Annotation of wikisrc/tutorials/how_to_enable_and_run_dtrace.mdwn, revision 1.16
1.15 sevan 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://dtrace.org) for more information.
2: Also see [DTrace Introduction](http://dtrace.org/guide/preface.html), Brendan Gregg's [DTrace one liners](http://www.brendangregg.com/DTrace/dtrace_oneliners.txt) and his notes for [DTrace on FreeBSD](https://wiki.freebsd.org/DTrace/).
1.2 schmonz 3:
1.5 wiki 4: # Current status
1.2 schmonz 5:
1.5 wiki 6: ## Supported platforms
7:
8: DTrace is a work-in-progress effort and it is for x86 systems and some arm boards.
9:
10: * i386 and amd64
1.14 sevan 11: * earm* (evbarm and armv4 based ports (armv4 side requires further testing but system is built with CTF)
1.5 wiki 12:
13: ## Supported providers
14:
15: * SDT: Statically Defined Tracing
16: * FBT: Function Boundary Tracing
1.14 sevan 17: * Lockstat: Kernel Lock Statistics
18: * Profile: Time based interrupt event source for Profiling
19: * Syscall: System Calls
20: * Syscall Linux (32bit & 64 bit): System calls via the Linux binary emulation layer
1.2 schmonz 21:
1.6 riastrad 22: ## TODO for netbsd-7
23:
24: * Measure effect of `options KDTRACE_HOOKS` on system performance.
25: * Determine whether the profile module works and list it here.
1.7 riastrad 26: * Integrate [[riz|users/riz]]'s syscall provider patch.
1.6 riastrad 27:
28: ## TODO for netbsd-6
29:
30: Need to identify changes to pull up to netbsd-6 and pull them up.
31: Candidates:
32:
33: * Profile provider.
34:
1.5 wiki 35: # How to use
36:
1.2 schmonz 37: ## Building DTrace
38:
39: You need the following options in your kernel:
40:
1.10 wiz 41: options KDTRACE_HOOKS # kernel DTrace hooks
1.2 schmonz 42: options MODULAR
43:
1.14 sevan 44: Optionally:
1.16 ! sevan 45:
1.14 sevan 46: options INSECURE # permit modules to loaded from user space once system has gone multiuser and securelevel has been raised.
1.2 schmonz 47:
1.14 sevan 48: A Distribution needs to be built with the options `MKDTRACE=yes` and `MKCTF=yes`, this is taken care of automatically and doesn't need to be specified manually. The list of platforms it is applied to automatically is set in `src/share/mk/bsd.own.mk`
1.2 schmonz 49:
1.14 sevan 50: Set the system to load the solaris and dtrace related modules in `/etc/modules.conf`, for a list of available modules, see `/stand/$MACHINE/$VERSION/modules/`
1.2 schmonz 51:
1.14 sevan 52: solaris
53: dtrace
54: dtrace_sdt
55: dtrace_fbt
56: dtrace_lockstat
57: dtrace_profile
58: dtrace_syscall
1.2 schmonz 59:
1.14 sevan 60: A `dtrace` device node is created automatically in `/dev/dtrace` when the modules are loaded into place.
1.2 schmonz 61:
62: List the dtrace probes
63:
64: dtrace -l
65:
66: ID PROVIDER MODULE FUNCTION NAME
67: 1 dtrace BEGIN
68: 2 dtrace END
69: 3 dtrace ERROR
70: 4 fbt netbsd AcpiAcquireGlobalLock entry
71: 5 fbt netbsd AcpiAcquireGlobalLock return
72: 6 fbt netbsd AcpiAllocateRootTable entry
73: 7 fbt netbsd AcpiAttachData entry
74: .
75: .
76: 29129 fbt solaris zfs_vop_getattr entry
77: 29130 fbt solaris zfs_vop_getattr return
78: 29131 proc create
79: 29132 proc exec
80: .
81: .
82: 29140 proc lwp_start
83: 29141 proc lwp_exit
84:
85:
1.14 sevan 86: ## Running hello world
1.2 schmonz 87:
1.9 wiz 88: Put the following into the file hello.d:
1.2 schmonz 89:
90: BEGIN
91: {
92: trace("Hello world");
93: exit(0);
94: }
95:
96:
97: Run the hello world script:
98:
99: dtrace -s hello.d
100:
101: dtrace: script './hello.d' matched 1 probe
102: CPU ID FUNCTION:NAME
103: 0 1 :BEGIN Hello world
104:
105:
1.9 wiz 106: A more complex example that traces the execution of a sleep operation
107: in the kernel. Put it in sleep.d:
1.2 schmonz 108:
109: #pragma D option flowindent
110:
111: fbt::syscall:entry
112: /execname == "sleep" && guard++ == 0/
113: {
114: self->traceme = 1;
115: printf("fd: %d", arg0);
116: }
117:
1.9 wiz 118: fbt::syscall:entry /self->traceme/ {}
1.2 schmonz 119:
120: fbt::syscall:return
121: /self->traceme/
122: {
123: self->traceme = 0;
124: exit(0);
125: }
126:
127:
1.9 wiz 128: Start the script running (dtrace -s sleep.d) and then execute a "sleep 2" in another shell.
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