From: Adrian Hunter <adrian.hunter@xxxxxxxxx> The MTC packet provides a 8-bit slice of CTC which is related to TSC by the TMA packet, however the TMA packet only provides the lower 16 bits of CTC. If mtc_shift > 8 then some of the MTC bits are not in the CTC provided by the TMA packet. Fix-up the last_mtc calculated from the TMA packet by copying the missing bits from the current MTC assuming the least difference between the two, and that the current MTC comes after last_mtc. Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx> Cc: Jiri Olsa <jolsa@xxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx # v4.3+ Link: http://lkml.kernel.org/r/1475062896-22274-2-git-send-email-adrian.hunter@xxxxxxxxx Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> --- .../perf/util/intel-pt-decoder/intel-pt-decoder.c | 36 ++++++++++++++++++++++ 1 file changed, 36 insertions(+) diff --git a/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c b/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c index 3d1d446f037f..16c06d3ae577 100644 --- a/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c +++ b/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c @@ -90,6 +90,7 @@ struct intel_pt_decoder { bool pge; bool have_tma; bool have_cyc; + bool fixup_last_mtc; uint64_t pos; uint64_t last_ip; uint64_t ip; @@ -586,10 +587,31 @@ struct intel_pt_calc_cyc_to_tsc_info { uint64_t tsc_timestamp; uint64_t timestamp; bool have_tma; + bool fixup_last_mtc; bool from_mtc; double cbr_cyc_to_tsc; }; +/* + * MTC provides a 8-bit slice of CTC but the TMA packet only provides the lower + * 16 bits of CTC. If mtc_shift > 8 then some of the MTC bits are not in the CTC + * provided by the TMA packet. Fix-up the last_mtc calculated from the TMA + * packet by copying the missing bits from the current MTC assuming the least + * difference between the two, and that the current MTC comes after last_mtc. + */ +static void intel_pt_fixup_last_mtc(uint32_t mtc, int mtc_shift, + uint32_t *last_mtc) +{ + uint32_t first_missing_bit = 1U << (16 - mtc_shift); + uint32_t mask = ~(first_missing_bit - 1); + + *last_mtc |= mtc & mask; + if (*last_mtc >= mtc) { + *last_mtc -= first_missing_bit; + *last_mtc &= 0xff; + } +} + static int intel_pt_calc_cyc_cb(struct intel_pt_pkt_info *pkt_info) { struct intel_pt_decoder *decoder = pkt_info->decoder; @@ -619,6 +641,11 @@ static int intel_pt_calc_cyc_cb(struct intel_pt_pkt_info *pkt_info) return 0; mtc = pkt_info->packet.payload; + if (decoder->mtc_shift > 8 && data->fixup_last_mtc) { + data->fixup_last_mtc = false; + intel_pt_fixup_last_mtc(mtc, decoder->mtc_shift, + &data->last_mtc); + } if (mtc > data->last_mtc) mtc_delta = mtc - data->last_mtc; else @@ -687,6 +714,7 @@ static int intel_pt_calc_cyc_cb(struct intel_pt_pkt_info *pkt_info) data->ctc_delta = 0; data->have_tma = true; + data->fixup_last_mtc = true; return 0; @@ -753,6 +781,7 @@ static void intel_pt_calc_cyc_to_tsc(struct intel_pt_decoder *decoder, .tsc_timestamp = decoder->tsc_timestamp, .timestamp = decoder->timestamp, .have_tma = decoder->have_tma, + .fixup_last_mtc = decoder->fixup_last_mtc, .from_mtc = from_mtc, .cbr_cyc_to_tsc = 0, }; @@ -1271,6 +1300,7 @@ static void intel_pt_calc_tma(struct intel_pt_decoder *decoder) } decoder->ctc_delta = 0; decoder->have_tma = true; + decoder->fixup_last_mtc = true; intel_pt_log("CTC timestamp " x64_fmt " last MTC %#x CTC rem %#x\n", decoder->ctc_timestamp, decoder->last_mtc, ctc_rem); } @@ -1285,6 +1315,12 @@ static void intel_pt_calc_mtc_timestamp(struct intel_pt_decoder *decoder) mtc = decoder->packet.payload; + if (decoder->mtc_shift > 8 && decoder->fixup_last_mtc) { + decoder->fixup_last_mtc = false; + intel_pt_fixup_last_mtc(mtc, decoder->mtc_shift, + &decoder->last_mtc); + } + if (mtc > decoder->last_mtc) mtc_delta = mtc - decoder->last_mtc; else -- 2.7.4 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html