From: Ian Rogers Date: Tue, 2 Jun 2026 17:41:20 +0000 (-0700) Subject: perf test: Show snippet failure output for verbose=1 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=b5a4a361f5cfb8f6f6f0a59536fd5fad11ed9f5f;p=thirdparty%2Fkernel%2Flinux.git perf test: Show snippet failure output for verbose=1 Currently, when running tests in verbose mode (-v), if a test case fails, the entire raw standard error buffer is dumped to stderr via fprintf(stderr, "%s", child->err_output.buf). For tests that generate massive amounts of debugging or logging output before dying, this results in multi-page terminal dumps where highly critical diagnostic keywords (error, fail, segv) are easily lost. Implement a smart, bounded snippet string processor to improve failure triaging: 1. Introduce a configurable quota limit static unsigned int failure_snippet_lines = 10; accessible via a new command-line option --failure-snippet-lines . 2. Parse the raw error buffer dynamically into lines and run a three-pass extraction algorithm: - Pass 0: Always select the very first line of the log as an initial outline marker. - Pass 1: Scan forward from the top of the log to pick up to N lines that contain case-insensitive failure keywords (error, fail, segv, abort) to isolate the root cause. Automatically pull in the immediate subsequent line as highly-prioritized context. Allow adjacent matching lines to overlap without dropping context by evaluating keywords for all lines (e.g. when "Failed to report" is followed by "Error:"). - Pass 2: If quota remains, scan backward from the absolute tail of the log to capture trailing crash or abort context. 3. Output the selected lines in their original chronological order, inserting a clear ... separator between non-contiguous line jumps. 4. Wrap matched failure keywords dynamically in bold red (PERF_COLOR_RED) to immediately draw the eye to failures. 5. Invoke the smart processor purely when verbose == 1 && ret == TEST_FAIL in both finish_test and finish_tests_parallel, leaving raw full-output dumping completely untouched when running highly verbose (-vv). Assisted-by: Gemini-CLI:Google Gemini 3 Signed-off-by: Ian Rogers Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Namhyung Kim Cc: Peter Zijlstra Signed-off-by: Arnaldo Carvalho de Melo --- diff --git a/tools/perf/tests/builtin-test.c b/tools/perf/tests/builtin-test.c index 0479184c3dda3..3401d79a1d24a 100644 --- a/tools/perf/tests/builtin-test.c +++ b/tools/perf/tests/builtin-test.c @@ -48,6 +48,8 @@ static bool dont_fork; static bool sequential; /* Number of times each test is run. */ static unsigned int runs_per_test = 1; +/* Number of lines to include in failure snippet. */ +static unsigned int failure_snippet_lines = 10; const char *dso_to_test; const char *test_objdump_path = "objdump"; @@ -344,7 +346,7 @@ static int run_test_child(struct child_process *process) for (size_t i = 0; i < ARRAY_SIZE(signals); i++) signal(signals[i], child_test_sig_handler); - pr_debug("--- start ---\n"); + pr_debug("---- start ----\n"); pr_debug("test child forked, pid %d\n", getpid()); err = test_function(child->test, child->test_case_num)(child->test, child->test_case_num); pr_debug("---- end(%d) ----\n", err); @@ -400,6 +402,195 @@ static int print_test_result(struct test_suite *t, int curr_suite, int curr_test return 0; } +static const char * const fail_keywords[] = { + "error", "fail", "segv", "abort", + "signal", "fatal", "panic", "corrupt", NULL +}; + +static const char *find_next_keyword(const char *str, size_t max_len, size_t *kw_len) +{ + const char *best = NULL; + size_t best_len = 0; + int k; + + for (k = 0; fail_keywords[k]; k++) { + const char *s = str; + size_t len = strlen(fail_keywords[k]); + + while ((size_t)(s - str) + len <= max_len) { + size_t i; + + if (best && s >= best) + break; + + for (i = 0; i < len; i++) { + if (tolower(s[i]) != fail_keywords[k][i]) + break; + } + if (i == len) { + if (!best || s < best) { + best = s; + best_len = len; + } + break; + } + s++; + } + } + if (best) { + *kw_len = best_len; + return best; + } + return NULL; +} + +static void print_line_highlighted(FILE *fp, const char *line, size_t len) +{ + const char *s = line; + + while (len > 0) { + size_t kw_len = 0; + const char *match = find_next_keyword(s, len, &kw_len); + + if (!match) { + fwrite(s, 1, len, fp); + break; + } + if (match > s) + fwrite(s, 1, match - s, fp); + if (perf_use_color_default) + fprintf(fp, "%s", PERF_COLOR_RED); + fwrite(match, 1, kw_len, fp); + if (perf_use_color_default) + fprintf(fp, "%s", PERF_COLOR_RESET); + + len -= (match + kw_len) - s; + s = match + kw_len; + } +} + + +static void print_test_failure_snippet(FILE *fp, const char *buf) +{ + size_t num_lines = 0; + size_t max_lines = 128; + const char **lines = calloc(max_lines, sizeof(const char *)); + size_t *line_lens = calloc(max_lines, sizeof(size_t)); + const char *s = buf; + size_t i; + unsigned int picked_count = 0; + bool *pick; + int last_printed = -1; + + if (!lines || !line_lens) { + free(lines); free(line_lens); + fprintf(fp, "%s", buf); + return; + } + + while (*s) { + const char *eol = strchr(s, '\n'); + size_t len; + + if (eol) + len = eol - s + 1; + else + len = strlen(s); + + if (num_lines == max_lines) { + const char **new_lines; + size_t *new_lens; + + max_lines *= 2; + new_lines = realloc(lines, max_lines * sizeof(const char *)); + if (!new_lines) { + free(lines); free(line_lens); + fprintf(fp, "%s", buf); + return; + } + lines = new_lines; + + new_lens = realloc(line_lens, max_lines * sizeof(size_t)); + if (!new_lens) { + free(lines); free(line_lens); + fprintf(fp, "%s", buf); + return; + } + line_lens = new_lens; + } + lines[num_lines] = s; + line_lens[num_lines] = len; + num_lines++; + s += len; + } + + if (num_lines <= failure_snippet_lines) { + for (i = 0; i < num_lines; i++) + print_line_highlighted(fp, lines[i], line_lens[i]); + free(lines); free(line_lens); + return; + } + + pick = calloc(num_lines, sizeof(bool)); + if (!pick) { + for (i = 0; i < num_lines; i++) + print_line_highlighted(fp, lines[i], line_lens[i]); + free(lines); free(line_lens); + return; + } + + /* Pass 0: Always pick the very first line */ + if (num_lines > 0 && picked_count < failure_snippet_lines) { + pick[0] = true; + picked_count++; + } + + /* Pass 1: Pick lines with failure keywords from start (Highest Priority) */ + for (i = 0; i < num_lines && picked_count < failure_snippet_lines; i++) { + size_t dummy; + + if (find_next_keyword(lines[i], line_lens[i], &dummy)) { + if (!pick[i]) { + pick[i] = true; + picked_count++; + } + /* Prioritize getting the immediate next line for context */ + if (i + 1 < num_lines && !pick[i + 1] && + picked_count < failure_snippet_lines) { + pick[i + 1] = true; + picked_count++; + } + } + } + + /* Pass 2: Fill remaining quota from the end backwards */ + i = num_lines; + while (i > 0 && picked_count < failure_snippet_lines) { + i--; + if (!pick[i]) { + pick[i] = true; + picked_count++; + } + } + + for (i = 0; i < num_lines; i++) { + if (!pick[i]) + continue; + if (last_printed != -1 && (int)i > last_printed + 1) { + if (perf_use_color_default) + fprintf(fp, "%s...%s\n", PERF_COLOR_BLUE, PERF_COLOR_RESET); + else + fprintf(fp, "...\n"); + } + print_line_highlighted(fp, lines[i], line_lens[i]); + last_printed = i; + } + + free(pick); + free(lines); + free(line_lens); +} + static void finish_test(struct child_test **child_tests, int running_test, int child_test_num, int width) { @@ -518,8 +709,10 @@ static void finish_test(struct child_test **child_tests, int running_test, int c strbuf_release(&err_output); err_output = merged; } - if (verbose > 1 || (verbose == 1 && ret == TEST_FAIL)) + if (verbose > 1) fprintf(stderr, "%s", err_output.buf); + else if (verbose == 1 && ret == TEST_FAIL) + print_test_failure_snippet(stderr, err_output.buf); strbuf_release(&err_output); strbuf_release(&child_test->err_output); @@ -731,8 +924,10 @@ static int finish_tests_parallel(struct child_test **child_tests, size_t num_tes } } - if (verbose > 1 || (verbose == 1 && child->result == TEST_FAIL)) + if (verbose > 1) fprintf(stderr, "%s", child->err_output.buf); + else if (verbose == 1 && child->result == TEST_FAIL) + print_test_failure_snippet(stderr, child->err_output.buf); print_test_result(child->test, child->suite_num, child->test_case_num, child->result, width, 0); @@ -1075,6 +1270,8 @@ int cmd_test(int argc, const char **argv) OPT_STRING(0, "dso", &dso_to_test, "dso", "dso to test"), OPT_STRING(0, "objdump", &test_objdump_path, "path", "objdump binary to use for disassembly and annotations"), + OPT_UINTEGER(0, "failure-snippet-lines", &failure_snippet_lines, + "Number of lines to include in failure snippet, default 10"), OPT_END() }; const char * const test_subcommands[] = { "list", NULL };