[Xorp-hackers] Question of FEA strace

[Ben Greear]

Bruce M Simpson wrote:

> [This means it's going to be subject to general relativity, although 
> that is *currently* not a XORP design issue until we start installing 
> XORP on communications satellites, hopefully well within the next 5 years.]

You'll have way more drift based on heat of the chip than relativity I think :)

> Windows uses GetSystemTimeAsFileTime(), as this is the path of least 
> resistance. The "right thing" to do there is probably to use 
> GetTickCount64(), however this is Vista only -- it's entirely possible, 
> though unlikely, that a XORP process timer could be scheduled 50 days in 
> advance, or that the delta could span 50 days.

Window's file-timer only updates every 10ms or so.  This is probably
fine for Xorp, but it plays merry hell if you want to do fine-grain
timer things...

I have code that uses the windows cycle timer and periodically re-correlates
this with the file-time (which may be updated with ntp or equiv).  If
you ever need better than 10ms resolution, let me know and I'll
send you my hackings.  My code seems to work on Windows 2000 and XP, haven't
tried it on Vista.

Thanks,
Ben

-- 
Ben Greear <greearb at candelatech.com>
Candela Technologies Inc  http://www.candelatech.com