linux.git/tools/perf/tests/shell/coresight, branch master

perf test: Add Arm CoreSight callchain test

2026-07-03T23:52:00+00:00

Add a CoreSight shell test for synthesized callchains.

The test uses the new callchain workload to generate trace and decodes
it with synthesis callchain. It then verifies that the instruction
samples show the expected callchain push and pop.

Use control FIFOs so tracing starts only around the workload, which
keeps the trace data small. The test is limited to with the cs_etm
event available and root permission.

After:

  perf test 138 -vvv
  138: CoreSight synthesized callchain:
  ---- start ----
  test child forked, pid 35581
  Callchain flow matched:
    l1=4642868 l2=4642880 l3=4642895 l4=4642919 l5=4670494 l6=4670500 l7=4670520
  ---- end(0) ----
  138: CoreSight synthesized callchain                                                                           : Ok

Assisted-by: Codex:GPT-5.5
Reviewed-by: James Clark 
Signed-off-by: Leo Yan 
Signed-off-by: Namhyung Kim

perf cs-etm: Filter synthesized branch samples

2026-07-03T23:51:59+00:00

The itrace 'c' and 'r' options request synthesized branch events for
calls and returns only. For perf script the default itrace options are
"--itrace=ce", so CS ETM should emit call branches and error events by
default.

CS ETM currently synthesizes a branch sample for every decoded taken
branch whenever branch synthesis is enabled. This produces redundant
jump and conditional branch samples.

Add a branch filter derived from the itrace calls and returns options.
When neither option is set, keep the existing behavior and synthesize all
branch samples. When calls or returns are requested, emit only branch
samples whose flags match the selected branch type, while preserving trace
begin/end markers.

Also update test_arm_coresight_disasm.sh and arm-cs-trace-disasm.py
to use the --itrace=b option for generating branch samples.

Before:

  perf script -F,+flags

  callchain_test    6114 [005] 331519.825214:          1 branches:   tr strt jmp                           0 [unknown] ([unknown]) => ffff8000803a3a68 perf_report_aux_output_id+0x50 ([kernel.kallsyms])
  callchain_test    6114 [005] 331519.825214:          1 branches:   call                   ffff8000803a3a74 perf_report_aux_output_id+0x5c ([kernel.kallsyms]) => ffff8000817f4d88 memset+0x0 ([kernel.kallsyms])
  callchain_test    6114 [005] 331519.825214:          1 branches:   jmp                    ffff8000817f4d8c memset+0x4 ([kernel.kallsyms]) => ffff8000817f4c00 __pi_memset_generic+0x0 ([kernel.kallsyms])
  callchain_test    6114 [005] 331519.825214:          1 branches:   jcc                    ffff8000817f4c1c __pi_memset_generic+0x1c ([kernel.kallsyms]) => ffff8000817f4c44 __pi_memset_generic+0x44 ([kernel.kallsyms])
  callchain_test    6114 [005] 331519.825214:          1 branches:   jcc                    ffff8000817f4c4c __pi_memset_generic+0x4c ([kernel.kallsyms]) => ffff8000817f4c5c __pi_memset_generic+0x5c ([kernel.kallsyms])
  callchain_test    6114 [005] 331519.825214:          1 branches:   jcc                    ffff8000817f4c5c __pi_memset_generic+0x5c ([kernel.kallsyms]) => ffff8000817f4cf0 __pi_memset_generic+0xf0 ([kernel.kallsyms])
  callchain_test    6114 [005] 331519.825214:          1 branches:   jcc                    ffff8000817f4d30 __pi_memset_generic+0x130 ([kernel.kallsyms]) => ffff8000817f4d68 __pi_memset_generic+0x168 ([kernel.kallsyms])
  callchain_test    6114 [005] 331519.825214:          1 branches:   jcc                    ffff8000817f4d78 __pi_memset_generic+0x178 ([kernel.kallsyms]) => ffff8000817f4d6c __pi_memset_generic+0x16c ([kernel.kallsyms])
  callchain_test    6114 [005] 331519.825214:          1 branches:   jcc                    ffff8000817f4d78 __pi_memset_generic+0x178 ([kernel.kallsyms]) => ffff8000817f4d6c __pi_memset_generic+0x16c ([kernel.kallsyms])
  callchain_test    6114 [005] 331519.825214:          1 branches:   jcc                    ffff8000817f4d78 __pi_memset_generic+0x178 ([kernel.kallsyms]) => ffff8000817f4d6c __pi_memset_generic+0x16c ([kernel.kallsyms])
  callchain_test    6114 [005] 331519.825214:          1 branches:   return                 ffff8000817f4d84 __pi_memset_generic+0x184 ([kernel.kallsyms]) => ffff8000803a3a78 perf_report_aux_output_id+0x60 ([kernel.kallsyms])
  callchain_test    6114 [005] 331519.825214:          1 branches:   jcc                    ffff8000803a3a98 perf_report_aux_output_id+0x80 ([kernel.kallsyms]) => ffff8000803a3b04 perf_report_aux_output_id+0xec ([kernel.kallsyms])
  callchain_test    6114 [005] 331519.825214:          1 branches:   call                   ffff8000803a3b1c perf_report_aux_output_id+0x104 ([kernel.kallsyms]) => ffff8000803a38f8 __perf_event_header__init_id+0x0 ([kernel.kallsyms])

