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 <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Paul Mackerras <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Arnaldo Carvalho de Melo <[email protected]> --- arch/metag/kernel/perf/perf_event.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/metag/kernel/perf/perf_event.c b/arch/metag/kernel/perf/perf_event.c index f38bf6d..8096db2 100644 --- a/arch/metag/kernel/perf/perf_event.c +++ b/arch/metag/kernel/perf/perf_event.c @@ -211,7 +211,7 @@ again: /* * 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); } -- 1.8.1.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
