perf: Speedup DecCoin.Sort() when coins is of length 1 (backport #18888…

…) (#18890)

Co-authored-by: Dong Lieu <93205232+DongLieu@users.noreply.github.com>
Co-authored-by: marbar3778 <marbar3778@yahoo.com>

CHANGELOG.md

@@ -46,6 +46,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 ### Improvements
 
+* (types) [#18888](https://github.com/cosmos/cosmos-sdk/pull/18888) Speedup DecCoin.Sort() if len(coins) <= 1
 * (x/gov) [#18707](https://github.com/cosmos/cosmos-sdk/pull/18707) Improve genesis validation. 
 * (server) [#18478](https://github.com/cosmos/cosmos-sdk/pull/18478) Add command flag to disable colored logs.
 

types/dec_coin.go

@@ -611,7 +611,12 @@ func (coins DecCoins) Swap(i, j int) { coins[i], coins[j] = coins[j], coins[i] }
 
 // Sort is a helper function to sort the set of decimal coins in-place.
 func (coins DecCoins) Sort() DecCoins {
-	sort.Sort(coins)
+	// sort.Sort(coins) does a costly runtime copy as part of `runtime.convTSlice`
+	// So we avoid this heap allocation if len(coins) <= 1. In the future, we should hopefully find
+	// a strategy to always avoid this.
+	if len(coins) > 1 {
+		sort.Sort(coins)
+	}
 	return coins
 }