From: Dmitry Safonov <dima@arista.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Eric Dumazet <edumazet@google.com>,
Peter Zijlstra <peterz@infradead.org>,
Frederic Weisbecker <frederic@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Dmitry Safonov <0x7f454c46@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
David Miller <davem@davemloft.net>,
Frederic Weisbecker <fweisbec@gmail.com>,
Hannes Frederic Sowa <hannes@stressinduktion.org>,
Ingo Molnar <mingo@kernel.org>,
"Levin, Alexander (Sasha Levin)" <alexander.levin@verizon.com>,
Paolo Abeni <pabeni@redhat.com>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Radu Rendec <rrendec@arista.com>, Rik van Riel <riel@redhat.com>,
Stanislaw Gruszka <sgruszka@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
Wanpeng Li <wanpeng.li@hotmail.com>
Subject: Re: [RFC 1/2] softirq: Defer net rx/tx processing to ksoftirqd context
Date: Thu, 11 Jan 2018 20:46:26 +0000 [thread overview]
Message-ID: <1515703586.3039.30.camel@arista.com> (raw)
In-Reply-To: <CA+55aFxP31rXqGGyh-hvE-wreW0fHgK5JjmvvHEfK6TVrY+qvg@mail.gmail.com>
On Thu, 2018-01-11 at 12:40 -0800, Linus Torvalds wrote:
> On Thu, Jan 11, 2018 at 12:34 PM, Dmitry Safonov <dima@arista.com>
> wrote:
> >
> > I could try to write a PoC for that..
> > What should be the trigger to fall into workqueue?
> > How to tell if there're too many softirqs of the kind?
>
> I suspect it would have to be time-based, probably using the
> scheduler clock.
I thought about this, but I was a bit afraid of how much pricey it
would be recalculate it each clock. Well, might just try to write that
and measure the impact.
> Most softirqs are really really small. So just counting them probably
> isn't all that meaningful, although the count is good as a fallback
> (as shown by the jiffy issues).
>
> The good news is that we only have a fairly small handful of
> softirqs,
> so counting/timing them separately is still mainly a pretty small
> array (which needs to be percpu, of course).
next prev parent reply other threads:[~2018-01-11 20:46 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-09 13:36 [RFC 0/2] Net softirq deferring to ksoftirqd Dmitry Safonov
2018-01-09 13:36 ` [RFC 1/2] softirq: Defer net rx/tx processing to ksoftirqd context Dmitry Safonov
2018-01-09 16:03 ` Frederic Weisbecker
2018-01-10 21:20 ` Dmitry Safonov
2018-01-09 18:02 ` Eric Dumazet
2018-01-10 21:48 ` Dmitry Safonov
2018-01-11 2:13 ` Linus Torvalds
2018-01-11 3:22 ` Frederic Weisbecker
2018-01-11 4:19 ` Linus Torvalds
2018-01-11 4:44 ` Frederic Weisbecker
2018-01-11 14:31 ` Dmitry Safonov
2018-01-11 16:20 ` Eric Dumazet
2018-01-11 16:32 ` Peter Zijlstra
2018-01-11 16:38 ` David Miller
2018-01-11 16:43 ` Peter Zijlstra
2018-01-11 18:48 ` Linus Torvalds
2018-01-11 19:15 ` Eric Dumazet
2018-01-11 19:43 ` Linus Torvalds
2018-01-11 19:48 ` Eric Dumazet
2018-01-11 20:03 ` Linus Torvalds
2018-01-11 20:16 ` Eric Dumazet
2018-01-11 20:22 ` Linus Torvalds
2018-01-11 20:34 ` Dmitry Safonov
2018-01-11 20:37 ` Eric Dumazet
2018-01-11 20:40 ` Linus Torvalds
2018-01-11 20:46 ` Dmitry Safonov [this message]
2018-01-11 20:53 ` Eric Dumazet
2018-01-11 21:13 ` Dmitry Safonov
2018-01-12 5:41 ` Frederic Weisbecker
2018-01-12 5:23 ` Mike Galbraith
2018-01-12 10:13 ` Peter Zijlstra
2018-01-12 17:26 ` Linus Torvalds
2018-01-12 17:44 ` Mike Galbraith
2018-01-12 17:51 ` Linus Torvalds
2018-01-12 18:15 ` Mike Galbraith
2018-01-12 18:44 ` Mike Galbraith
2018-01-17 20:30 ` David Miller
2018-01-17 21:06 ` Linus Torvalds
2018-01-17 21:49 ` David Miller
2018-01-17 21:54 ` Thomas Gleixner
2018-01-17 21:58 ` Linus Torvalds
2018-01-17 22:00 ` Thomas Gleixner
2018-01-17 22:02 ` Eric Dumazet
2018-01-17 22:24 ` David Miller
2018-01-17 22:54 ` Thomas Gleixner
2018-02-06 16:56 ` Sebastian Andrzej Siewior
2018-02-13 16:36 ` Thomas Gleixner
2018-01-17 21:54 ` Linus Torvalds
2018-01-17 21:58 ` Thomas Gleixner
2018-01-12 19:28 ` Thomas Gleixner
2018-01-12 19:53 ` Frederic Weisbecker
2018-01-12 14:58 ` Frederic Weisbecker
2018-01-12 15:15 ` Mike Galbraith
2018-01-12 17:00 ` Frederic Weisbecker
2018-01-12 18:08 ` Mike Galbraith
2018-01-12 17:24 ` Linus Torvalds
2018-01-09 13:36 ` [RFC 2/2] softirq: Introduce mask for __do_softirq() Dmitry Safonov
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