Date: Thu, 25 May 2006 06:55:10 +0000 From: John Birrell <jb@what-creek.com> To: current@freebsd.org Subject: DTrace for FreeBSD - Status Update Message-ID: <20060525065510.GA20475@what-creek.com>
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It's nearly 8 weeks since I started porting DTrace to FreeBSD and I thought I would post a status update including today's significant emotional event. 8-) For those who don't know what DTrace is or which company designed it, here are a few links: The BigAdmin: <http://www.sun.com/bigadmin/content/dtrace/>; A Blurb: <http://www.sun.com/2004-0518/feature/index.html>; The Guide: <http://docs.sun.com/app/docs/doc/817-6223>; My FreeBSD Project Page: <http://people.freebsd.org/~jb/dtrace/index.html>; Much of the basic DTrace infrastructure is in place now. Of the 1039 DTrace tests that Sun runs on Solaris, 793 now pass on FreeBSD. We've got the following providers: - dtrace - profile - syscall - sdt - fbt As of today, loading those providers on a GENERIC kernel gives 32,519 probes. Today's significant emotional event added over 30,000 of those, thanks to the Function Boundary Tracing (fbt) provider. It provides the instrumentation of the entry and return of every (non-leaf) function in the kernel and (non-DTrace provider) modules. Here is an example of what fbt can do.... The following script creates a probe on the entry to the kernel malloc() function. It dereferences the second argument to the malloc_type structure and then quantizes the size of the mallocs being made according to the malloc type name. The script: fbt:kernel:malloc:entry { mt = (struct malloc_type *) arg1; @[stringof(mt->ks_shortdesc)] = quantize(arg0) } The output: vmem value ------------- Distribution ------------- count 2 | 0 4 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ 56 8 | 0 ufs_dirhash value ------------- Distribution ------------- count 4 | 0 8 |@@@@@@@@@@@@@@@@@@@@@@@@@@@ 6 16 | 0 32 | 0 64 | 0 128 | 0 256 |@@@@@@@@@@@@@ 3 512 | 0 UMAHash value ------------- Distribution ------------- count 512 | 0 1024 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ 1 2048 | 0 vnodemarker value ------------- Distribution ------------- count 128 | 0 256 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ 6 512 | 0 Unitno value ------------- Distribution ------------- count 8 | 0 16 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ 130 32 | 0 sysctl value ------------- Distribution ------------- count 4 | 0 8 |@@@@@@@@@@@@@@@@@@ 77 16 |@@@@@@@@@@@@@@@@@@@@@@ 95 32 | 0 DEVFS3 value ------------- Distribution ------------- count 32 | 0 64 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ 56 128 | 0 plimit value ------------- Distribution ------------- count 64 | 0 128 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ 28 256 | 0 proc-args value ------------- Distribution ------------- count 16 | 0 32 |@@@@@@@@@@@@@@@@@@@@@@ 48 64 |@@@@@@@@@@@@@@@@@@ 38 128 | 0 zombie value ------------- Distribution ------------- count 32 | 0 64 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ 86 128 | 0 kmem value ------------- Distribution ------------- count 16 | 0 32 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@ 24 64 | 0 128 | 0 256 | 0 512 |@@@@@@@@@@@@ 10 1024 | 0 sysctltmp value ------------- Distribution ------------- count 2 | 0 4 |@@@@@ 28 8 |@@@@@@@@@@ 56 16 |@@@@@@@@@@ 56 32 |@@@@@@@@@@ 56 64 | 0 128 |@@@@@ 28 256 | 0 filedesc value ------------- Distribution ------------- count 64 | 0 128 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ 86 256 | 0 nfsclient_req value ------------- Distribution ------------- count 32 | 0 64 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ 213 128 | 0 DEVFS1 value ------------- Distribution ------------- count 64 | 0 128 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ 112 256 | 0 ioctlops value ------------- Distribution ------------- count 2 | 0 4 |@@@@@@@@@@@@@@@@@@@@ 573 8 |@ 30 16 |@@ 60 32 |@@@@@@@@@ 264 64 |@@ 60 128 | 0 256 |@@@@@@ 175 512 | 0 soname value ------------- Distribution ------------- count 8 | 0 16 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ 8991 32 | 0 subproc value ------------- Distribution ------------- count 1024 | 0 2048 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ 86 4096 | 0 cred value ------------- Distribution ------------- count 32 | 0 64 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ 10403 128 | 0 nfsserver_srvdesc value ------------- Distribution ------------- count 4 | 0 8 |@@@@@@@@@@@@@@@@@@@@ 8991 16 | 0 32 | 0 64 | 0 128 |@@@@@@@@@@@@@@@@@@@@ 8991 256 | 0 temp value ------------- Distribution ------------- count 4 | 0 8 |@@@@@@@@@@@@@ 935 16 |@@ 151 32 |@@@ 184 64 |@ 66 128 |@ 97 256 | 30 512 | 22 1024 | 13 2048 | 4 4096 | 28 8192 |@@@@@@@@@@@@@@@@@@@ 1359 16384 | 0 dtrace value ------------- Distribution ------------- count 0 | 0 1 |@ 23 2 | 19 4 |@@@ 118 8 |@@@@@ 182 16 |@@@@@ 211 32 |@@@@@@@@@@@@@@@@@ 689 64 |@ 31 128 |@ 29 256 |@@ 99 512 |@ 24 1024 |@@@ 135 2048 | 5 4096 | 0 8192 | 0 16384 | 0 32768 | 0 65536 | 0 131072 | 0 262144 | 0 524288 | 0 1048576 | 10 2097152 | 0 4194304 |@ 20 8388608 | 0 There is still a lot of work to do and while that goes on, the code has to remain in the FreeBSD perforce server. It isn't ready to get merged into CVS-current yet. I have asked the perforce-admins to mirror the project out to CVS (via cvsup10.freebsd.org), but I'm not sure what the hold-up there is. I had hoped that one or two of the Google SoC students would contribute to this, but I only received one proposal and that wasn't for anything that would help get DTrace/FreeBSD completed. There are things people can do to help. Some of them are build related; some are build tool related; some are user-land DTrace specific; and the rest are kernel related. Speak up if you are interested in working on this! -- John Birrell
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