# Re: \[PATCH 1/3\] printk: Release console\_sem after logbuf\_lock

- From: Ingo Molnar \<hidden\>
- Date: 2011-06-10 12:34:46 
- List: linux-fbdev
- Page: https://ratatoskr.run/linux-fbdev/2011/06/3727842
- Thread: https://ratatoskr.run/linux-fbdev/2011/06/3727840/t.md

```text

* Peter Zijlstra [ref] wrote:

> thinking that that would have my printk stmts appear on both the 
> fbcon as well as the serial line. But they fail to appear on the 
> latency tracer (current max was 165us waking an idle cpu).

Have you removed this bit:

                spin_unlock(&logbuf_lock);
                stop_critical_timings();        /* don't trace print latency */
                call_console_drivers(_con_start, _log_end);
                start_critical_timings();
                local_irq_restore(flags);

which hides the latencies from the latency tracer?

Thanks,

	Ingo
```