Comments and fixes

plutus-benchmark/plutus-benchmark.cabal

@@ -300,6 +300,7 @@ benchmark validation-full
     , base                     >=4.9     && <5
     , bytestring
     , criterion                >=1.5.9.0
+    , deepseq
     , directory
     , filepath
     , flat                     ^>=0.6

plutus-benchmark/validation/bench/BenchFull.hs

@@ -7,6 +7,7 @@ import PlutusLedgerApi.V1
 import UntypedPlutusCore qualified as UPLC
 
 import Common
+import Control.DeepSeq (force)
 import Control.Exception
 import Criterion
 import Data.ByteString as BS

plutus-core/plutus-core/src/PlutusCore/Evaluation/Machine/MachineParameters/Default.hs

@@ -69,7 +69,7 @@ mkMachineParametersFor semVars newCMP = do
         -- See Note [Inlining meanings of builtins].
         (,) semVar . inline mkMachineParameters semVar <$>
             applyCostModelParams (toCekCostModel semVar) newCMP
-    -- Force all thunks to pay the costs of creating machine parameters upfront. Doing it here saves
+    -- Force all thunks to pay the cost of creating machine parameters upfront. Doing it here saves
     -- us from doing that in every single benchmark runner.
     pure $! force res
 -- Not marking this function with @INLINE@, since at this point everything we wanted to be inlined

plutus-ledger-api/src/PlutusLedgerApi/Common/Eval.hs

@@ -127,6 +127,15 @@ cache using a semantics variant as a key. We compute the semantics variant from
 version using the stored function. Note that the semantics variant depends on the language version
 too, but the latter is known statically (because each language version has its own evaluation
 context), hence there's no reason to require it to be provided at runtime.
+
+The reason why we associate a 'DefaultMachineParameters' with a semantics variant rather than a
+protocol version are
+
+1. generally there are far more protocol versions than semantics variants supported by a specific
+   language version, so we save on pointless duplication of bundles of machine parameters
+2. builtins don't know anything about protocol versions, only semantics variants. It is therefore
+   more semantically precise to associate bundles of machine parameters with semantics variants than
+   with protocol versions
 -}
 data EvaluationContext = EvaluationContext
     { _evalCtxLedgerLang    :: PlutusLedgerLanguage