perf stat: Fix bug in handling events in error state
(This is a patch has been sitting in the Intel CQM/CMT driver series for a while, despite not depend on it. Sending it now independently since the series is being discarded.) When an event is in error state, read() returns 0 instead of sizeof() buffer. In certain modes, such as interval printing, ignoring the 0 return value may cause bogus count deltas to be computed and thus invalid results printed. This patch fixes this problem by modifying read_counters() to mark the event as not scaled (scaled = -1) to force the printout routine to show <NOT COUNTED>. Signed-off-by: NStephane Eranian <eranian@google.com> Reviewed-by: NDavid Carrillo-Cisneros <davidcc@google.com> Acked-by: NJiri Olsa <jolsa@redhat.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Mathieu Poirier <mathieu.poirier@linaro.org> Cc: Paul Turner <pjt@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Wang Nan <wangnan0@huawei.com> Link: http://lkml.kernel.org/r/20170412182301.44406-1-davidcc@google.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
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