From: Miroslav Lichvar <mlichvar@redhat.com>
To: intel-wired-lan@osuosl.org
Subject: [Intel-wired-lan] [PATCH] igb: shorten maximum PHC timecounter update interval
Date: Fri, 26 Oct 2018 14:04:16 +0200 [thread overview]
Message-ID: <20181026120416.GB27139@localhost> (raw)
In-Reply-To: <20181012140530.6mjxkb2co3nhl5pf@localhost>
On Fri, Oct 12, 2018 at 07:05:30AM -0700, Richard Cochran wrote:
> On Fri, Oct 12, 2018 at 01:13:39PM +0200, Miroslav Lichvar wrote:
> > Since commit 500462a9d ("timers: Switch to a non-cascading wheel"),
> > scheduling of delayed work seems to be less accurate and a requested
> > delay of 540 seconds may actually be longer than 550 seconds. Shorten
> > the delay to 480 seconds to be sure the timecounter is updated in time.
>
> Good catch. This timer wheel change will affect other, similar
> drivers. Guess I'll go through and adjust their timeouts, too.
I just realized that we need to fit there also any frequency
adjustments of the PHC and system clock. The PHC can be set to run up
to 6% faster and the system clock can be slowed down by up to 10%.
Those 480 seconds in the igb driver is not short enough for that.
Should I fix and resend this patch, or send a new one?
Other drivers may have a similar problem.
--
Miroslav Lichvar
WARNING: multiple messages have this Message-ID (diff)
From: Miroslav Lichvar <mlichvar@redhat.com>
To: Richard Cochran <richardcochran@gmail.com>
Cc: intel-wired-lan@lists.osuosl.org, netdev@vger.kernel.org,
Jacob Keller <jacob.e.keller@intel.com>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH] igb: shorten maximum PHC timecounter update interval
Date: Fri, 26 Oct 2018 14:04:16 +0200 [thread overview]
Message-ID: <20181026120416.GB27139@localhost> (raw)
In-Reply-To: <20181012140530.6mjxkb2co3nhl5pf@localhost>
On Fri, Oct 12, 2018 at 07:05:30AM -0700, Richard Cochran wrote:
> On Fri, Oct 12, 2018 at 01:13:39PM +0200, Miroslav Lichvar wrote:
> > Since commit 500462a9d ("timers: Switch to a non-cascading wheel"),
> > scheduling of delayed work seems to be less accurate and a requested
> > delay of 540 seconds may actually be longer than 550 seconds. Shorten
> > the delay to 480 seconds to be sure the timecounter is updated in time.
>
> Good catch. This timer wheel change will affect other, similar
> drivers. Guess I'll go through and adjust their timeouts, too.
I just realized that we need to fit there also any frequency
adjustments of the PHC and system clock. The PHC can be set to run up
to 6% faster and the system clock can be slowed down by up to 10%.
Those 480 seconds in the igb driver is not short enough for that.
Should I fix and resend this patch, or send a new one?
Other drivers may have a similar problem.
--
Miroslav Lichvar
next prev parent reply other threads:[~2018-10-26 12:04 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-12 11:13 [Intel-wired-lan] [PATCH] igb: shorten maximum PHC timecounter update interval Miroslav Lichvar
2018-10-12 11:13 ` Miroslav Lichvar
2018-10-12 14:05 ` [Intel-wired-lan] " Richard Cochran
2018-10-12 14:05 ` Richard Cochran
2018-10-26 12:04 ` Miroslav Lichvar [this message]
2018-10-26 12:04 ` Miroslav Lichvar
2018-10-26 15:47 ` [Intel-wired-lan] " Keller, Jacob E
2018-10-26 15:47 ` Keller, Jacob E
2018-10-12 14:08 ` [Intel-wired-lan] " Richard Cochran
2018-10-12 14:08 ` Richard Cochran
2018-10-20 1:13 ` [Intel-wired-lan] " Brown, Aaron F
2018-10-20 1:13 ` Brown, Aaron F
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