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32 .Nd a DTrace provider for tracing events related to disk I/O
34 .Fn io:::start "struct bio *" "struct devstat *"
35 .Fn io:::done "struct bio *" "struct devstat *"
39 provider allows the tracing of disk I/O events.
42 probe fires when a I/O request is about to be sent to the backing driver of a
47 transformations have been performed on the request.
50 probe fires when a I/O request is completed.
53 representing the I/O request as their first argument.
54 The second argument is a
55 .Vt "struct devstat *"
64 manual page, and the fields of
73 D types are defined in
74 .Pa /usr/lib/dtrace/io.d .
76 .Bl -tag -width "/usr/lib/dtrace/io.d" -compact
77 .It Pa /usr/lib/dtrace/io.d
78 DTrace type and translator definitions for the
83 The following script shows a per-process breakdown of total I/O by disk device:
84 .Bd -literal -offset indent
85 #pragma D option quiet
89 @[args[1]->device_name, execname, pid] = sum(args[0]->bio_bcount);
94 printf("%10s %20s %10s %15s\\n", "DEVICE", "APP", "PID", "BYTES");
95 printa("%10s %20s %10d %15@d\\n", @);
99 This provider is not compatible with the
101 provider found in Solaris, as its probes use native
111 provider first appeared in
115 This manual page was written by
116 .An Mark Johnston Aq Mt markj@FreeBSD.org .
122 probes are not currently implemented on