pub const DEADLINE_CHECK_INTERVAL: u64 = 64;Expand description
How many Budget::safepoint calls pass between checks of the wall clock
when a deadline is set.
Instant::now() reads a monotonic clock, which on most platforms is a
system call or vDSO trap — several orders of magnitude slower than
decrementing an integer. Checking it at every safepoint would tax
fuel-heavy loops for a bound that fuel usually enforces anyway. Every
DEADLINE_CHECK_INTERVALth call keeps the wasted overrun bounded to a
small, fixed number of safepoints without paying the clock’s cost on every
one. When no fuel limit is set, nothing else bounds the run, so the clock
is consulted on every call regardless of this constant.