trace2: add trace2_child_ready() to report on background children
Create "child_ready" event to capture the state of a child process
created in the background.
When a child command is started a "child_start" event is generated in
the Trace2 log. For normal synchronous children, a "child_exit" event
is later generated when the child exits or is terminated. The two events
include information, such as the "child_id" and "pid", to allow post
analysis to match-up the command line and exit status.
When a child is started in the background (and may outlive the parent
process), it is not possible for the parent to emit a "child_exit"
event. Create a new "child_ready" event to indicate whether the
child was successfully started. Also include the "child_id" and "pid"
to allow similar post processing.
This will be used in a later commit with the new "start_bg_command()".
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/trace2/tr2_tgt_perf.c b/trace2/tr2_tgt_perf.c
index af4d65a..e4acca1 100644
--- a/trace2/tr2_tgt_perf.c
+++ b/trace2/tr2_tgt_perf.c
@@ -360,6 +360,20 @@ static void fn_child_exit_fl(const char *file, int line,
strbuf_release(&buf_payload);
}
+static void fn_child_ready_fl(const char *file, int line,
+ uint64_t us_elapsed_absolute, int cid, int pid,
+ const char *ready, uint64_t us_elapsed_child)
+{
+ const char *event_name = "child_ready";
+ struct strbuf buf_payload = STRBUF_INIT;
+
+ strbuf_addf(&buf_payload, "[ch%d] pid:%d ready:%s", cid, pid, ready);
+
+ perf_io_write_fl(file, line, event_name, NULL, &us_elapsed_absolute,
+ &us_elapsed_child, NULL, &buf_payload);
+ strbuf_release(&buf_payload);
+}
+
static void fn_thread_start_fl(const char *file, int line,
uint64_t us_elapsed_absolute)
{
@@ -553,6 +567,7 @@ struct tr2_tgt tr2_tgt_perf = {
fn_alias_fl,
fn_child_start_fl,
fn_child_exit_fl,
+ fn_child_ready_fl,
fn_thread_start_fl,
fn_thread_exit_fl,
fn_exec_fl,
