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perf intel-pt: Add support for decoding PSB+ only
A single q option decodes ip from only FUP/TIP packets. Make it so that repeating the q option (i.e. qq) decodes only PSB+, getting ip if there is a FUP packet within PSB+ (i.e. between PSB and PSBEND). Example: $ perf record -e intel_pt//u grep -rI pudding drivers [ perf record: Woken up 52 times to write data ] [ perf record: Captured and wrote 57.870 MB perf.data ] $ time perf script --itrace=bi | wc -l 58948289 real 1m23.863s user 1m23.251s sys 0m7.452s $ time perf script --itrace=biq | wc -l 3385694 real 0m4.453s user 0m4.455s sys 0m0.328s $ time perf script --itrace=biqq | wc -l 1883 real 0m0.047s user 0m0.043s sys 0m0.009s Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Reviewed-by: Andi Kleen <ak@linux.intel.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Link: http://lore.kernel.org/lkml/20200710151104.15137-13-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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@ -999,6 +999,21 @@ What *will* be decoded with the (single) q option:
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Note the q option does not specify what events will be synthesized e.g. the p
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option must be used also to show power events.
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Repeating the q option (double-q i.e. qq) results in even faster decoding and even
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less detail. The decoder decodes only extended PSB (PSB+) packets, getting the
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instruction pointer if there is a FUP packet within PSB+ (i.e. between PSB and
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PSBEND). Note PSB packets occur regularly in the trace based on the psb_period
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config term (refer config terms section). There will be a FUP packet if the
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PSB+ occurs while control flow is being traced.
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What will *not* be decoded with the qq option:
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- everything except instruction pointer associated with PSB packets
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What *will* be decoded with the qq option:
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- instruction pointer associated with PSB packets
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dump option
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~~~~~~~~~~~
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@ -113,6 +113,7 @@ struct intel_pt_decoder {
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bool in_psb;
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bool hop;
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bool hop_psb_fup;
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bool leap;
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enum intel_pt_param_flags flags;
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uint64_t pos;
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uint64_t last_ip;
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@ -240,6 +241,7 @@ struct intel_pt_decoder *intel_pt_decoder_new(struct intel_pt_params *params)
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decoder->return_compression = params->return_compression;
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decoder->branch_enable = params->branch_enable;
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decoder->hop = params->quick >= 1;
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decoder->leap = params->quick >= 2;
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decoder->flags = params->flags;
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@ -1903,9 +1905,18 @@ static int intel_pt_resample(struct intel_pt_decoder *decoder)
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#define HOP_RETURN 2
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#define HOP_AGAIN 3
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static int intel_pt_scan_for_psb(struct intel_pt_decoder *decoder);
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/* Hop mode: Ignore TNT, do not walk code, but get ip from FUPs and TIPs */
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static int intel_pt_hop_trace(struct intel_pt_decoder *decoder, bool *no_tip, int *err)
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{
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/* Leap from PSB to PSB, getting ip from FUP within PSB+ */
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if (decoder->leap && !decoder->in_psb && decoder->packet.type != INTEL_PT_PSB) {
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*err = intel_pt_scan_for_psb(decoder);
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if (*err)
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return HOP_RETURN;
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}
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switch (decoder->packet.type) {
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case INTEL_PT_TNT:
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return HOP_IGNORE;
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@ -2681,6 +2692,7 @@ static int intel_pt_sync(struct intel_pt_decoder *decoder)
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decoder->ip = 0;
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intel_pt_clear_stack(&decoder->stack);
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leap:
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err = intel_pt_scan_for_psb(decoder);
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if (err)
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return err;
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@ -2702,6 +2714,12 @@ static int intel_pt_sync(struct intel_pt_decoder *decoder)
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decoder->pkt_state = INTEL_PT_STATE_RESAMPLE;
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else
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decoder->pkt_state = INTEL_PT_STATE_IN_SYNC;
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} else if (decoder->leap) {
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/*
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* In leap mode, only PSB+ is decoded, so keeping leaping to the
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* next PSB until there is an ip.
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*/
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goto leap;
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} else {
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return intel_pt_sync_ip(decoder);
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}
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