linux.git/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c, branch vsnprintf

perf cs-etm: Use new OpenCSD consistency checks

2024-09-24T18:46:46+00:00

Previously when the incorrect binary was used for decode, Perf would
silently continue to generate incorrect samples. With OpenCSD 1.5.4 we
can enable consistency checks that do a best effort to detect a mismatch
in the image. When one is detected a warning is printed and sample
generation stops until the trace resynchronizes with a good part of the
image.

Reported-by: Ganapatrao Kulkarni 
Closes: https://lore.kernel.org/all/20240719092619.274730-1-gankulkarni@os.amperecomputing.com/
Reviewed-by: Leo Yan 
Signed-off-by: James Clark 
Tested-by: Ganapatrao Kulkarni 
Cc: Ben Gainey 
Cc: Suzuki K Poulose 
Cc: Will Deacon 
Cc: Mathieu Poirier 
Cc: Mike Leach 
Cc: Ruidong Tian 
Cc: Leo Yan 
Cc: Benjamin Gray 
Cc: linux-arm-kernel@lists.infradead.org
Cc: coresight@lists.linaro.org
Cc: John Garry 
Cc: scclevenger@os.amperecomputing.com
Link: https://lore.kernel.org/r/20240916135743.1490403-3-james.clark@linaro.org
Signed-off-by: Namhyung Kim

perf: cs-etm: Print queue number in raw trace dump

2024-08-29T18:56:37+00:00

Now that we have overlapping trace IDs it's also useful to know what the
queue number is to be able to distinguish the source of the trace so
print it inline. Hide it behind the -v option because it might not be
obvious to users what the queue number is.

Reviewed-by: Mike Leach 
Signed-off-by: James Clark 
Cc: Adrian Hunter 
Cc: Alexander Shishkin 
Cc: Alexandre Torgue 
Cc: Anshuman Khandual 
Cc: Ganapatrao Kulkarni 
Cc: Ian Rogers 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: John Garry 
Cc: Kan Liang 
Cc: Leo Yan 
Cc: Mark Rutland 
Cc: Maxime Coquelin 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Suzuki Poulouse 
Cc: Will Deacon 
Link: https://lore.kernel.org/r/20240722101202.26915-8-james.clark@linaro.org
Signed-off-by: James Clark 
Signed-off-by: Arnaldo Carvalho de Melo

perf: cs-etm: Create decoders based on the trace ID mappings

2024-08-29T18:55:24+00:00

Now that each queue has a unique set of trace ID mappings, use this
list to create the decoders. In unformatted mode just add a single
mapping so only one decoder is made.

Previously each queue would have a decoder created for each traced CPU
on the system but this won't work anymore because CPUs can have
overlapping trace IDs.

This also means that the CORESIGHT_TRACE_ID_UNUSED_FLAG isn't needed
any more. If mappings aren't added then decoders aren't created, rather
than needing a flag to suppress creation.

Reviewed-by: Mike Leach 
Signed-off-by: James Clark 
Cc: Adrian Hunter 
Cc: Alexander Shishkin 
Cc: Alexandre Torgue 
Cc: Anshuman Khandual 
Cc: Ganapatrao Kulkarni 
Cc: Ian Rogers 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: John Garry 
Cc: Kan Liang 
Cc: Leo Yan 
Cc: Mark Rutland 
Cc: Maxime Coquelin 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Suzuki Poulouse 
Cc: Will Deacon 
Link: https://lore.kernel.org/r/20240722101202.26915-5-james.clark@linaro.org
Signed-off-by: James Clark 
Signed-off-by: Arnaldo Carvalho de Melo

perf: cs-etm: Move traceid_list to each queue

2024-08-29T18:54:40+00:00

The global list won't work for per-sink trace ID allocations, so put a
list in each queue where the IDs will be unique to that queue.

To keep the same behavior as before, for version 0 of the HW_ID packets,
copy all the HW_ID mappings into all queues.

This change doesn't effect the decoders, only trace ID lookups on the
Perf side. The decoders are still created with global mappings which
will be fixed in a later commit.

Reviewed-by: Mike Leach 
Signed-off-by: James Clark 
Cc: Adrian Hunter 
Cc: Alexander Shishkin 
Cc: Alexandre Torgue 
Cc: Anshuman Khandual 
Cc: Ganapatrao Kulkarni 
Cc: Ian Rogers 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: John Garry 
Cc: Kan Liang 
Cc: Leo Yan 
Cc: Mark Rutland 
Cc: Maxime Coquelin 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Suzuki Poulouse 
Cc: Will Deacon 
Link: https://lore.kernel.org/r/20240722101202.26915-4-james.clark@linaro.org
Signed-off-by: James Clark 
Signed-off-by: Arnaldo Carvalho de Melo

perf cs-etm: Add exception level consistency check

2023-06-12T21:18:13+00:00

Assert that our own tracking of the exception level matches what
OpenCSD provides. OpenCSD doesn't distinguish between EL0 and EL1 in the
memory access callback so the extra tracking was required. But a rough
assert can still be done.

Signed-off-by: James Clark 
Cc: Adrian Hunter 
Cc: Alexander Shishkin 
Cc: Ian Rogers 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: John Garry 
Cc: Leo Yan 
Cc: Mark Rutland 
Cc: Mike Leach 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Suzuki Poulouse 
Cc: Will Deacon 
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: https://lore.kernel.org/r/20230612111403.100613-6-james.clark@arm.com
Signed-off-by: Arnaldo Carvalho de Melo

perf cs-etm: Track exception level

2023-06-12T21:18:13+00:00

Currently we assume all trace belongs to the host machine so when
the decoder should be looking at the guest kernel maps it can crash
because it looks at the host ones instead.

