[LinuxPPS] LinuxPPS comparable to FreeBSD here

[Remco dB]

Dear all, 

For some time now I run my LinuxPPS (thermostatised!) system with kernel 
2.6.34, CONFIG_NO_HZ and CONFIG_HZ=1000 set and no hardpps.

Compared to my (also thermostatised) FreeBSD system (with hardpps) LinuxPPS 
performs almost equally. 

See http remco.org/ntp

What I see it that the jitter (or 'rrdtool average') of LinuxPPS is less than 
my FreeBSD jitter (i.e. freebsd and helium).

Both freebsd and helium are within the +/- 2 us range, roughly.

ntp2.remco.org runs also 2.6.34, CONFIG_NO_HZ, CONFIG_HZ=1000 and no hardpps
on a (remote) system, using an old 450 MHz machine with a PIT timer. The 
system is not thermostatised and shows some temperature dependencies, but the 
jitter far less than my other systems. Interesting . . . 
Perhaps, when thermostatised it would produce a 'flat liner' ? 

So I wonder, would adding hardpps _improve_ the LinuxPPS performance, 
considering 'general hardware boundary conditions'?

Currently I can't find out ;-( 

Maybe Alexander is willing to publish a cookbook recipe to apply his kcbind 
patches, modified timepps.h etc etc so that the whole arrangement will compile 
for somebody who is more into hardware? ;-)

Remco