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perf intel-pt: Add support for decoding FUP/TIP only
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Use the new itrace 'q' option to add support for a mode of decoding that
ignores TNT, does not walk object code, but gets the ip from FUP and TIP
packets.

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

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/20200710151104.15137-12-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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@ahunter6 @acmel
ahunter6 authored and acmel committed Aug 6, 2020
1 parent 5197153 commit 7c1b16b
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Showing 4 changed files with 200 additions and 5 deletions.
31 changes: 31 additions & 0 deletions tools/perf/Documentation/perf-intel-pt.txt
View file
Original file line number Diff line number Diff line change
Expand Up @@ -825,6 +825,7 @@ The letters are:
l synthesize last branch entries (use with i or x)
L synthesize last branch entries on existing event records
s skip initial number of events
q quicker (less detailed) decoding

"Instructions" events look like they were recorded by "perf record -e
instructions".
Expand Down Expand Up @@ -969,6 +970,36 @@ at the beginning. This is useful to ignore initialization code.

skips the first million instructions.

The q option changes the way the trace is decoded. The decoding is much faster
but much less detailed. Specifically, with the q option, the decoder does not
decode TNT packets, and does not walk object code, but gets the ip from FUP and
TIP packets. The q option can be used with the b and i options but the period
is not used. The q option decodes more quickly, but is useful only if the
control flow of interest is represented or indicated by FUP, TIP, TIP.PGE, or
TIP.PGD packets (refer below). However the q option could be used to find time
ranges that could then be decoded fully using the --time option.

What will *not* be decoded with the (single) q option:

- direct calls and jmps
- conditional branches
- non-branch instructions

What *will* be decoded with the (single) q option:

- asynchronous branches such as interrupts
- indirect branches
- function return target address *if* the noretcomp config term (refer
config terms section) was used
- start of (control-flow) tracing
- end of (control-flow) tracing, if it is not out of context
- power events, ptwrite, transaction start and abort
- instruction pointer associated with PSB packets

Note the q option does not specify what events will be synthesized e.g. the p
option must be used also to show power events.


