Solaris Dynamic Tracing Guide
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Document Information

Preface

1.  Introduction

2.  Types, Operators, and Expressions

3.  Variables

4.  D Program Structure

5.  Pointers and Arrays

6.  Strings

7.  Structs and Unions

8.  Type and Constant Definitions

9.  Aggregations

10.  Actions and Subroutines

11.  Buffers and Buffering

12.  Output Formatting

13.  Speculative Tracing

14.  dtrace(1M) Utility

15.  Scripting

16.  Options and Tunables

17.  dtrace Provider

18.  lockstat Provider

19.  profile Provider

20.  fbt Provider

21.  syscall Provider

22.  sdt Provider

23.  sysinfo Provider

24.  vminfo Provider

25.  proc Provider

26.  sched Provider

27.  io Provider

Probes

Arguments

Examples

Stability

28.  mib Provider

29.  fpuinfo Provider

30.  pid Provider

31.  plockstat Provider

32.  fasttrap Provider

33.  User Process Tracing

34.  Statically Defined Tracing for User Applications

35.  Security

36.  Anonymous Tracing

37.  Postmortem Tracing

38.  Performance Considerations

39.  Stability

40.  Translators

41.  Versioning

Glossary

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.
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