On Mon, 2 Dec 2024 08:37:19 +0200
Mike Rapoport <r...@kernel.org> wrote:
> > > On powerpc I get:
> > >
> > > 25850 pages:14 groups: 3
> > > ftrace boot update time = 0 (ns)
> > > ftrace module total update time = 0 (ns)
> >
> > Hmm, does powerpc support "trace_clock_local()" at early boot? I
> > probably can just switch from using "ftrace_now()" to using
> > ktime_get_real_ts64(). Hmm.
>
> The calls to timekeeping_init() and time_init() are after ftrace_init() so
> unless an architecture sets up some clock in setup_arch() like x86 does
> there won't be a clock to use.
Hmm, maybe I should add:
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index be62f0ea1814..362a125d7bcc 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -8588,14 +8588,23 @@ tracing_read_dyn_info(struct file *filp, char __user
*ubuf,
return -ENOMEM;
r = scnprintf(buf, DYN_INFO_BUF_SIZE,
- "%ld pages:%ld groups: %ld\n"
- "ftrace boot update time = %llu (ns)\n"
- "ftrace module total update time = %llu (ns)\n",
+ "%ld pages:%ld groups: %ld\n",
ftrace_update_tot_cnt,
ftrace_number_of_pages,
- ftrace_number_of_groups,
- ftrace_update_time,
- ftrace_total_mod_time);
+ ftrace_number_of_groups);
+
+ if (ftrace_update_time) {
+ r += scnprintf(buf + r, DYN_INFO_BUF_SIZE - r,
+ "ftrace boot update time = %llu (ns)\n",
+ ftrace_update_time);
+ } else {
+ r += scnprintf(buf + r, DYN_INFO_BUF_SIZE - r,
+ "ftrace boot update time = [Unavailable]\n");
+ }
+
+ r += scnprintf(buf + r, DYN_INFO_BUF_SIZE - r,
+ "ftrace module total update time = %llu (ns)\n",
+ ftrace_total_mod_time);
ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
kfree(buf);
Which should turn the above to:
25850 pages:14 groups: 3
ftrace boot update time = [Unavailable]
ftrace module total update time = 0 (ns)
Which should at least make it not confusing.
I'm assuming that the module timings are zero because no modules were loaded?
-- Steve
