On Sat, Feb 21, 2015 at 05:51:16PM -0800, Gary E. Miller wrote: > I guess I got lucky and software timestamping is working for me on > an Intel 80003ES2LAN. It uses the e1000e driver, marked as hardware > supported, but does not have hardware support.
Right, the e1000e driver supports a whole family of cards, only some of which have hardware time stamping. > I'm getting 5 uSec jitter between one hardware timing host and one software > time host. Sounds about right, actually pretty good. Adding a CPU and/or network load should make it worse. > Sadly it would not work on a WiFi port, even though 'ethtool -T' shows > the port supports software timestamping. Is there a better way to tell > what it supported? Unfortunately not. Things are getting better as time goes on. Regarding wifi, does it say "software-transmit" as well as "software-receive", or software-receive only? PTP doesn't work well anyhow over wifi because of the unpredicable transmission scheme. The newer wireless protocol actually includes a ptp-like synchronization scheme, but I am not aware of any hardware or software implementations. > I am using kernel 3.19.0. Good. > The supported NICs are a bit pricey, $40 and up, when a nice GigE > card can be $15. I ordered two so I can test a three way hardware > setup. The trend is to include PTP support in newer designs. I guess that it will eventually become a standard feature in most MACs. Cheers, Richard ------------------------------------------------------------------------------ Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server from Actuate! Instantly Supercharge Your Business Reports and Dashboards with Interactivity, Sharing, Native Excel Exports, App Integration & more Get technology previously reserved for billion-dollar corporations, FREE http://pubads.g.doubleclick.net/gampad/clk?id=190641631&iu=/4140/ostg.clktrk _______________________________________________ Linuxptp-devel mailing list Linuxptp-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linuxptp-devel
