File:  [NetBSD Developer Wiki] / wikisrc / tutorials / how_to_enable_and_run_dtrace.mdwn
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Wed Jul 3 23:14:31 2013 UTC (7 years, 2 months ago) by wiki
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    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: 
    4: DTrace is a work-in-progress effort and it is for x86 systems only currently (there is some arm support but it is completely untested). Two providers are available; the Statically Defined Tracing (SDT) provider and the Function Boundary Tracer (FBT) provider. 
    5: 
    6: You can currently run a hello world DScript. 
    7: 
    8: ##  Building DTrace 
    9: 
   10: You need the following options in your kernel: 
   11:     
   12:     options         INSECURE
   13:     options         KDTRACE_HOOKS   # DTrace support
   14:     options         MODULAR
   15:     
   16: 
   17: You also need to build distribution with the options MKMODULAR=yes and MKDTRACE=yes. 
   18: 
   19: ##  Running hello world 
   20: 
   21: Load the solaris and dtrace modules, and the SDT (Statically Defined Tracing) and FBT (Function Boundary Tracing) modules: 
   22:     
   23:     modload solaris
   24:     modload dtrace
   25:     modload sdt
   26:     modload fbt
   27:     
   28: 
   29: Make the dtrace device node: 
   30:     
   31:     mkdir /dev/dtrace
   32:     mknod /dev/dtrace/dtrace c dtrace 0
   33:     
   34: 
   35: List the dtrace probes 
   36:     
   37:     dtrace -l
   38:     
   39:        ID   PROVIDER            MODULE                          FUNCTION NAME
   40:         1     dtrace                                                     BEGIN
   41:         2     dtrace                                                     END
   42:         3     dtrace                                                     ERROR
   43:         4        fbt            netbsd             AcpiAcquireGlobalLock entry
   44:         5        fbt            netbsd             AcpiAcquireGlobalLock return
   45:         6        fbt            netbsd             AcpiAllocateRootTable entry
   46:         7        fbt            netbsd                    AcpiAttachData entry
   47:         . 
   48:         .
   49:     29129        fbt           solaris                   zfs_vop_getattr entry 
   50:     29130        fbt           solaris                   zfs_vop_getattr return
   51:     29131       proc                                                     create
   52:     29132       proc                                                     exec 
   53:         .
   54:         .
   55:     29140       proc                                                     lwp_start
   56:     29141       proc                                                     lwp_exit
   57:     
   58: 
   59:   
   60: 
   61: 
   62: Put the following into the file hello.d 
   63:     
   64:     BEGIN
   65:     {
   66:         trace("Hello world");
   67:         exit(0);
   68:     }
   69:     
   70: 
   71: Run the hello world script: 
   72:     
   73:     dtrace -s hello.d
   74:     
   75:     dtrace: script './hello.d' matched 1 probe
   76:     CPU     ID                    FUNCTION:NAME
   77:       0      1                           :BEGIN   Hello world
   78:     
   79: 
   80: A more complex example that traces the execution of a sleep operation in the kernel: 
   81:     
   82:     #pragma D option flowindent
   83:     
   84:     fbt::syscall:entry
   85:     /execname == "sleep" && guard++ == 0/
   86:     {
   87:             self->traceme = 1;
   88:             printf("fd: %d", arg0);
   89:     }
   90:     
   91:     fbt:::
   92:     /self->traceme/
   93:     {}
   94:     
   95:     fbt::syscall:return
   96:     /self->traceme/
   97:     {
   98:             self->traceme = 0;
   99:             exit(0);
  100:     }
  101:     
  102: 
  103: Start the script running (dtrace -s <scriptname.d>) and then execute a sleep 2 in another shell. 
  104: 

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