When calculating the delta, mask with MAX_PERIOD (24 bits) to handle
wrapping, which particularly happens with periodic sampling since the
value is intentionally set so that it will overflow soon.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
/*
* Calculate the delta and add it to the counter.
*/
- delta = new_raw_count - prev_raw_count;
+ delta = (new_raw_count - prev_raw_count) & MAX_PERIOD;
local64_add(delta, &event->count);
}