On 02/24/2016 06:23 PM, Keller, Jacob E wrote: >> -----Original Message----- >> Finally a collegue used the patch below and the problem vanished(above >> test code did run a long time), >> however it is unclear if the timestamps produced are still 'correct' and >> useful for ptp. >> The fix still looks surprising.. >> >> kind regards >> Frank >> > This is the work-around I was talking about below. I am surprised it is not > in the 4.4 kernel? > > This is a known hardware errata on some of the parts (I am not sure which > ones) and it should have had the workaround pushed upstream. I am guessing > your collegue got this from the out-of-tree driver on SourceForge
Hi, no, we looked at the 4.4 Code and backported it to 3.19, but our testcase still showed the problem. Thought "this workaround cannot work if..." and created the patch below ourselfes. Need to check sourceforge.. We were surprised that it helped, basically we did not understand what kind of hardware bug might cause more than one overflow in such a small amount of time. It is not clear to me if the "time" produced by the intel chips using our patch is "valid" at all, or if it would be better just to remove the PTP clock from the affected Intel drivers completely. Backgrund: What I see in the setup currently are spikes in the PTP time distributed by linuxptp. We investigated the components and found a problem in the intel driver and a testcase to reproduce it, developed a patch for the testcase, but the spikes are still there... (We have a beagleboard in the system too and suspect problems which might be related to parallel NFS traffic , but found no simple testcase for this.) What our testcase confirms is that the results from clock_gettime() jumped wildly around before our patch and did not do this after applying the patch. A constant counter or somethings with a jitter having an amplitude below 1s would pass our testcase too... Any opinion very much appreciated. kind regards Frank ------------------------------------------------------------------------------ Site24x7 APM Insight: Get Deep Visibility into Application Performance APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month Monitor end-to-end web transactions and take corrective actions now Troubleshoot faster and improve end-user experience. Signup Now! http://pubads.g.doubleclick.net/gampad/clk?id=272487151&iu=/4140 _______________________________________________ Linuxptp-users mailing list Linuxptp-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linuxptp-users
