netdev - Re: [net-next 07/12] ixgbe: Enable timesync clock-out feature for PPS support on X540

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20120511054036.GC2170@netboy.at.omicron.at>
Date:	Fri, 11 May 2012 07:40:36 +0200
From:	Richard Cochran <richardcochran@...il.com>
To:	"Keller, Jacob E" <jacob.e.keller@...el.com>
Cc:	"Kirsher, Jeffrey T" <jeffrey.t.kirsher@...el.com>,
	"davem@...emloft.net" <davem@...emloft.net>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
	"gospo@...hat.com" <gospo@...hat.com>,
	"sassmann@...hat.com" <sassmann@...hat.com>
Subject: Re: [net-next 07/12] ixgbe: Enable timesync clock-out feature for
 PPS support on X540

On Thu, May 10, 2012 at 10:08:44PM +0000, Keller, Jacob E wrote:
> 
> Oops stupid mail program sent that on accident. Anyways: I think you might be
> right, Richard. We don't read those timestamp values unless the stat err bit
> for timestamps is set on the descriptor. But I am not sure what happens when the
> tjmestamped packet is dropped off the end of the ring. What would you propose
> here? How can we detect if this timestamp doesn't match the packet? I can look
> into using the extra hardware features for matching timestamps. That might be
> a more useful, in that it would help prevent this case.

[ Talking about the Rx time stamping locking from other patch... ]

The IGB provides some PTP event packet identification fields (seqNum,
etc) just for the purpose of matching time stamps to packets. Some of
the other PHC drivers (ixp4xx, dp83640) have code that does the
matching.

HTH,
Richard


--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html