Re: [PATCH v7 2/2] perf cs-etm: Split --dump-raw-trace by AUX records
From: Leo Yan <hidden>
Date: 2021-06-28 01:27:58
Also in:
linux-perf-users, lkml
Hi James, On Thu, Jun 24, 2021 at 05:43:03PM +0100, James Clark wrote:
Currently --dump-raw-trace skips queueing and splitting buffers because
of an early exit condition in cs_etm__process_auxtrace_info(). Once
that is removed we can print the split data by using the queues
and searching for split buffers with the same reference as the
one that is currently being processed.
This keeps the same behaviour of dumping in file order when an AUXTRACE
event appears, rather than moving trace dump to where AUX records are in
the file.
There will be a newline and size printout for each fragment. For example
this buffer is comprised of two AUX records, but was printed as one:
0 0 0x8098 [0x30]: PERF_RECORD_AUXTRACE size: 0xa0 offset: 0 ref: 0x491a4dfc52fc0e6e idx: 0 t
. ... CoreSight ETM Trace data: size 160 bytes
Idx:0; ID:10; I_ASYNC : Alignment Synchronisation.
Idx:12; ID:10; I_TRACE_INFO : Trace Info.; INFO=0x0 { CC.0 }
Idx:17; ID:10; I_ADDR_L_64IS0 : Address, Long, 64 bit, IS0.; Addr=0x0000000000000000;
Idx:80; ID:10; I_ASYNC : Alignment Synchronisation.
Idx:92; ID:10; I_TRACE_INFO : Trace Info.; INFO=0x0 { CC.0 }
Idx:97; ID:10; I_ADDR_L_64IS0 : Address, Long, 64 bit, IS0.; Addr=0xFFFFDE2AD3FD76D4;
But is now printed as two fragments:
0 0 0x8098 [0x30]: PERF_RECORD_AUXTRACE size: 0xa0 offset: 0 ref: 0x491a4dfc52fc0e6e idx: 0 t
. ... CoreSight ETM Trace data: size 80 bytes
Idx:0; ID:10; I_ASYNC : Alignment Synchronisation.
Idx:12; ID:10; I_TRACE_INFO : Trace Info.; INFO=0x0 { CC.0 }
Idx:17; ID:10; I_ADDR_L_64IS0 : Address, Long, 64 bit, IS0.; Addr=0x0000000000000000;
. ... CoreSight ETM Trace data: size 80 bytes
Idx:80; ID:10; I_ASYNC : Alignment Synchronisation.
Idx:92; ID:10; I_TRACE_INFO : Trace Info.; INFO=0x0 { CC.0 }
Idx:97; ID:10; I_ADDR_L_64IS0 : Address, Long, 64 bit, IS0.; Addr=0xFFFFDE2AD3FD76D4;
Decoding errors that appeared in problematic files are now not present,
for example:
Idx:808; ID:1c; I_BAD_SEQUENCE : Invalid Sequence in packet.[I_ASYNC]
...
PKTP_ETMV4I_0016 : 0x0014 (OCSD_ERR_INVALID_PCKT_HDR) [Invalid packet header]; TrcIdx=822
Signed-off-by: James Clark <redacted>I tested this patch and the result looks good for me. I found a side effect introduced by this change is the perf raw dump also synthesizes events PERF_RECORD_ATTR. This is because function cs_etm__synth_events() will execute after applying this patch and it synthesizes PERF_RECORD_ATTR events. I don't see any harm for this, so: Tested-by: Leo Yan <redacted> Please see an extra comment in below.
quoted hunk ↗ jump to hunk
--- tools/perf/util/cs-etm.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-)diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c index 88e8122f73c9..ad777c2a342f 100644 --- a/tools/perf/util/cs-etm.c +++ b/tools/perf/util/cs-etm.c@@ -2430,6 +2430,22 @@ static int cs_etm__process_event(struct perf_session *session, return 0; } +static void dump_queued_data(struct cs_etm_auxtrace *etm, + struct perf_record_auxtrace *event) +{ + struct auxtrace_buffer *buf; + unsigned int i; + /* + * Find all buffers with same reference in the queues and dump them. + * This is because the queues can contain multiple entries of the same + * buffer that were split on aux records. + */ + for (i = 0; i < etm->queues.nr_queues; ++i) + list_for_each_entry(buf, &etm->queues.queue_array[i].head, list) + if (buf->reference == event->reference) + cs_etm__dump_event(etm, buf); +} + static int cs_etm__process_auxtrace_event(struct perf_session *session, union perf_event *event, struct perf_tool *tool __maybe_unused)@@ -2462,7 +2478,8 @@ static int cs_etm__process_auxtrace_event(struct perf_session *session, cs_etm__dump_event(etm, buffer); auxtrace_buffer__put_data(buffer); } - } + } else if (dump_trace) + dump_queued_data(etm, &event->auxtrace);
IIUC, in the function cs_etm__process_auxtrace_event(), since
"etm->data_queued" is always true, below flow will never run:
if (!etm->data_queued) {
......
if (dump_trace)
if (auxtrace_buffer__get_data(buffer, fd)) {
cs_etm__dump_event(etm, buffer);
auxtrace_buffer__put_data(buffer);
}
}
If so, it's better to use a new patch to polish the code.
Thanks,
Leo
quoted hunk ↗ jump to hunk
return 0; }@@ -3038,7 +3055,6 @@ int cs_etm__process_auxtrace_info(union perf_event *event, if (dump_trace) { cs_etm__print_auxtrace_info(auxtrace_info->priv, num_cpu); - return 0; } err = cs_etm__synth_events(etm, session);-- 2.28.0
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