[PATCH v4 0/3] perf test: Per-test timeouts, JUnit XML compliance, and snippet improvements

[Ian Rogers <irogers@google.com>]

This series adds per-test timeout support to 'perf test', improves JUnit
XML output to validate against strict JUnit schemas, and refines the
verbose=1 failure snippet output when tests fail with a signal or time
out:

1. Add a per-test timeout (default 60s, configurable via '-t'/'--timeout',
   0 to disable, disabled with '-F'/'--dont-fork'). Forked tests run in
   their own process groups and the existing polling loops in
   finish_test() and finish_tests_parallel() check elapsed runtimes,
   sending SIGTERM on timeout and escalating to SIGKILL after 1 second.
   Timed out tests are reported as 'TIMEOUT!', listed in the summary,
   and recorded as '<error message="TIMEOUT" type="timeout">' in JUnit
   XML output.

2. Update 'perf test -j' output to validate cleanly against both the
   Apache Ant/Windy Road JUnit schema (JUnit.xsd) and the Jenkins
   xUnit/Maven Surefire schema (junit-10.xsd), including required
   '<testsuite>' attributes, '<properties>' from uname, '<system-out/>'
   and '<system-err/>', self-closing tags, apostrophe escaping, and
   UTF-8/XML 1.0 codepoint validation.

3. Improve verbose=1 failure snippet selection in
   print_test_failure_snippet() to skip blank and stack trace lines
   when selecting context and scanning backwards from the end of the
   log, and prioritize the test output line immediately preceding
   '---- unexpected signal' so trailing test progress is shown instead
   of outermost stack frames.

v4:
 - Drop the ITIMER_REAL timer and SIGALRM handler in patch 1, relying on
   the existing 10ms/100ms polling loops in finish_test() and
   finish_tests_parallel() to detect timeouts.
 - Only fall back to kill(pid, sig) when kill(-pid, sig) fails, and
   ignore SIGTERM/SIGINT while waiting for subprocesses in
   run_test_child().
 - Add patch 3 to avoid stack trace noise in verbose=1 failure snippets.

v3:
 - Block SIGINT/SIGTERM while a test process may be reaped and until its
   pid is cleared, and skip already reaped tests in the signal path.

v2:
 - Reset SIGALRM to SIG_DFL in the forked test child.
 - Replace the blocking waitpid(-1) loop with a bounded, non-blocking
   wait that only runs when interrupted by SIGTERM/SIGINT.
 - Ensure the SIGKILL escalation reaches the whole process group before
   the zombie is reaped.
 - Factor out timespec_diff_secs() and TEST_KILL_GRACE_SECS.

Ian Rogers (3):
  perf test: Add per-test timeout support
  perf test: Improve JUnit XML schema compliance and completeness
  perf test: Avoid stack trace noise in verbose=1 failure snippets

 tools/perf/Documentation/perf-test.txt |  12 +-
 tools/perf/tests/builtin-test.c        | 668 +++++++++++++++++++------
 tools/perf/tests/tests.h               |   7 +-
 3 files changed, 543 insertions(+), 144 deletions(-)

-- 
2.56.0.385.gd3acb90ef8-goog