K 10
svn:author
V 3
jtl
K 8
svn:date
V 27
2015-11-14T01:45:55.585816Z
K 7
svn:log
V 343
Optimizations to the way hwpmc gathers user callchains

Changes to the code to gather user stacks:
* Delay setting pmc_cpumask until we actually have the stack.
* When recording user stack traces, only walk the portion of the ring
  that should have samples for us.

Sponsored by:	Juniper Networks
Approved by:	gnn (mentor)
MFC after:	1 month

END