This adds an option '-b/--buffer-size' to allow us set the size of per-cpu tracing buffer.
Signed-off-by: Changbin Du <[email protected]> --- tools/perf/builtin-ftrace.c | 45 ++++++++++++++++++++++++++++--------- 1 file changed, 35 insertions(+), 10 deletions(-) diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c index 8fd95c109fe8..a93fbdac6aa4 100644 --- a/tools/perf/builtin-ftrace.c +++ b/tools/perf/builtin-ftrace.c @@ -47,6 +47,7 @@ struct perf_ftrace { bool long_info; unsigned tracing_thresh; bool trace_children; + unsigned buffer_size_kb; }; struct filter_entry { @@ -187,6 +188,17 @@ static int read_tracing_file_to_stdout(const char *name) return ret; } +static int write_tracing_file_int(const char *name, int value) +{ + char buf[16]; + + snprintf(buf, sizeof(buf), "%d", value); + if (write_tracing_file(name, buf) < 0) + return -1; + + return 0; +} + static int reset_tracing_cpu(void); static void reset_tracing_filters(void); @@ -360,8 +372,6 @@ static void reset_tracing_filters(void) static int set_tracing_depth(struct perf_ftrace *ftrace) { - char buf[16]; - if (ftrace->graph_depth == 0) return 0; @@ -370,9 +380,7 @@ static int set_tracing_depth(struct perf_ftrace *ftrace) return -1; } - snprintf(buf, sizeof(buf), "%d", ftrace->graph_depth); - - if (write_tracing_file("max_graph_depth", buf) < 0) + if (write_tracing_file_int("max_graph_depth", ftrace->graph_depth) < 0) return -1; return 0; @@ -419,14 +427,10 @@ static int set_tracing_long_info(struct perf_ftrace *ftrace) static int set_tracing_thresh(struct perf_ftrace *ftrace) { - char buf[16]; - if (ftrace->tracing_thresh == 0) return 0; - snprintf(buf, sizeof(buf), "%d", ftrace->tracing_thresh); - - if (write_tracing_file("tracing_thresh", buf) < 0) + if (write_tracing_file_int("tracing_thresh", ftrace->tracing_thresh) < 0) return -1; return 0; @@ -454,6 +458,20 @@ static int set_tracing_trace_children(struct perf_ftrace *ftrace) return 0; } +static int set_tracing_buffer_size_kb(struct perf_ftrace *ftrace) +{ + int ret; + + if (ftrace->buffer_size_kb == 0) + return 0; + + ret = write_tracing_file_int("buffer_size_kb", ftrace->buffer_size_kb); + if (ret < 0) + return ret; + + return 0; +} + static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv) { char *trace_file; @@ -557,6 +575,11 @@ static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv) goto out_reset; } + if (set_tracing_buffer_size_kb(ftrace) < 0) { + pr_err("failed to set tracing per-cpu buffer size\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; @@ -706,6 +729,8 @@ int cmd_ftrace(int argc, const char **argv) "Only show functions of which the duration is greater than <n>µs"), OPT_BOOLEAN(0, "trace-children", &ftrace.trace_children, "Trace children processes"), + OPT_UINTEGER('b', "buffer-size", &ftrace.buffer_size_kb, + "size of per cpu buffer in kb"), OPT_END() }; -- 2.25.1
