tor 2026-02-12 klockan 17:34 +0100 skrev Bertho Stultiens: > On 2/12/26 5:08 PM, Peter Wallace wrote: > > > Is there anybody who has a LinuxCNC instance that runs for more than > > > (multiples of) about 49 days at a time (that is for a 1kHz servo-thread)? > > > There is a race condition when a 32-bit heartbeat counter wraps. It > > > can only be hit every ~49 days within a time window of one servo- > > > thread period (usually 1ms). So, the chance of hitting the race is > > > very remote and can only be hit if you are actively tracking the > > > heartbeat variable, which usually nobody does. > > > So, does it need to be taken care of or should it be considered academic? > > I have run hardware tests for up to 3 months or so. > > That is nice! > > > > What would the wrap of the heratbeat counter do? > > It could cause the difference calculation of two temporally separated > values of the heartbeat counter to result in the wrong result (a > negative difference instead of a positive one). If done right result should always be positive if it is an increasing provided counter is checked more often than ~24½ days.
Calculations are probably best tested write a small "hello world" type program there a few calculations around the wrap point is calculated. Nicklas Karlsson _______________________________________________ Emc-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
