From: Sebastian Siewior <bigeasy@linutronix.de>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>,
RT-users <linux-rt-users@vger.kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Steven Rostedt <rostedt@goodmis.org>,
Julia Cartwright <julia@ni.com>, Wargreen <wargreen@lebib.org>
Subject: Re: [patch RT 0/4] rwsem/rt: Lift the single reader restriction
Date: Tue, 4 Apr 2017 16:01:02 +0200 [thread overview]
Message-ID: <20170404140102.t3u3hki6y2gtltzm@linutronix.de> (raw)
In-Reply-To: <20170401105058.958246042@linutronix.de>
On 2017-04-01 12:50:58 [+0200], Thomas Gleixner wrote:
> R/W semaphores in RT do not allow multiple readers because a writer
> blocking on the sempahore would have deal with all the readers in terms of
> priority or budget inheritance. While multi reader priority boosting would
> be possible (it has been attempted before), multi reader budget inheritance
> is impossible.
…
> It cures the Radeon mess, lowers the contention on mmap_sem for certain
> workloads and did not have any negative impact in our initial testing on RT
> behaviour.
>
> I think it's worth to expose it to a wider audience of users for testing,
> so we can figure out it whether there are dragons lurking.
series applied.
> Thanks,
>
> tglx
Sebastian
prev parent reply other threads:[~2017-04-04 14:01 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-01 10:50 [patch RT 0/4] rwsem/rt: Lift the single reader restriction Thomas Gleixner
2017-04-01 10:50 ` [patch RT 1/4] rtmutex: Make lock_killable work Thomas Gleixner
2017-04-03 15:21 ` Steven Rostedt
2017-04-04 7:13 ` Peter Zijlstra
2017-04-04 13:20 ` Steven Rostedt
2017-04-01 10:51 ` [patch RT 2/4] rtmutex: Provide rt_mutex_lock_state() Thomas Gleixner
2017-04-01 10:51 ` [patch RT 3/4] rtmutex: Provide locked slowpath Thomas Gleixner
2017-04-01 10:51 ` [patch RT 4/4] rwsem/rt: Lift single reader restriction Thomas Gleixner
2017-04-04 14:01 ` Sebastian Siewior [this message]
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