From: Andrea Righi <andrea.righi@canonical.com>
To: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Uladzislau Rezki <urezki@gmail.com>,
Joel Fernandes <joel@joelfernandes.org>,
Joel Fernandes <joelaf@google.com>,
rcu@vger.kernel.org,
"Cc: Frederic Weisbecker" <fweisbec@gmail.com>
Subject: Re: Observation on NOHZ_FULL
Date: Thu, 15 Feb 2024 08:51:54 +0100 [thread overview]
Message-ID: <Zc3CmvuD79umJXQv@gpd> (raw)
In-Reply-To: <92cba6df-01de-4daa-a0cb-5fa92c7374dd@paulmck-laptop>
On Tue, Feb 06, 2024 at 10:44:33AM -0800, Paul E. McKenney wrote:
...
> >
> > - with lazy RCU enabled hrtimer_interrupt() takes like 2x more to
> > return, respect to the other cases (is this expected?)
>
> This last is surprising at first glance, but I could be missing
> something. Joel, Uladzislau, thoughts?
On this specific point, I repeated the tests with the latest 6.8
kernel and now I don't notice this difference anymore.
hrtimer_interrupt() time is always in the range [4K, 16K) ns, both with
lazy RCU off and lazy RCU on.
I don't really know why I was getting different results, probably some
noise triggered by something running in user-space...?
In any case I will update my old post with these new results and I
wouldn't consider this an issue for now.
Thanks,
-Andrea
next prev parent reply other threads:[~2024-02-15 7:51 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-29 17:47 Observation on NOHZ_FULL Joel Fernandes
2024-01-29 20:41 ` Paul E. McKenney
2024-01-29 22:16 ` Joel Fernandes
2024-01-30 6:58 ` Andrea Righi
2024-01-30 10:17 ` Paul E. McKenney
2024-01-30 11:06 ` Uladzislau Rezki
2024-01-30 11:27 ` Andrea Righi
2024-01-30 11:41 ` Uladzislau Rezki
2024-01-30 13:39 ` Paul E. McKenney
2024-02-06 17:51 ` Andrea Righi
2024-02-06 18:44 ` Paul E. McKenney
2024-02-07 13:04 ` Uladzislau Rezki
2024-02-07 15:12 ` Andrea Righi
2024-02-07 15:49 ` Joel Fernandes
2024-02-15 7:51 ` Andrea Righi [this message]
2024-02-15 13:15 ` Uladzislau Rezki
2024-02-15 14:02 ` Joel Fernandes
2024-02-07 15:48 ` Joel Fernandes
2024-02-07 16:31 ` Andrea Righi
2024-02-07 16:52 ` Joel Fernandes
2024-02-07 17:05 ` Andrea Righi
2024-02-08 5:54 ` Joel Fernandes
2024-02-08 6:55 ` Andrea Righi
2024-02-08 12:53 ` Uladzislau Rezki
2024-02-08 14:51 ` Uladzislau Rezki
2024-02-12 0:22 ` Joel Fernandes
2024-02-12 9:05 ` Uladzislau Rezki
2024-02-12 9:44 ` Uladzislau Rezki
2024-01-29 20:48 ` Uladzislau Rezki
2024-01-29 22:20 ` Joel Fernandes
2024-01-29 22:43 ` Frederic Weisbecker
2024-01-29 22:53 ` Joel Fernandes
2024-01-29 23:11 ` Frederic Weisbecker
2024-01-29 23:36 ` Joel Fernandes
2024-01-30 0:40 ` Paul E. McKenney
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