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From: Clark Williams <clrkwllms@kernel.org>
To: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Huacai Chen <chenhuacai@kernel.org>,
	Huacai Chen <chenhuacai@loongson.cn>,
	Xuerui Wang <kernel@xen0n.name>,
	loongarch@lists.linux.dev, Steven Rostedt <rostedt@goodmis.org>,
	linux-rt-devel@lists.linux.dev, Guo Ren <guoren@kernel.org>,
	Jiaxun Yang <jiaxun.yang@flygoat.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/3] LoongArch: Allow to enable PREEMPT_RT
Date: Thu, 14 Nov 2024 08:43:21 -0600	[thread overview]
Message-ID: <ZzYMie7ktV8ByaQF@demetrius> (raw)
In-Reply-To: <20241114132956.wafcHvaB@linutronix.de>

On Thu, Nov 14, 2024 at 02:29:56PM +0100, Sebastian Andrzej Siewior wrote:
> 
> Ach okay. So the pure read on the slow bus causes a delay because the
> CPU is stalled. That is not limited to chrony but should also have an
> affect if the user uses hwclock to read/ write the time.
> 
> Sebastian
> 

We see similar problems with chronyd accessing the RTC on aarch64
systems that use UEFI. Accessing anything via the EFI Runtime is very
slow. Probably going to turn off 'rtcsync' in chronyd when running
low-latency workloads. 

Clark

-- 
The United States Coast Guard
Ruining Natural Selection since 1790

  reply	other threads:[~2024-11-14 14:43 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-11-08  9:15 [PATCH 0/3] LoongArch: Add PREEMPT_RT support Huacai Chen
2024-11-08  9:15 ` [PATCH 1/3] LoongArch: Reduce min_delta for the arch clockevent device Huacai Chen
2024-11-14 10:21   ` Sebastian Andrzej Siewior
2024-11-14 11:46     ` Huacai Chen
2024-11-14 13:27       ` Sebastian Andrzej Siewior
2024-11-15  6:44         ` Huacai Chen
2024-11-08  9:15 ` [PATCH 2/3] LoongArch: Select HAVE_POSIX_CPU_TIMERS_TASK_WORK Huacai Chen
2024-11-08  9:15 ` [PATCH 3/3] LoongArch: Allow to enable PREEMPT_RT Huacai Chen
2024-11-08 15:05   ` Steven Rostedt
2024-11-14 10:31   ` Sebastian Andrzej Siewior
2024-11-14 11:07     ` Huacai Chen
2024-11-14 11:14       ` Sebastian Andrzej Siewior
2024-11-14 11:19         ` Huacai Chen
2024-11-14 11:30           ` Sebastian Andrzej Siewior
2024-11-14 11:36             ` Huacai Chen
2024-11-14 13:29               ` Sebastian Andrzej Siewior
2024-11-14 14:43                 ` Clark Williams [this message]
2024-11-18  7:36                   ` Sebastian Andrzej Siewior
     [not found]                     ` <CAPAFJkp_MQ8rNsTTY3xfYMhdtiWQunN65Yfft1SqZLptG2J5cw@mail.gmail.com>
2024-11-20  7:36                       ` Sebastian Andrzej Siewior

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