From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: alison@peloton-tech.com, LKML <linux-kernel@vger.kernel.org>,
linux-rt-users <linux-rt-users@vger.kernel.org>,
netdev <netdev@vger.kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>,
Clark Williams <williams@redhat.com>,
Eric Dumazet <eric.dumazet@gmail.com>,
David Miller <davem@davemloft.net>
Subject: Re: [PATCH][RT] netpoll: Always take poll_lock when doing polling
Date: Fri, 10 Jun 2016 18:20:22 +0200 [thread overview]
Message-ID: <8582eb37-3b5b-ee7e-3a67-8f4609b0ac3f@linutronix.de> (raw)
In-Reply-To: <20160610121118.03f281e8@gandalf.local.home>
On 06/10/2016 06:11 PM, Steven Rostedt wrote:
>> It is true that in RT we don't have such a limit like in !RT. You would
>> need to use __raise_softirq_irqoff_ksoft() instead the normal or +
>> wakeup() since you may have timers pending and those need to go to the
>> "other" ksoftirqd.
>> But then I don't see much change. ksoftirqd runs now at SCHED_OTHER so
>> it will end up on the CPU right away unless there other tasks that need
>> the CPU. So the scheduler will balance it the same way. The only change
>> will be that softirqs which are processed in context of any application
>> for more than two jiffies will be moved to ksoftirqd. This could be a
>> win.
>
> We actually triggered a starvation due to this. I was just seeing if
> Alison hit the same issue we did in our tests.
Okay. Didn't get this information from him. But this is only because
the softirqs not running in ksoftirqd, right?
> -- Steve
>
Sebastian
next prev parent reply other threads:[~2016-06-10 16:20 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-26 23:56 [PATCH][RT] netpoll: Always take poll_lock when doing polling Steven Rostedt
2016-06-02 16:12 ` Sebastian Andrzej Siewior
2016-06-04 11:11 ` Steven Rostedt
2016-06-05 15:16 ` Alison Chaiken
2016-06-06 12:03 ` Clark Williams
2016-06-06 23:25 ` Alison Chaiken
2016-06-07 9:46 ` Sebastian Andrzej Siewior
2016-06-08 0:19 ` Alison Chaiken
2016-06-09 12:37 ` Sebastian Andrzej Siewior
2016-09-03 23:40 ` Alison Chaiken
2016-06-10 15:57 ` Sebastian Andrzej Siewior
2016-06-10 16:11 ` Steven Rostedt
2016-06-10 16:20 ` Sebastian Andrzej Siewior [this message]
2016-06-10 16:45 ` Steven Rostedt
2016-06-10 15:30 ` Sebastian Andrzej Siewior
2016-06-10 16:28 ` Eric Dumazet
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