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    Subject[PATCH 5.0 200/238] perf intel-pt: Fix CYC timestamp calculation after OVF
    Date
    5.0-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Adrian Hunter <adrian.hunter@intel.com>

    commit 03997612904866abe7cdcc992784ef65cb3a4b81 upstream.

    CYC packet timestamp calculation depends upon CBR which was being
    cleared upon overflow (OVF). That can cause errors due to failing to
    synchronize with sideband events. Even if a CBR change has been lost,
    the old CBR is still a better estimate than zero. So remove the clearing
    of CBR.

    Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
    Cc: Jiri Olsa <jolsa@redhat.com>
    Cc: stable@vger.kernel.org
    Link: http://lkml.kernel.org/r/20190206103947.15750-4-adrian.hunter@intel.com
    Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    tools/perf/util/intel-pt-decoder/intel-pt-decoder.c | 1 -
    1 file changed, 1 deletion(-)

    --- a/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c
    +++ b/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c
    @@ -1394,7 +1394,6 @@ static int intel_pt_overflow(struct inte
    {
    intel_pt_log("ERROR: Buffer overflow\n");
    intel_pt_clear_tx_flags(decoder);
    - decoder->cbr = 0;
    decoder->timestamp_insn_cnt = 0;
    decoder->pkt_state = INTEL_PT_STATE_ERR_RESYNC;
    decoder->overflow = true;

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