dump option
~~~~~~~~~~~

Expand Down
167 changes: 163 additions & 4 deletions tools/perf/util/intel-pt-decoder/intel-pt-decoder.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -55,6 +55,7 @@ enum intel_pt_pkt_state {
INTEL_PT_STATE_TIP_PGD,
INTEL_PT_STATE_FUP,
INTEL_PT_STATE_FUP_NO_TIP,
INTEL_PT_STATE_RESAMPLE,
};

static inline bool intel_pt_sample_time(enum intel_pt_pkt_state pkt_state)
Expand All @@ -65,6 +66,7 @@ static inline bool intel_pt_sample_time(enum intel_pt_pkt_state pkt_state)
case INTEL_PT_STATE_ERR_RESYNC:
case INTEL_PT_STATE_IN_SYNC:
case INTEL_PT_STATE_TNT_CONT:
case INTEL_PT_STATE_RESAMPLE:
return true;
case INTEL_PT_STATE_TNT:
case INTEL_PT_STATE_TIP:
Expand Down Expand Up @@ -109,6 +111,8 @@ struct intel_pt_decoder {
bool fixup_last_mtc;
bool have_last_ip;
bool in_psb;
bool hop;
bool hop_psb_fup;
enum intel_pt_param_flags flags;
uint64_t pos;
uint64_t last_ip;
Expand Down Expand Up @@ -235,6 +239,7 @@ struct intel_pt_decoder *intel_pt_decoder_new(struct intel_pt_params *params)
decoder->data = params->data;
decoder->return_compression = params->return_compression;
decoder->branch_enable = params->branch_enable;
decoder->hop = params->quick >= 1;

decoder->flags = params->flags;

Expand Down Expand Up @@ -275,6 +280,9 @@ struct intel_pt_decoder *intel_pt_decoder_new(struct intel_pt_params *params)
intel_pt_log("timestamp: tsc_ctc_mult %u\n", decoder->tsc_ctc_mult);
intel_pt_log("timestamp: tsc_slip %#x\n", decoder->tsc_slip);

if (decoder->hop)
intel_pt_log("Hop mode: decoding FUP and TIPs, but not TNT\n");

return decoder;
}

Expand Down Expand Up @@ -1730,8 +1738,14 @@ static int intel_pt_walk_psbend(struct intel_pt_decoder *decoder)

case INTEL_PT_FUP:
decoder->pge = true;
if (decoder->packet.count)
if (decoder->packet.count) {
intel_pt_set_last_ip(decoder);
if (decoder->hop) {
/* Act on FUP at PSBEND */
decoder->ip = decoder->last_ip;
decoder->hop_psb_fup = true;
}
}
break;

case INTEL_PT_MODE_TSX:
Expand Down Expand Up @@ -1875,6 +1889,118 @@ static int intel_pt_walk_fup_tip(struct intel_pt_decoder *decoder)
}
}

static int intel_pt_resample(struct intel_pt_decoder *decoder)
{
decoder->pkt_state = INTEL_PT_STATE_IN_SYNC;
decoder->state.type = INTEL_PT_INSTRUCTION;
decoder->state.from_ip = decoder->ip;
decoder->state.to_ip = 0;
return 0;
}

#define HOP_PROCESS 0
#define HOP_IGNORE 1
#define HOP_RETURN 2
#define HOP_AGAIN 3

/* Hop mode: Ignore TNT, do not walk code, but get ip from FUPs and TIPs */
static int intel_pt_hop_trace(struct intel_pt_decoder *decoder, bool *no_tip, int *err)
{
switch (decoder->packet.type) {
case INTEL_PT_TNT:
return HOP_IGNORE;

case INTEL_PT_TIP_PGD:
if (!decoder->packet.count)
return HOP_IGNORE;
intel_pt_set_ip(decoder);
decoder->state.type |= INTEL_PT_TRACE_END;
decoder->state.from_ip = 0;
decoder->state.to_ip = decoder->ip;
return HOP_RETURN;

case INTEL_PT_TIP:
if (!decoder->packet.count)
return HOP_IGNORE;
intel_pt_set_ip(decoder);
decoder->state.type = INTEL_PT_INSTRUCTION;
decoder->state.from_ip = decoder->ip;
decoder->state.to_ip = 0;
return HOP_RETURN;

case INTEL_PT_FUP:
if (!decoder->packet.count)
return HOP_IGNORE;
intel_pt_set_ip(decoder);
if (intel_pt_fup_event(decoder))
return HOP_RETURN;
if (!decoder->branch_enable)
*no_tip = true;
if (*no_tip) {
decoder->state.type = INTEL_PT_INSTRUCTION;
decoder->state.from_ip = decoder->ip;
decoder->state.to_ip = 0;
return HOP_RETURN;
}
*err = intel_pt_walk_fup_tip(decoder);
if (!*err)
decoder->pkt_state = INTEL_PT_STATE_RESAMPLE;
return HOP_RETURN;

case INTEL_PT_PSB:
decoder->last_ip = 0;
decoder->have_last_ip = true;
decoder->hop_psb_fup = false;
*err = intel_pt_walk_psbend(decoder);
if (*err == -EAGAIN)
return HOP_AGAIN;
if (*err)
return HOP_RETURN;
if (decoder->hop_psb_fup) {
decoder->hop_psb_fup = false;
decoder->state.type = INTEL_PT_INSTRUCTION;
decoder->state.from_ip = decoder->ip;
decoder->state.to_ip = 0;
return HOP_RETURN;
}
if (decoder->cbr != decoder->cbr_seen) {
decoder->state.type = 0;
return HOP_RETURN;
}
return HOP_IGNORE;

case INTEL_PT_BAD:
case INTEL_PT_PAD:
case INTEL_PT_TIP_PGE:
case INTEL_PT_TSC:
case INTEL_PT_TMA:
case INTEL_PT_MODE_EXEC:
case INTEL_PT_MODE_TSX:
case INTEL_PT_MTC:
case INTEL_PT_CYC:
case INTEL_PT_VMCS:
case INTEL_PT_PSBEND:
case INTEL_PT_CBR:
case INTEL_PT_TRACESTOP:
case INTEL_PT_PIP:
case INTEL_PT_OVF:
case INTEL_PT_MNT:
case INTEL_PT_PTWRITE:
case INTEL_PT_PTWRITE_IP:
case INTEL_PT_EXSTOP:
case INTEL_PT_EXSTOP_IP:
case INTEL_PT_MWAIT:
case INTEL_PT_PWRE:
case INTEL_PT_PWRX:
case INTEL_PT_BBP:
case INTEL_PT_BIP:
case INTEL_PT_BEP:
case INTEL_PT_BEP_IP:
default:
return HOP_PROCESS;
}
}

static int intel_pt_walk_trace(struct intel_pt_decoder *decoder)
{
bool no_tip = false;
Expand All @@ -1885,6 +2011,19 @@ static int intel_pt_walk_trace(struct intel_pt_decoder *decoder)
if (err)
return err;
next:
if (decoder->hop) {
switch (intel_pt_hop_trace(decoder, &no_tip, &err)) {
case HOP_IGNORE:
continue;
case HOP_RETURN:
return err;
case HOP_AGAIN:
goto next;
default:
break;
}
}

switch (decoder->packet.type) {
case INTEL_PT_TNT:
if (!decoder->packet.count)
Expand Down Expand Up @@ -1914,6 +2053,12 @@ static int intel_pt_walk_trace(struct intel_pt_decoder *decoder)
decoder->state.from_ip = 0;
decoder->state.to_ip = decoder->ip;
decoder->state.type |= INTEL_PT_TRACE_BEGIN;
/*
* In hop mode, resample to get the to_ip as an
* "instruction" sample.
*/
if (decoder->hop)
decoder->pkt_state = INTEL_PT_STATE_RESAMPLE;
return 0;
}

Expand Down Expand Up @@ -2033,7 +2178,7 @@ static int intel_pt_walk_trace(struct intel_pt_decoder *decoder)

case INTEL_PT_MODE_TSX:
/* MODE_TSX need not be followed by FUP */
if (!decoder->pge) {
if (!decoder->pge || decoder->in_psb) {
intel_pt_update_in_tx(decoder);
break;
}
Expand Down Expand Up @@ -2424,7 +2569,11 @@ static int intel_pt_sync_ip(struct intel_pt_decoder *decoder)
if (err)
return err;

decoder->pkt_state = INTEL_PT_STATE_IN_SYNC;
/* In hop mode, resample to get the to_ip as an "instruction" sample */
if (decoder->hop)
decoder->pkt_state = INTEL_PT_STATE_RESAMPLE;
else
decoder->pkt_state = INTEL_PT_STATE_IN_SYNC;
decoder->overflow = false;

decoder->state.from_ip = 0;
Expand Down Expand Up @@ -2545,7 +2694,14 @@ static int intel_pt_sync(struct intel_pt_decoder *decoder)

if (decoder->ip) {
decoder->state.type = 0; /* Do not have a sample */
decoder->pkt_state = INTEL_PT_STATE_IN_SYNC;
/*
* In hop mode, resample to get the PSB FUP ip as an
* "instruction" sample.
*/
if (decoder->hop)
decoder->pkt_state = INTEL_PT_STATE_RESAMPLE;
else
decoder->pkt_state = INTEL_PT_STATE_IN_SYNC;
} else {
return intel_pt_sync_ip(decoder);
}
Expand Down Expand Up @@ -2609,6 +2765,9 @@ const struct intel_pt_state *intel_pt_decode(struct intel_pt_decoder *decoder)
if (err == -EAGAIN)
err = intel_pt_walk_trace(decoder);
break;
case INTEL_PT_STATE_RESAMPLE:
err = intel_pt_resample(decoder);
break;
default:
err = intel_pt_bug(decoder);
break;
Expand Down
1 change: 1 addition & 0 deletions tools/perf/util/intel-pt-decoder/intel-pt-decoder.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -250,6 +250,7 @@ struct intel_pt_params {
uint32_t tsc_ctc_ratio_n;
uint32_t tsc_ctc_ratio_d;
enum intel_pt_param_flags flags;
unsigned int quick;
};

struct intel_pt_decoder;
Expand Down
6 changes: 5 additions & 1 deletion tools/perf/util/intel-pt.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1030,6 +1030,7 @@ static struct intel_pt_queue *intel_pt_alloc_queue(struct intel_pt *pt,
params.mtc_period = intel_pt_mtc_period(pt);
params.tsc_ctc_ratio_n = pt->tsc_ctc_ratio_n;
params.tsc_ctc_ratio_d = pt->tsc_ctc_ratio_d;
params.quick = pt->synth_opts.quick;

if (pt->filts.cnt > 0)
params.pgd_ip = intel_pt_pgd_ip;
Expand Down Expand Up @@ -1423,7 +1424,10 @@ static int intel_pt_synth_instruction_sample(struct intel_pt_queue *ptq)

sample.id = ptq->pt->instructions_id;
sample.stream_id = ptq->pt->instructions_id;
sample.period = ptq->state->tot_insn_cnt - ptq->last_insn_cnt;
if (pt->synth_opts.quick)
sample.period = 1;
else
sample.period = ptq->state->tot_insn_cnt - ptq->last_insn_cnt;

sample.cyc_cnt = ptq->ipc_cyc_cnt - ptq->last_in_cyc_cnt;
if (sample.cyc_cnt) {
Expand Down

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