A fix to allow named unit masks to be used as the default was recently
pushed upstream (Jun 24: Add support for named default unit masks), but
unfortunately, we all missed the fact that using a named default
unit mask didn't actually work insofar as counting events.
Here's an example on Sandybridge that should use the default named
unit mask "any":
operf -e uops_issued:2000000 ./my_test
and opreport shows "opreport error: No sample file found".
When the user does not specify a unit mask, the profiling tools
(as well as ocount) will use 'ophelp --unit-mask' to determine
what the default unit mask should be. All of the oprofile
tools -- operf, opcontrol, ocount -- expect a numerical value
to be returned. So, in the case of a named default unit mask,
the unit mask name returned by ophelp was not being handled
properly, and the end result was usually "No samples found"
by opreport (or zero event counts by ocount). This patch
fixes this problem.
Signed-off-by: Maynard Johnson <firstname.lastname@example.org>