On Tue, Nov 15, 2016 at 08:24:37PM -0800, Denny Page wrote:
> With the latest drop in the repo, I’m still seeing the wild spikes in the 
> standard deviation with hardware time stamping against the fast responding 
> hardare units. I'm also still seeing a better base deviation using software 
> timestamps against them as well.
> 
> I do see better results with hardware time stamping when doing chrony to 
> chrony, but I believe that this is a result of the general purpose computers 
> being a bit slower to respond than the dedicated hardware units.

Hm, the fix helped with the spikes I was seeking. Did we rule out the
possibility that in your case the spikes are due to the other issue with
out-of-order HW timestamps? Could you try it with this patch to make
sure only measurements with HW timestamps are used?

--- a/ntp_core.c
+++ b/ntp_core.c
@@ -1434,6 +1434,9 @@ receive_packet(NCR_Instance inst, NTP_Local_Address 
*local_addr,
        prevent a synchronisation loop */
     testD = message->stratum <= 1 || REF_GetMode() != REF_ModeNormal ||
             pkt_refid != UTI_IPToRefid(&local_addr->ip_addr);
+
+    if (inst->local_tx.source != NTP_TS_HARDWARE || rx_ts->source != 
NTP_TS_HARDWARE)
+      testB = 0;
   } else {
     offset = delay = dispersion = 0.0;
     sample_time = rx_ts->ts;

-- 
Miroslav Lichvar

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