Avoid one scenario (guest kernel running at EL1) by assigning the
default guest machine to this trace. For userspace trace it's still not
possible to determine guest vs host, but the PIDs should help in this
case.

Committer notes:

Fixed up conflict with:

  perf addr_location: Add init/exit/copy functions

That was only on tmp.perf-tools-next.

Reviewed-by: Leo Yan 
Signed-off-by: James Clark 
Cc: Adrian Hunter 
Cc: Alexander Shishkin 
Cc: Ian Rogers 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: John Garry 
Cc: Mark Rutland 
Cc: Mike Leach 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Suzuki Poulouse 
Cc: Will Deacon 
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: https://lore.kernel.org/r/20230612111403.100613-5-james.clark@arm.com
Signed-off-by: Arnaldo Carvalho de Melo

perf cs-etm: Make PID format accessible from struct cs_etm_auxtrace

2023-06-12T21:18:13+00:00

To avoid every user of PID format having to use their own static
local variable, cache it on initialisation and change the accessor to
take struct cs_etm_auxtrace.

Reviewed-by: Leo Yan 
Signed-off-by: James Clark 
Cc: Adrian Hunter 
Cc: Alexander Shishkin 
Cc: Ian Rogers 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: John Garry 
Cc: Mark Rutland 
Cc: Mike Leach 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Suzuki Poulouse 
Cc: Will Deacon 
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: https://lore.kernel.org/r/20230612111403.100613-4-james.clark@arm.com
Signed-off-by: Arnaldo Carvalho de Melo

perf cs-etm: Handle PERF_RECORD_AUX_OUTPUT_HW_ID packet

2023-04-04T12:39:57+00:00

When using dynamically assigned CoreSight trace IDs the drivers can output
the ID / CPU association as a PERF_RECORD_AUX_OUTPUT_HW_ID packet.

Update cs-etm decoder to handle this packet by setting the CPU/Trace ID
mapping.

Reviewed-by: James Clark 
Signed-off-by: Mike Leach 
Acked-by: Suzuki Poulouse 
Cc: Alexander Shishkin 
Cc: Darren Hart 
Cc: Ganapatrao Kulkarni 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: Leo Yan 
Cc: Mark Rutland 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Will Deacon 
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: https://lore.kernel.org/r/20230331055645.26918-2-mike.leach@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo

perf cs-etm: Update decoder code for OpenCSD version 1.4

2023-01-30T17:54:13+00:00

OpenCSD version 1.4 is released with support for FEAT_ITE.

This adds a new packet type, with associated output element ID in the
packet type enum - OCSD_GEN_TRC_ELEM_INSTRUMENTATION.

As we just ignore this packet in perf, add to the switch statement to
avoid the "enum not handled in switch error", but conditionally so as
not to break the perf build for older OpenCSD installations.

Reviewed-by: James Clark 
Signed-off-by: Mike Leach 
Acked-by: Ian Rogers 
Cc: Alexander Shishkin 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: Leo Yan 
Cc: Mark Rutland 
Cc: Mathieu Poirier 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Suzuki Poulouse 
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: https://lore.kernel.org/r/20230120153706.20388-1-mike.leach@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo

perf cs-etm: Ensure that Coresight timestamps don't go backwards

2023-01-22T21:17:46+00:00

There are some edge cases around estimated timestamps that can result
in them going backwards.

One is that after a discontinuity, the last used timestamp is set to 0.
The duration of the next range is then subtracted which could result in
an earlier timestamp than the last instruction. Fix this by not
resetting the last timestamp used on a discontinuity, and make sure that
new estimated timestamps are clamped to be later than that.

Another case is that estimated timestamps could compound over time to
end up being more than the next real timestamp in the trace. Fix this by
clamping the estimates in cs_etm_decoder__do_soft_timestamp() to be no
later than it.

cs_etm_decoder__do_soft_timestamp() also updated next_cs_timestamp,
which meant that the next real timestamp was lost and not stored
anywhere. Fix that by only updating cs_timestamp for estimates and keep
next_cs_timestamp untouched.

Finally, use next_cs_timestamp to signify if a timestamp has been
received previously. Because cs_timestamp has the first range
subtracted, it could technically go to 0 which would break the logic.

Testing
=======

It can be verified that timestamps don't go backwards when tracing on a
single core with the following commands. Across multiple cores it's
expected that timestamps are interleaved:

  $ perf record -e cs_etm/@tmc_etr0/k -C 4 taskset -c 4 sleep 1
  $ perf script --itrace=i1ns --ns -Fcomm,tid,pid,time,cpu,event,ip,sym,addr,symoff,flags,callindent > itrace
  $ sed 's/://g' itrace | awk -F ' ' ' { print $4 } ' | awk '{ if ($1 < prev) { print "line:" NR " " $0 } {prev=$1}}'

Reported-by: Tanmay Jagdale 
Signed-off-by: James Clark 
Acked-by: Suzuki Poulouse 
Tested-by: Tanmay Jagdale 
Cc: Alexander Shishkin 
Cc: Bharat Bhushan 
Cc: George Cherian 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: John Garry 
Cc: Leo Yan 
Cc: Linu Cherian 
Cc: Mark Rutland 
Cc: Mathieu Poirier 
Cc: Mike Leach 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Sunil Kovvuri Goutham 
Cc: Will Deacon 
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: https://lore.kernel.org/r/20230120143702.4035046-9-james.clark@arm.com
Signed-off-by: Arnaldo Carvalho de Melo