vault backup: 2025-03-25 17:17:22

Concurrent Systems/notes/8 - Enhancing Liveness Properties.md

@@ -103,5 +103,15 @@ We assume a weak timestamp generator, i.e. a function such that, if it returns a
 TS[1..n] : SWMR atomic R/W registers init at 0
 
 need_help(i) :=
-	TS[i]
-```
+	TS[i] <- weak_ts()
+	repeat
+		competing <- {j : TS[j] != 0 and j ∉ suspected_i}
+		⟨t,j⟩ <- min{⟨TS[x],x⟩ | x ∈ competing}
+	until j = i
+
+stop_help(i) :=
+	TS[i] <- 0
+```
+
+##### Theorem:
+the contention manager just seen transforms an obstruction-free implementation into a wait-free enriched implementation.