After:

  callchain_test    6114 [005] 331519.825214:          1 branches:   tr strt jmp                           0 [unknown] ([unknown]) => ffff8000803a3a68 perf_report_aux_output_id+0x50 ([kernel.kallsyms])
  callchain_test    6114 [005] 331519.825214:          1 branches:   call                   ffff8000803a3a74 perf_report_aux_output_id+0x5c ([kernel.kallsyms]) => ffff8000817f4d88 memset+0x0 ([kernel.kallsyms])
  callchain_test    6114 [005] 331519.825214:          1 branches:   call                   ffff8000803a3b1c perf_report_aux_output_id+0x104 ([kernel.kallsyms]) => ffff8000803a38f8 __perf_event_header__init_id+0x0 ([kernel.kallsyms])
  callchain_test    6114 [005] 331519.825214:          1 branches:   call                   ffff8000803a39c0 __perf_event_header__init_id+0xc8 ([kernel.kallsyms]) => ffff800080105258 __task_pid_nr_ns+0x0 ([kernel.kallsyms])
  callchain_test    6114 [005] 331519.825214:          1 branches:   call                   ffff80008010528c __task_pid_nr_ns+0x34 ([kernel.kallsyms]) => ffff8000801d5610 __rcu_read_lock+0x0 ([kernel.kallsyms])
  callchain_test    6114 [005] 331519.825214:          1 branches:   call                   ffff8000801052b0 __task_pid_nr_ns+0x58 ([kernel.kallsyms]) => ffff800080192078 lock_acquire+0x0 ([kernel.kallsyms])
  callchain_test    6114 [005] 331519.825214:          1 branches:   call                   ffff8000801923f4 lock_acquire+0x37c ([kernel.kallsyms]) => ffff8000801d6da0 rcu_is_watching+0x0 ([kernel.kallsyms])

Fixes: b12235b113cf ("perf tools: Add mechanic to synthesise CoreSight trace packets")
Signed-off-by: Leo Yan 
Reviewed-by: James Clark 
Signed-off-by: Leo Yan 
Signed-off-by: Namhyung Kim

perf test cs-etm: Move existing tests to coresight folder

2026-06-10T21:55:49+00:00

There is a subfolder for Coresight tests so might as well keep them all
in here.

Reviewed-by: Leo Yan 
Signed-off-by: James Clark 
Cc: Amir Ayupov 
Cc: Ian Rogers 
Cc: Jiri Olsa 
Cc: Jonathan Corbet 
Cc: Mike Leach 
Cc: Namhyung Kim 
Cc: Paschalis Mpeis 
Cc: Shuah Khan 
Cc: Suzuki Poulouse 
Signed-off-by: Arnaldo Carvalho de Melo

perf test cs-etm: Remove unused Coresight workloads

2026-06-10T21:55:49+00:00

These are now unused and had various issues like not working with out of
source builds and being slow to compile. Delete them.

Signed-off-by: James Clark 
Tested-by: Leo Yan 
Cc: Amir Ayupov 
Cc: Ian Rogers 
Cc: Jiri Olsa 
Cc: Jonathan Corbet 
Cc: Mike Leach 
Cc: Namhyung Kim 
Cc: Paschalis Mpeis 
Cc: Shuah Khan 
Cc: Suzuki Poulouse 
Signed-off-by: Arnaldo Carvalho de Melo

perf test cs-etm: Test decoding for concurrent threads test

2026-06-10T21:55:49+00:00

The thread_loop test only looks for context IDs in the raw trace.
There's a lot more that can go wrong when decoding these, so replace it
with a test that looks at the final output for matching thread names and
symbols.

In the future we might use timestamps and context switch events to track
threads, so looking at context IDs in the raw trace wouldn't always
work.

Reviewed-by: Leo Yan 
Signed-off-by: James Clark 
Tested-by: Leo Yan 
Cc: Amir Ayupov 
Cc: Ian Rogers 
Cc: Jiri Olsa 
Cc: Jonathan Corbet 
Cc: Mike Leach 
Cc: Namhyung Kim 
Cc: Paschalis Mpeis 
Cc: Shuah Khan 
Cc: Suzuki Poulouse 
Signed-off-by: Arnaldo Carvalho de Melo

perf test cs-etm: Replace memcpy test with raw dump stress test

2026-06-10T21:55:49+00:00

Like asm_pure_loop, this memcpy test only checks that 10 of each of a
few trace packet types occur after recording a lot of trace, which isn't
more specific than other existing Coresight tests.

