Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Tue, 2 Oct 2018 08:31:59 +0200
From:   Daniel Wagner <wagi@monom.org>
To:     Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc:     linux-kernel@vger.kernel.org,
        Daniel Wagner <daniel.wagner@siemens.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Will Deacon <will.deacon@arm.com>, x86@kernel.org,
        Linus Torvalds <torvalds@linux-foundation.org>,
        "H. Peter Anvin" <hpa@zytor.com>,
        Boqun Feng <boqun.feng@gmail.com>,
        "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Subject: Re: [Problem] Cache line starvation
Message-ID: <20181002063159.r4hxljpzyxpsdg5s@helium.monom.org>
References: <20180921120226.6xjgr4oiho22ex75@linutronix.de>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20180921120226.6xjgr4oiho22ex75@linutronix.de>
User-Agent: NeoMutt/20180716
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Fri, Sep 21, 2018 at 02:02:26PM +0200, Sebastian Andrzej Siewior wrote:
> This matches Daniel Wagner's observations which he described in [0] on
> v4.4-RT.

Peter Z recommended to drop to ticket spinlocks instead trying to port
back all the qspinlock changes to v4.4-rt.

With ticket spinlocks, 'stress-ng --ptrace 4' run for 50 hours without
a problem (before it was seconds) and my normal workload for -rt testing
for 60 hours without a problem (before it broke within 24h).

The cyclictest max values went slightly down from 32us to 30us but
that might just be coincidence.

Thanks,
Daniel