On 18/03/2010, at 5:51 AM, David Young wrote:
On Mon, Mar 15, 2010 at 04:43:04AM +0000, Mindaugas Rasiukevicius wrote:Hi,David Young <dyoung%pobox.com@localhost> wrote:On Sat, Nov 21, 2009 at 03:41:07PM +1100, matthew green wrote:SPLDEBUG is single-purpose. It also has some bugs, which I am happy to describe. But let's keep it until we come up with something better.now you've told me all of: it's single purpose, MD, and doesn't work.please revert SPLDEBUG. it does not belong in sys/kern.Have a little patience. I am incorporating all of the suggestions thatI have heard so far into a patch.Is there any progress on this? IIIRC, general agreement was that subr_spldebug.c does not belong to sys/kern.Can you respond?I plan to commit my final patches in this area for posterity, and then to remove the feature just as soon as DTrace is capable of providing it. I don't think that there are FBT probes on all of the relevant assembly-language routines, yet.
The FBT provider can't instrument assembly language routines because they don't follow the standard C entry setup and exit teardown code. The may be able to be hand-instrumented with SDT probe calls, but that will add the overhead of a test and branch for each probe. Regards, Darran.