Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:2 as permitted sender) client-ip=2620:137:e000::3:2;
Date:   Sat, 2 Dec 2023 18:45:07 -0500
From:   Steven Rostedt <rostedt@goodmis.org>
To:     "Paul E. McKenney" <paulmck@kernel.org>
Cc:     LKML <linux-kernel@vger.kernel.org>, rcu@vger.kernel.org,
        Frederic Weisbecker <fweisbec@gmail.com>,
        Joel Fernandes <joel@joelfernandes.org>,
        Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Subject: Re: [RCU] rcu_tasks_trace_qs(): trc_reader_special.b.need_qs value
 incorrect likely()?
Message-ID: <20231202184507.26178c17@rorschach.local.home>
In-Reply-To: <b0772bf3-5b47-4aea-b964-17a2bebc6313@paulmck-laptop>
References: <20231201154932.468d088b@gandalf.local.home>
        <b0772bf3-5b47-4aea-b964-17a2bebc6313@paulmck-laptop>
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Precedence: bulk

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