This is the mail archive of the
systemtap@sourceware.org
mailing list for the systemtap project.
Re: "stap -u" testing
- From: fche at redhat dot com (Frank Ch. Eigler)
- To: Mike Mason <mmlnx at us dot ibm dot com>
- Cc: systemtap at sources dot redhat dot com
- Date: 29 Jan 2007 11:56:33 -0500
- Subject: Re: "stap -u" testing
- References: <45BE2042.4070604@us.ibm.com>
Mike Mason <mmlnx@us.ibm.com> writes:
> As far as I can tell, none of the tests invoke stap with the -u
> option (unoptimized mode). Doing so is revealing (see examples
> below). [...]
It would be worthwhile to review the history of the -u option in the
archives. One will see that one of its motivations was specifically
to minimize the effect of unpredictably incomplete debugging
information for some $target variables. This way, only those
variables actually used by end-user script code are asserted to exist,
and tapsets can be optimistic in a sense.
It is true that this option can also mask cases where the named
$target variables are completely wrong (that is, not present on any
supportworthy kernel version). The difficulty lies in telling apart
this class from the other one.
- FChE