On Mon, Jun 28, 2021 at 11:38:34AM +0100, James Clark wrote:

[...]

quoted

quoted

 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.

Hi Leo,

I think this is not true in piped mode because there is no auxtrace index.
In that mode, events are processed only in file order and cs_etm__process_auxtrace_event()
is called for each buffer.

You can reproduce this with something like this:

     ./perf record -o - ls > stdio.data
     cat stdio.data | ./perf report -i -

You are right!  I tried these two commands with cs_etm event, just as
you said, in this case, the AUX trace data is not queued; so the flow
for "if (!etm->data_queued)" should be kept.  If so, I am very fine
for current change.  Thanks for sharing the knowledge.

There are some other Coresight features that don't work as expected in this mode, like
sorting timestamps between CPUs. The aux split patchset won't work either because random
access isn't possible. And the TRBE patch that I'm working on now won't work, because it
also requires the random access to lookup the flags on the AUX record to configure the 
decoder for unformatted trace.

Cool, looking forward for the patches :)

Leo

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