[ntp:questions] OT: GPS18x LVC failure

Hal Murray hal-usenet at ip-64-139-1-69.sjc.megapath.net
Mon Oct 12 09:18:21 UTC 2009


>Actually those Gb ethernet switches seems to have some really bad and variable
>latencies. My system, before they installed Gb switches, had a consistant
>roundtrip of 140 usec and gave better than 20usec jitter (with 100Mb switches). Since those new switches
>were installed things have gone to hell-- variable roundtrips ( 140usec, 300usec
>and up to 1 sec roundtrip) and much much worse jitter. NOt sure where the problem
>is, but it sure is terrible. 
>Doing a plot of roundtrip vs offset it is definitely one way delay.

Is the problem in the switch or in the host or server?

It's common for high speed network controllers to batch interrupts
by waiting a while before actually generating an interrupt in hopes
that several more packets will arrive or get sent and processed
with only one interrupt.

-- 
These are my opinions, not necessarily my employer's.  I hate spam.




More information about the questions mailing list