Assume it was supposed to be a stress test for dumping and replace it
with one that doesn't require a custom binary and checks for a specific
amount of raw output. Don't bother checking for packets because the
other tests that test decoding will catch issues with malformed data.

This also adds coverage for exit snapshot mode which was missing.

Signed-off-by: James Clark 
Tested-by: Leo Yan 
Cc: Amir Ayupov 
Cc: Ian Rogers 
Cc: Jiri Olsa 
Cc: Jonathan Corbet 
Cc: Mike Leach 
Cc: Namhyung Kim 
Cc: Paschalis Mpeis 
Cc: Shuah Khan 
Cc: Suzuki Poulouse 
Signed-off-by: Arnaldo Carvalho de Melo

perf test cs-etm: Remove asm_pure_loop test

2026-06-10T21:55:48+00:00

It's not obvious what this test is for so remove it. It's not a stress
test because it doesn't output lots of data and it's not a functional
test because it only looks for raw trace output. It seems to imply that
a program written in assembly influences whether trace would be
generated by the CPU or not, but the CPU doesn't know what language the
program is written in.

We already have lots of Coresight tests that test the full pipeline
including decoding, and in many more modes of operation than this one,
so if no trace was collected they will already fail leaving this one
redundant.

Reviewed-by: Leo Yan 
Signed-off-by: James Clark 
Cc: Amir Ayupov 
Cc: Ian Rogers 
Cc: Jiri Olsa 
Cc: Jonathan Corbet 
Cc: Mike Leach 
Cc: Namhyung Kim 
Cc: Paschalis Mpeis 
Cc: Shuah Khan 
Cc: Suzuki Poulouse 
Signed-off-by: Arnaldo Carvalho de Melo

perf test cs-etm: Replace unroll loop thread with deterministic decode test

2026-06-10T21:55:48+00:00

Testing a long sequence without branches seems like it would be better
as a decoder unit test, and this test doesn't test decoding either, so
it's not clear what bugs this is trying to catch.

The new deterministic workload has somewhat long sequences when built
unoptimized, and we can always increase them later if we want to. But
now we test that decoding always gives the same result for the same
sequence of code which we've never had before.

Signed-off-by: James Clark 
Tested-by: Leo Yan 
Cc: Amir Ayupov 
Cc: Ian Rogers 
Cc: Jiri Olsa 
Cc: Jonathan Corbet 
Cc: Mike Leach 
Cc: Namhyung Kim 
Cc: Paschalis Mpeis 
Cc: Shuah Khan 
Cc: Suzuki Poulouse 
Signed-off-by: Arnaldo Carvalho de Melo

perf test cs-etm: Test process attribution

2026-06-10T21:55:48+00:00

Run the context switch workload on one CPU and trace it to test that
symbols are attributed to the correct process and that the attribution
changes at the exact point that the context switch happened.

Reviewed-by: Leo Yan 
Signed-off-by: James Clark 
Cc: Amir Ayupov 
Cc: Ian Rogers 
Cc: Jiri Olsa 
Cc: Jonathan Corbet 
Cc: Mike Leach 
Cc: Namhyung Kim 
Cc: Paschalis Mpeis 
Cc: Shuah Khan 
Cc: Suzuki Poulouse 
Signed-off-by: Arnaldo Carvalho de Melo

perf test coresight: Dismiss clang warning for unroll loop thread

2025-10-06T19:49:25+00:00

clang-18.1.3 on Ubuntu 24.04.2 reports warning:

  unroll_loop_thread.c:35:25: warning: value size does not match register size specified by the constraint and modifier [-Wasm-operand-widths]
     35 |                         : /* in */ [in] "r" (in)
        |                                              ^
  unroll_loop_thread.c:39:1: warning: non-void function does not return a value [-Wreturn-type]
     39 | }
        | ^

Use the modifier "w" for 32-bit register access and return NULL at the
end of thread function.

Signed-off-by: Leo Yan 
Reviewed-by: Ian Rogers 
Link: https://lore.kernel.org/r/20251006-perf_build_android_ndk-v3-7-4305590795b2@arm.com
Cc: Palmer Dabbelt 
Cc: Albert Ou 
Cc: Alexandre Ghiti 
Cc: Nick Desaulniers 
Cc: Justin Stitt 
Cc: Bill Wendling 
Cc: Adrian Hunter 
Cc: Arnaldo Carvalho de Melo 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Nathan Chancellor 
Cc: James Clark 
Cc: linux-riscv@lists.infradead.org
Cc: llvm@lists.linux.dev
Cc: Paul Walmsley 
Cc: linux-kernel@vger.kernel.org
Cc: linux-perf-users@vger.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo