O was issued is pointed
to by args[1]. The fileinfo_t of the file that corresponds to the I/O
request is pointed to by args[2]. The wait-done probe fires only after the
wait-start probe has fired in the same thread. |
Note that the io probes fire for all I/O requests to peripheral devices,
and for all file read and file write requests to an NFS server.
Requests for metadata from an NFS server, for example, do not trigger
io probes due to a readdir(3C) request.
