RE: [PATCH net V4 2/2] igb: offer a PTP Hardware Clock instead of the timecompare method

-----Original Message-----
From: Richard Cochran [mailto:richardcochran@gmail.com]
Sent: Friday, March 23, 2012 11:52 PM
To: chetan loke
Cc: Keller, Jacob E; netdev@vger.kernel.org; e1000-
devel@lists.sourceforge.net; 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

quoted

How about rate limiting at the PHC class driver level? And then it
will work across the board for all the adapters at the device level.

No, don't go there. Enough bikeshedding already. If you have a serious
performance issue, please post a test case, and we will look for a solution.

This is about a case where the user does something stupid. (runs the ioctls too
fast). It appears that your answer is something like "The user did something
stupid, we shouldn't care". My answer is, "we should do what we can to prevent
this." I don't think modifying the ptp framework is necessary or even a good
idea. (Because it is a particular issue with intel parts design, not with general
PTP design.) I do think if possible we should modify igb/ixgbe patches properly
to prevent the breaking. I am currently working on a test case where the user
*does* hammer the ioctls and seeing whether that actually crashes the driver.

Thanks,
Richard