Annotation of wikisrc/how_to_enable_and_run_dtrace.mdwn, revision 1.1

1.1     ! wiki        1: DTrace is a Dynamic Tracing framework developed by Sun and ported to NetBSD. It enables extensive instrumentation of the kernel and user space. See the [DTrace Community Page](http://hub.opensolaris.org/bin/view/Community+Group+dtrace/WebHome) for more information. Also see [DTrace Introduction](http://wikis.sun.com/display/DTrace/Introduction).
        !             2: 
        !             3: DTrace is a work-in-progress effort and it is for i386 systems only. Two providers are available; the Statically Defined Tracing (SDT) provider and the Function Boundary Tracer (FBT) provider.
        !             4: 
        !             5: ##Building DTrace
        !             6: 
        !             7: You need the following options in your kernel:
        !             8: 
        !             9:     options         INSECURE
        !            10:     options         KDTRACE_HOOKS   # DTrace support
        !            11:     options         MODULAR
        !            12: 
        !            13: Note: Make sure "options DEBUG" is not defined. There is currently a problem where the debug symbols overwrite the CTF symbols.  Its not fatal, but your DTrace scripts will not recognize any symbols in the kernel rendering them unusable.
        !            14: 
        !            15: You also need to build distribution with the options MKMODULAR=yes and MKDTRACE=yes.
        !            16: 
        !            17: ##Running hello world
        !            18: 
        !            19: Load the solaris and dtrace modules, and the SDT (Statically Defined Tracing) and FBT (Function Boundary Tracing) modules:
        !            20: 
        !            21:     modload solaris
        !            22:     modload dtrace
        !            23:     modload sdt
        !            24:     modload fbt
        !            25: 
        !            26: Make the dtrace device node:
        !            27: 
        !            28:     mkdir /dev/dtrace
        !            29:     mknod /dev/dtrace/dtrace c dtrace 0
        !            30: 
        !            31: List the dtrace probes
        !            32: 
        !            33:     dtrace -l
        !            34: 
        !            35:        ID   PROVIDER            MODULE                          FUNCTION NAME
        !            36:         1     dtrace                                                     BEGIN
        !            37:         2     dtrace                                                     END
        !            38:         3     dtrace                                                     ERROR
        !            39:         4        fbt            netbsd             AcpiAcquireGlobalLock entry
        !            40:         5        fbt            netbsd             AcpiAcquireGlobalLock return
        !            41:         6        fbt            netbsd             AcpiAllocateRootTable entry
        !            42:         7        fbt            netbsd                    AcpiAttachData entry
        !            43:         . 
        !            44:         .
        !            45:     29129        fbt           solaris                   zfs_vop_getattr entry 
        !            46:     29130        fbt           solaris                   zfs_vop_getattr return
        !            47:     29131       proc                                                     create
        !            48:     29132       proc                                                     exec 
        !            49:         .
        !            50:         .
        !            51:     29140       proc                                                     lwp_start
        !            52:     29141       proc                                                     lwp_exit
        !            53: 
        !            54: Put the following into the file hello.d
        !            55: 
        !            56:     BEGIN
        !            57:     {
        !            58:         trace("Hello world");
        !            59:         exit(0);
        !            60:     }
        !            61: 
        !            62: Run the hello world script:
        !            63: 
        !            64:     dtrace -s hello.d
        !            65:     
        !            66:     dtrace: script './hello.d' matched 1 probe
        !            67:     CPU     ID                    FUNCTION:NAME
        !            68:       0      1                           :BEGIN   Hello world
        !            69: 
        !            70: A more complex example that traces the execution of a sleep operation in the kernel:
        !            71: 
        !            72:     #pragma D option flowindent
        !            73:     
        !            74:     fbt::syscall:entry
        !            75:     /execname == "sleep" && guard++ == 0/
        !            76:     {
        !            77:             self->traceme = 1;
        !            78:             printf("fd: %d", arg0);
        !            79:     }
        !            80:     
        !            81:     fbt:::
        !            82:     /self->traceme/
        !            83:     {}
        !            84: 
        !            85:     fbt::syscall:return
        !            86:     /self->traceme/
        !            87:     {
        !            88:             self->traceme = 0;
        !            89:             exit(0);
        !            90:     }
        !            91: 
        !            92: Start the script running (dtrace -s scriptname.d) and then execute a sleep 2 in another shell.

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