Previously, trace record files (created by st_set_trace_file_enabled(true)) were created by the simple backend at initialization time, even if no events were actually enabled.
As a consequence, the working directory would become littered with trace-PID files just by enabling the simple backend at configure time, even when no -trace options were used. --- I've been using this to avoid creation of empty trace record files. I haven't done any scientific performance studies, but an extra function call/conditional/return when recording every trace event doesn't seem to have any noticeable effect. Signed-off-by: Hollis Blanchard <hollis_blanch...@mentor.com> --- trace/simple.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/trace/simple.c b/trace/simple.c index 3fdcc82..67ccc3c 100644 --- a/trace/simple.c +++ b/trace/simple.c @@ -209,6 +209,8 @@ int trace_record_start(TraceBufferRecord *rec, TraceEventID event, size_t datasi uint64_t event_u64 = event; uint64_t timestamp_ns = get_clock(); + st_set_trace_file_enabled(true); + do { old_idx = g_atomic_int_get(&trace_idx); smp_rmb(); @@ -320,6 +322,7 @@ void st_set_trace_file_enabled(bool enable) */ void st_set_trace_file(const char *file) { + /* Tracing will be re-enabled when the next event is written. */ st_set_trace_file_enabled(false); g_free(trace_file_name); @@ -330,8 +333,6 @@ void st_set_trace_file(const char *file) } else { trace_file_name = g_strdup_printf("%s", file); } - - st_set_trace_file_enabled(true); } void st_print_trace_file_status(FILE *stream, int (*stream_printf)(FILE *stream, const char *fmt, ...)) -- 1.9.1