> -----Original Message----- > From: Keller, Jacob E [mailto:[email protected]] > Sent: Thursday, April 27, 2017 3:58 PM > To: Richard Cochran <[email protected]>; David Mirabito > <[email protected]> > Cc: [email protected] > Subject: Re: [Linuxptp-devel] Workaround for 'timed out while polling for tx > timestamp' on IGB > > > -----Original Message----- > > From: Richard Cochran [mailto:[email protected]] > > Sent: Thursday, April 27, 2017 11:25 AM > > To: David Mirabito <[email protected]> > > Cc: [email protected] > > Subject: Re: [Linuxptp-devel] Workaround for 'timed out while polling for tx > > timestamp' on IGB > > > > On Thu, Apr 27, 2017 at 03:41:03PM +1000, David Mirabito wrote: > > > * "Fixing" (if this is indeed a bug) was reasonably straight forward - > > > more > > > or less reordering steps 4,5,6 so that we wake the app only *after* we've > > > unlocked the bit. > > > > If your analysis was correct, then yes, indeed this is a driver bug. > > Please submit a patch on netdev. > > > > Can I clarify here, David, you're suggesting that you instead clear the > bitlock > earlier before you call the timestamp function? I think that's probably a good > thing and minimizing the time that we hold a lock is good. I suspect that > most of > the Intel drivers are at fault here and can make some patches for them. Or you > can if you wish. > > There *is* a fundamental limit that the hardware assumes that only one > transmit > timestamp request at a time, so we can't actually do any better. But we can > unlock as soon as we read the timestamp registers, which should help this > race. > > Thanks, > Jake
I sent a patch to Intel Wired LAN, and I Cc'd both of you on it. Feel free to comment. I fixed up e1000e, igb, ixgbe, and i40e. Please comment indicating if you think this fix is correct. I believe it is correct from your original comment. One change we could make as well, is to increment the timestamp dropped counter for Tx whenever we get a request that we can't fulfill, but I didn't change that in my current patch. Thanks, Jake ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Linuxptp-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/linuxptp-devel
