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From: Miroslav Lichvar <mlichvar@redhat.com>
To: Jason Gunthorpe <jgg@ziepe.ca>
Cc: linux-kernel@vger.kernel.org,
	Thomas Gleixner <tglx@linutronix.de>,
	John Stultz <john.stultz@linaro.org>,
	Prarit Bhargava <prarit@redhat.com>
Subject: Re: [PATCH] rtc: adapt allowed RTC update error
Date: Tue, 1 Dec 2020 18:14:20 +0100	[thread overview]
Message-ID: <20201201171420.GN1900232@localhost> (raw)
In-Reply-To: <20201201161224.GF5487@ziepe.ca>

On Tue, Dec 01, 2020 at 12:12:24PM -0400, Jason Gunthorpe wrote:
> On Tue, Dec 01, 2020 at 03:38:35PM +0100, Miroslav Lichvar wrote:
> > +	unsigned long time_set_nsec_fuzz;
> > +	static unsigned int attempt;
> 
> Adding a static value instide a static inline should not be done

Well, grepping through the other header files in include/linux, this
would not be the first case.

> I'm not sure using a static like this is the best idea anyhow, if you
> want something like this it should be per-rtc, not global

If there are multiple RTCs, are they all updated in this 11-minute
sync?

> Did you look at why time has become so in-accurate in your system? 5
> jiffies is usually a pretty long time?

I found no good explanation. It seems to depend on what system is
doing, if it's idle, etc. I suspect it's a property of the workqueues
that they cannot generally guarantee the jobs to run exactly on time.
I tried switching to the non-power-efficient and high priority
workqueues and it didn't seem to make a big difference.

-- 
Miroslav Lichvar


  reply	other threads:[~2020-12-01 17:15 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-01 14:38 [PATCH] rtc: adapt allowed RTC update error Miroslav Lichvar
2020-12-01 16:12 ` Jason Gunthorpe
2020-12-01 17:14   ` Miroslav Lichvar [this message]
2020-12-01 17:35     ` Jason Gunthorpe
2020-12-02 10:01       ` [PATCHv2] " Miroslav Lichvar
2020-12-02 13:44       ` [PATCH] " Thomas Gleixner
2020-12-02 15:07         ` Miroslav Lichvar
2020-12-02 15:36           ` Miroslav Lichvar
2020-12-02 18:36             ` Thomas Gleixner
2020-12-02 16:27         ` Jason Gunthorpe
2020-12-02 19:21           ` Thomas Gleixner
2020-12-02 20:54             ` Jason Gunthorpe
2020-12-02 22:08               ` Thomas Gleixner
2020-12-02 23:03                 ` Jason Gunthorpe
2020-12-03  1:14                 ` Thomas Gleixner
2020-12-03  2:04                   ` Jason Gunthorpe
2020-12-03  2:10                   ` Alexandre Belloni
2020-12-03 15:39                     ` Thomas Gleixner
2020-12-03 16:16                       ` Jason Gunthorpe
2020-12-03 21:05                         ` Thomas Gleixner
2020-12-03 21:31                           ` Thomas Gleixner
2020-12-03 22:36                             ` Jason Gunthorpe
2020-12-04 13:02                               ` Thomas Gleixner
2020-12-04 14:08                                 ` Jason Gunthorpe
2020-12-04 14:37                                   ` Alexandre Belloni
2020-12-04 14:46                                     ` Jason Gunthorpe
2020-12-04 15:08                                       ` Alexandre Belloni
2020-12-04 15:57                                         ` Jason Gunthorpe
2020-12-04 16:35                                           ` Alexandre Belloni
2020-12-03 22:00                           ` Alexandre Belloni
2020-12-04  9:34                             ` Thomas Gleixner
2020-12-04  9:51                               ` Alexandre Belloni
2020-12-04 10:44                                 ` Thomas Gleixner
2020-12-03 17:29                       ` Alexandre Belloni
2020-12-03 19:52                         ` Thomas Gleixner
2020-12-03 15:52                     ` Jason Gunthorpe
2020-12-03 16:07                       ` Alexandre Belloni
2020-12-03 20:10                         ` Jason Gunthorpe

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