perf: Report maximum values for counter overflow
authorBarret Rhoden <brho@cs.berkeley.edu>
Thu, 16 Jun 2016 19:34:45 +0000 (15:34 -0400)
committerBarret Rhoden <brho@cs.berkeley.edu>
Fri, 17 Jun 2016 16:17:55 +0000 (12:17 -0400)
commit624feb5f6ef6e448e78967949272fbd8f642a569
treed26e873e4638aae6cd3182c9fa2b4faae38915c1
parentd919318cbac7dc6ba99655238965f2d182d69296
perf: Report maximum values for counter overflow

The counters can overflow and wrap around.  Previously, if that happened,
we'd just report the wrapped value.  Now we'll report the maximum value.
Userspace (perf stat) can handle that if we'd like to.

Signed-off-by: Barret Rhoden <brho@cs.berkeley.edu>
kern/arch/x86/perfmon.c