On Dec 3, 2007 3:12 PM, Adam Leventhal <[EMAIL PROTECTED]> wrote:
> On Mon, Dec 03, 2007 at 02:41:20PM -0600, Mike Gerdts wrote:
> > Would it be reasonable to consider adding probes to RPC library
> > functions (usr/src/lib/libnsl/rpc/*.c) to provide generic methods for
> > tracing RPC's?  While probes that aren't enabled have no impact to a
> > running process, I don't think I understand how the existence of the
> > probes gets registered with the kernel to understand the impact on
> > process startup.  That is, if libnsl had some USDT probes in it, would
> > it have a measurable impact on the startup time of programs that link
> > against libnsl?
>
> Absolutely. Adding USDT probes to libnsl would be a great idea.

Is there some updated documentation that helps out with less trivial
USDT probes?  The wikified dtrace manual[1] isn't too helpful when you
want to provide access to data structures.

I figured that there must be an example to learn from, so I went
looking through the ON source and under usr/src/cmd iscsitgtd seems to
be the only command with USDT probes[2].  Based upon the iscsitgtd
source, it looks like I would need to use translators[3].  However,
in usr/src/cmd/iscsi/iscsitgtd/*.c I don't see any DTRACE_PROBE*()
calls so I suspect that something more advanced (less labor
intensive?) is being done.

1.http://wikis.sun.com/display/DTrace/Statically+Defined+Tracing+for+User+Applications
2.http://cvs.opensolaris.org/source/xref/onnv/onnv-gate/usr/src/cmd/iscsi/iscsitgtd/iscsi_provider.d
3.http://wikis.sun.com/display/DTrace/Translators

Any clues you can throw my way would be most appreciated.

-- 
Mike Gerdts
http://mgerdts.blogspot.com/
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