Re: [RCU] rcu_tasks_trace_qs(): trc_reader_special.b.need_qs value incorrect likely()?

From: Steven Rostedt
Date: Sat Dec 02 2023 - 18:49:42 EST


On Sat, 2 Dec 2023 14:24:26 -0800
"Paul E. McKenney" <paulmck@xxxxxxxxxx> wrote:

> > Note, the unlikely tracing is running on my production server v6.6.3.
> >
> > The above trace is from my test box with latest Linus's tree.
>
> Nice tool!!!

Thanks! It's only been in the kernel since 2008 ;-)

1f0d69a9fc815 ("tracing: profile likely and unlikely annotations")

>
> My kneejerk reaction is that that condition is suboptimal. Does the
> (untested) patch below help things?

I'll give it a try on Monday.

Thanks,

-- Steve