From: chetan loke <loke.chetan@gmail.com>
To: "Keller, Jacob E" <jacob.e.keller@intel.com>
Cc: "e1000-devel@lists.sourceforge.net"
<e1000-devel@lists.sourceforge.net>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"Ronciak, John" <john.ronciak@intel.com>,
"john.stultz@linaro.org" <john.stultz@linaro.org>,
"tglx@linutronix.de" <tglx@linutronix.de>
Subject: Re: [PATCH net V4 2/2] igb: offer a PTP Hardware Clock instead of the timecompare method
Date: Wed, 21 Mar 2012 17:50:34 -0400 [thread overview]
Message-ID: <CAAsGZS6QuMJoXz8mmqZsgfTF2ykRz6KG_nCoPBBkTA4z3idoGA@mail.gmail.com> (raw)
In-Reply-To: <02874ECE860811409154E81DA85FBB580DA6E3@ORSMSX105.amr.corp.intel.com>
On Wed, Mar 21, 2012 at 1:09 PM, Keller, Jacob E
<jacob.e.keller@intel.com> wrote:
>> -----Original Message-----
>> From: Richard Cochran [mailto:richardcochran@gmail.com]
>> Sent: Wednesday, March 21, 2012 10:00 AM
>> To: chetan loke
>> Cc: netdev@vger.kernel.org; e1000-devel@lists.sourceforge.net; Keller, Jacob
>> E; Kirsher, Jeffrey T; Ronciak, John; john.stultz@linaro.org;
>> tglx@linutronix.de
>> Subject: Re: [PATCH net V4 2/2] igb: offer a PTP Hardware Clock instead of the
>> timecompare method
>>
>> Can you please explain how using a seqlock could help here?
>>
>> Thanks,
>> Richard
>
> My understanding of the seqlock, is that it prevents starvation of the hwtstamp calls in the rx and tx routines if/when a user hammers the gettime ioctl due to bad software design where 100+ apps are wanting direct access to the PHC.
>
Richard - Intent is to make the readers(get_time) wait (or return last
read value if the seq_counter tripped because you know that this value
was recent) and let the tx/rx path continue. I haven't looked in more
details but as Jake mentioned you will also need to change the way you
read the values(by not using timecounter_read in get_time).
thanks
Chetan
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next prev parent reply other threads:[~2012-03-21 21:50 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <D3F292ADF945FB49B35E96C94C2061B916484EC4@nsmail.netscout.com>
2012-03-15 17:18 ` [PATCH net V4 2/2] igb: offer a PTP Hardware Clock instead of the timecompare method chetan loke
2012-03-16 6:55 ` Richard Cochran
2012-03-21 15:00 ` chetan loke
2012-03-21 16:08 ` Richard Cochran
2012-03-21 17:02 ` chetan loke
2012-03-22 7:00 ` Richard Cochran
2012-03-21 17:06 ` Keller, Jacob E
2012-03-22 7:09 ` Richard Cochran
2012-03-22 21:59 ` Keller, Jacob E
2012-03-23 6:05 ` Richard Cochran
2012-03-21 17:00 ` Richard Cochran
2012-03-21 17:09 ` Keller, Jacob E
2012-03-21 21:50 ` chetan loke [this message]
2012-03-22 6:41 ` Richard Cochran
2012-03-22 23:13 ` chetan loke
2012-03-23 5:59 ` Richard Cochran
2012-03-23 18:27 ` Keller, Jacob E
2012-03-23 19:39 ` chetan loke
2012-03-24 6:51 ` Richard Cochran
2012-03-26 15:07 ` chetan loke
2012-03-26 15:27 ` Richard Cochran
2012-03-26 17:11 ` chetan loke
2012-03-26 18:56 ` Keller, Jacob E
2012-03-26 19:32 ` chetan loke
2012-03-26 20:46 ` Keller, Jacob E
2012-03-27 18:05 ` Richard Cochran
2012-03-27 18:29 ` Keller, Jacob E
2012-03-27 18:43 ` chetan loke
2012-03-27 18:51 ` chetan loke
2012-03-27 20:58 ` Keller, Jacob E
2012-03-27 21:55 ` chetan loke
2012-03-29 23:08 ` Keller, Jacob E
2012-03-30 15:17 ` chetan loke
2012-03-27 15:33 ` Richard Cochran
2012-03-27 18:39 ` chetan loke
2012-03-26 20:51 ` Keller, Jacob E
2012-03-27 18:33 ` Richard Cochran
2012-01-21 16:03 [PATCH net V4 0/2] igb: ptp hardware clock Richard Cochran
2012-01-21 16:03 ` [PATCH net V4 2/2] igb: offer a PTP Hardware Clock instead of the timecompare method Richard Cochran
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