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From: Jiri Benc <jbenc@redhat.com>
To: Denny Page <dennypage@me.com>
Cc: Miroslav Lichvar <mlichvar@redhat.com>,
	Richard Cochran <richardcochran@gmail.com>,
	netdev@vger.kernel.org, "Keller,
	Jacob E" <jacob.e.keller@intel.com>,
	Willem de Bruijn <willemb@google.com>
Subject: Re: Extending socket timestamping API for NTP
Date: Fri, 24 Mar 2017 10:55:48 +0100	[thread overview]
Message-ID: <20170324105549.34b3e778@griffin> (raw)
In-Reply-To: <6121D504-288F-4C9B-9AB3-D1C8292965D5@me.com>

On Thu, 23 Mar 2017 10:08:00 -0700, Denny Page wrote:
> I am very surprised at this. The application caching approach
> requires the application retrieve the value via a system call. The
> system call overhead is huge in comparison to everything else. More
> importantly, the application cached value may be wrong. If the
> application takes a sample every 5 seconds, there are 5 seconds of
> timestamps that can be wildly wrong.

You can add a netlink event that is sent on speed change. No need for
polling then and the wrong timestamp window will be very tiny. (It
can't be zero, even with per-packet data.)

ethtool needs to be converted to netlink, anyway.

 Jiri

      parent reply	other threads:[~2017-03-24  9:55 UTC|newest]

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-02-07 14:01 Extending socket timestamping API for NTP Miroslav Lichvar
2017-02-07 17:45 ` Keller, Jacob E
2017-02-07 22:32   ` Willem de Bruijn
2017-02-08 14:18     ` Soheil Hassas Yeganeh
2017-02-27 15:23     ` Miroslav Lichvar
2017-02-28  0:01       ` Willem de Bruijn
2017-02-28  8:26         ` Miroslav Lichvar
2017-02-28 21:05           ` Willem de Bruijn
2017-02-08  1:52   ` Denny Page
2017-02-08  5:27     ` Richard Cochran
2017-02-08  5:48       ` Denny Page
2017-02-08 17:27       ` Denny Page
2017-02-07 18:54 ` Soheil Hassas Yeganeh
2017-02-08 10:14   ` Miroslav Lichvar
2017-02-07 20:37 ` sdncurious
2017-02-08 10:26   ` Miroslav Lichvar
2017-02-08 23:27     ` sdncurious
2017-02-08 23:34     ` sdncurious
2017-02-08  1:18 ` Denny Page
     [not found] ` <CAHoNx58u=Fze4e5V2Wb_LiBhka1Mzny3zOVNfvuzjnmQ4wBO=Q@mail.gmail.com>
2017-02-08  3:06   ` Denny Page
2017-02-09  0:45 ` Denny Page
2017-02-09 11:15   ` Miroslav Lichvar
2017-02-09 20:25   ` Denny Page
2017-02-09  8:02 ` Richard Cochran
2017-02-09 11:09   ` Miroslav Lichvar
2017-02-09 19:42     ` sdncurious
2017-02-09 20:37       ` Denny Page
2017-02-10  0:33       ` Denny Page
2017-02-10 18:55         ` Denny Page
2017-03-23 16:21     ` Miroslav Lichvar
2017-03-23 18:54       ` Denny Page
2017-03-23 19:07       ` Richard Cochran
2017-03-24  7:25         ` Miroslav Lichvar
     [not found]       ` <6121D504-288F-4C9B-9AB3-D1C8292965D5@me.com>
2017-03-24  9:45         ` Miroslav Lichvar
2017-03-24 17:17           ` Denny Page
2017-03-24 18:52             ` Keller, Jacob E
2017-03-27 10:13             ` Miroslav Lichvar
2017-03-27 14:29               ` Richard Cochran
2017-03-27 16:25                 ` Denny Page
2017-03-27 18:28                   ` Richard Cochran
2017-03-27 19:18                     ` Denny Page
2017-03-27 20:58                       ` Richard Cochran
2017-03-27 21:20                         ` Denny Page
2017-03-27 19:21                     ` Denny Page
2017-03-27 19:21                     ` Denny Page
     [not found]                     ` <5FD283AB-39DE-4A9D-902A-BA5F0F0B62A3@me.com>
2017-03-27 21:00                       ` Richard Cochran
2017-03-24  9:55         ` Jiri Benc [this message]

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