From 5b34747238686021a39495f7ae0bfadc27fe3e83 Mon Sep 17 00:00:00 2001 From: Changbin Du Date: Sat, 8 Aug 2020 10:31:29 +0800 Subject: [PATCH] perf ftrace: Add option '--inherit' to trace children processes This adds an option '--inherit' to allow us trace children processes spawned by our target. Signed-off-by: Changbin Du Acked-by: Namhyung Kim Cc: Jiri Olsa Cc: Peter Zijlstra Cc: Steven Rostedt (VMware) Link: http://lore.kernel.org/lkml/20200808023141.14227-7-changbin.du@gmail.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/Documentation/perf-ftrace.txt | 3 +++ tools/perf/builtin-ftrace.c | 38 ++++++++++++++++++++++++++++++++ 2 files changed, 41 insertions(+) diff --git a/tools/perf/Documentation/perf-ftrace.txt b/tools/perf/Documentation/perf-ftrace.txt index 7a5d915..c46d0a0 100644 --- a/tools/perf/Documentation/perf-ftrace.txt +++ b/tools/perf/Documentation/perf-ftrace.txt @@ -58,6 +58,9 @@ OPTIONS Set the size of per-cpu tracing buffer, is expected to be a number with appended unit character - B/K/M/G. +--inherit:: + Trace children processes spawned by our target. + -T:: --trace-funcs=:: Select function tracer and set function filter on the given diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c index 39c694b..07b81d0 100644 --- a/tools/perf/builtin-ftrace.c +++ b/tools/perf/builtin-ftrace.c @@ -41,6 +41,7 @@ struct perf_ftrace { struct list_head nograph_funcs; int graph_depth; unsigned long percpu_buffer_size; + bool inherit; }; struct filter_entry { @@ -182,9 +183,27 @@ static int write_tracing_file_int(const char *name, int value) return 0; } +static int write_tracing_option_file(const char *name, const char *val) +{ + char *file; + int ret; + + if (asprintf(&file, "options/%s", name) < 0) + return -1; + + ret = __write_tracing_file(file, val, false); + free(file); + return ret; +} + static int reset_tracing_cpu(void); static void reset_tracing_filters(void); +static void reset_tracing_options(struct perf_ftrace *ftrace __maybe_unused) +{ + write_tracing_option_file("function-fork", "0"); +} + static int reset_tracing_files(struct perf_ftrace *ftrace __maybe_unused) { if (write_tracing_file("tracing_on", "0") < 0) @@ -203,6 +222,7 @@ static int reset_tracing_files(struct perf_ftrace *ftrace __maybe_unused) return -1; reset_tracing_filters(); + reset_tracing_options(ftrace); return 0; } @@ -341,6 +361,17 @@ static int set_tracing_percpu_buffer_size(struct perf_ftrace *ftrace) return 0; } +static int set_tracing_trace_inherit(struct perf_ftrace *ftrace) +{ + if (!ftrace->inherit) + return 0; + + if (write_tracing_option_file("function-fork", "1") < 0) + return -1; + + return 0; +} + static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv) { char *trace_file; @@ -410,6 +441,11 @@ static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv) goto out_reset; } + if (set_tracing_trace_inherit(ftrace) < 0) { + pr_err("failed to set tracing option function-fork\n"); + goto out_reset; + } + if (write_tracing_file("current_tracer", ftrace->tracer) < 0) { pr_err("failed to set current_tracer to %s\n", ftrace->tracer); goto out_reset; @@ -618,6 +654,8 @@ int cmd_ftrace(int argc, const char **argv) "Max depth for function graph tracer"), OPT_CALLBACK('m', "buffer-size", &ftrace.percpu_buffer_size, "size", "size of per cpu buffer", parse_buffer_size), + OPT_BOOLEAN(0, "inherit", &ftrace.inherit, + "trace children processes"), OPT_END() }; -- 2.7.4