Let's consider a simple scenario:
Router R1 in AS100, which has direct connections to routers R2 (AS200), R3 (AS300), R4 (AS400), R5 (AS500). Regular eBGP neighborships are formed over these links. Let's assume they are operational for a while to avoid discussing things like MRAI, update-delay etc.
At some point in time, R1 receives prefix p from its neighbors and all incoming updates are 300 msec apart.
How many times will R1 run its best path algorithm? Is there any mechanism that throttles best path algorithm, as it is in link-state protocols?
After some additional research I tend to think that BGP best path algorithm run is not throttled.
I checked outputs on a BGP router carrying full Internet table with 2 Tier-1 upstreams - BGP table version increments by ~1000 per minute. This means that in a minute, there were around 1000 changes in the table (~ 1000 prefixes has new best path). Since best path runs on a per-prefix basis, I cannot imagine to have it throttled.