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Commit 3f04d98e authored by Adrian Hunter's avatar Adrian Hunter Committed by Arnaldo Carvalho de Melo
Browse files

perf intel-pt: Improve sample timestamp 



The decoder uses its current timestamp in samples. Usually that is a
timestamp that has already passed, but in some cases it is a timestamp
for a branch that the decoder is walking towards, and consequently
hasn't reached. Improve that situation by using the pkt_state to
determine when to use the current or previous timestamp.

Signed-off-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1495786658-18063-3-git-send-email-adrian.hunter@intel.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 22c06892

tools/perf/util/intel-pt-decoder/intel-pt-decoder.c

+31 −3
Original line number Diff line number Diff line
@@ -64,6 +64,25 @@ enum intel_pt_pkt_state { 
	INTEL_PT_STATE_FUP_NO_TIP,

};



static inline bool intel_pt_sample_time(enum intel_pt_pkt_state pkt_state)

{

	switch (pkt_state) {

	case INTEL_PT_STATE_NO_PSB:

	case INTEL_PT_STATE_NO_IP:

	case INTEL_PT_STATE_ERR_RESYNC:

	case INTEL_PT_STATE_IN_SYNC:

	case INTEL_PT_STATE_TNT:

		return true;

	case INTEL_PT_STATE_TIP:

	case INTEL_PT_STATE_TIP_PGD:

	case INTEL_PT_STATE_FUP:

	case INTEL_PT_STATE_FUP_NO_TIP:

		return false;

	default:

		return true;

	};

}



#ifdef INTEL_PT_STRICT

#define INTEL_PT_STATE_ERR1	INTEL_PT_STATE_NO_PSB

#define INTEL_PT_STATE_ERR2	INTEL_PT_STATE_NO_PSB
@@ -99,6 +118,7 @@ struct intel_pt_decoder { 
	uint64_t timestamp;

	uint64_t tsc_timestamp;

	uint64_t ref_timestamp;

	uint64_t sample_timestamp;

	uint64_t ret_addr;

	uint64_t ctc_timestamp;

	uint64_t ctc_delta;
@@ -139,6 +159,7 @@ struct intel_pt_decoder { 
	unsigned int fup_tx_flags;

	unsigned int tx_flags;

	uint64_t timestamp_insn_cnt;

	uint64_t sample_insn_cnt;

	uint64_t stuck_ip;

	int no_progress;

	int stuck_ip_prd;
@@ -898,6 +919,7 @@ static int intel_pt_walk_insn(struct intel_pt_decoder *decoder, 


	decoder->tot_insn_cnt += insn_cnt;

	decoder->timestamp_insn_cnt += insn_cnt;

	decoder->sample_insn_cnt += insn_cnt;

	decoder->period_insn_cnt += insn_cnt;



	if (err) {
@@ -2069,7 +2091,7 @@ static int intel_pt_sync(struct intel_pt_decoder *decoder) 


static uint64_t intel_pt_est_timestamp(struct intel_pt_decoder *decoder)

{

	uint64_t est = decoder->timestamp_insn_cnt << 1;

	uint64_t est = decoder->sample_insn_cnt << 1;



	if (!decoder->cbr || !decoder->max_non_turbo_ratio)

		goto out;
@@ -2077,7 +2099,7 @@ static uint64_t intel_pt_est_timestamp(struct intel_pt_decoder *decoder) 
	est *= decoder->max_non_turbo_ratio;

	est /= decoder->cbr;

out:

	return decoder->timestamp + est;

	return decoder->sample_timestamp + est;

}



const struct intel_pt_state *intel_pt_decode(struct intel_pt_decoder *decoder)
@@ -2133,11 +2155,17 @@ const struct intel_pt_state *intel_pt_decode(struct intel_pt_decoder *decoder) 
	if (err) {

		decoder->state.err = intel_pt_ext_err(err);

		decoder->state.from_ip = decoder->ip;

		decoder->sample_timestamp = decoder->timestamp;

		decoder->sample_insn_cnt = decoder->timestamp_insn_cnt;

	} else {

		decoder->state.err = 0;

		if (intel_pt_sample_time(decoder->pkt_state)) {

			decoder->sample_timestamp = decoder->timestamp;

			decoder->sample_insn_cnt = decoder->timestamp_insn_cnt;

		}

	}



	decoder->state.timestamp = decoder->timestamp;

	decoder->state.timestamp = decoder->sample_timestamp;

	decoder->state.est_timestamp = intel_pt_est_timestamp(decoder);

	decoder->state.cr3 = decoder->cr3;

	decoder->state.tot_insn_cnt = decoder->tot_insn_cnt;