diff --git a/evm/src/keccak/keccak_stark.rs b/evm/src/keccak/keccak_stark.rs
index de80bf44..53dd66ab 100644
--- a/evm/src/keccak/keccak_stark.rs
+++ b/evm/src/keccak/keccak_stark.rs
@@ -194,7 +194,6 @@ impl<F: RichField + Extendable<D>, const D: usize> KeccakStark<F, D> {
     }
 
     pub fn generate_trace(&self, inputs: Vec<[u64; NUM_INPUTS]>) -> Vec<PolynomialValues<F>> {
-        #[allow(unused_mut)]
         let mut timing = TimingTree::new("generate trace", log::Level::Debug);
 
         // Generate the witness, except for permuted columns in the lookup argument.
diff --git a/evm/src/memory/memory_stark.rs b/evm/src/memory/memory_stark.rs
index bc38e66d..82e10869 100644
--- a/evm/src/memory/memory_stark.rs
+++ b/evm/src/memory/memory_stark.rs
@@ -192,7 +192,6 @@ impl<F: RichField + Extendable<D>, const D: usize> MemoryStark<F, D> {
     }
 
     pub(crate) fn generate_trace(&self, memory_ops: Vec<MemoryOp>) -> Vec<PolynomialValues<F>> {
-        #[allow(unused_mut)]
         let mut timing = TimingTree::new("generate trace", log::Level::Debug);
 
         // Generate most of the trace in row-major form.
diff --git a/plonky2/src/fri/oracle.rs b/plonky2/src/fri/oracle.rs
index c6e3a1ff..312b458b 100644
--- a/plonky2/src/fri/oracle.rs
+++ b/plonky2/src/fri/oracle.rs
@@ -71,7 +71,7 @@ impl<F: RichField + Extendable<D>, C: GenericConfig<D, F = F>, const D: usize>
         rate_bits: usize,
         blinding: bool,
         cap_height: usize,
-        _timing: &mut TimingTree,
+        timing: &mut TimingTree,
         fft_root_table: Option<&FftRootTable<F>>,
     ) -> Self
     where
@@ -79,15 +79,15 @@ impl<F: RichField + Extendable<D>, C: GenericConfig<D, F = F>, const D: usize>
     {
         let degree = polynomials[0].len();
         let lde_values = timed!(
-            _timing,
+            timing,
             "FFT + blinding",
             Self::lde_values(&polynomials, rate_bits, blinding, fft_root_table)
         );
 
-        let mut leaves = timed!(_timing, "transpose LDEs", transpose(&lde_values));
+        let mut leaves = timed!(timing, "transpose LDEs", transpose(&lde_values));
         reverse_index_bits_in_place(&mut leaves);
         let merkle_tree = timed!(
-            _timing,
+            timing,
             "build Merkle tree",
             MerkleTree::new(leaves, cap_height)
         );
diff --git a/plonky2/src/fri/prover.rs b/plonky2/src/fri/prover.rs
index f8467d2b..6136a9a1 100644
--- a/plonky2/src/fri/prover.rs
+++ b/plonky2/src/fri/prover.rs
@@ -23,7 +23,7 @@ pub fn fri_proof<F: RichField + Extendable<D>, C: GenericConfig<D, F = F>, const
     lde_polynomial_values: PolynomialValues<F::Extension>,
     challenger: &mut Challenger<F, C::Hasher>,
     fri_params: &FriParams,
-    _timing: &mut TimingTree,
+    timing: &mut TimingTree,
 ) -> FriProof<F, C::Hasher, D>
 where
     [(); C::Hasher::HASH_SIZE]:,
@@ -33,7 +33,7 @@ where
 
     // Commit phase
     let (trees, final_coeffs) = timed!(
-        _timing,
+        timing,
         "fold codewords in the commitment phase",
         fri_committed_trees::<F, C, D>(
             lde_polynomial_coeffs,
@@ -46,7 +46,7 @@ where
     // PoW phase
     let current_hash = challenger.get_hash();
     let pow_witness = timed!(
-        _timing,
+        timing,
         "find proof-of-work witness",
         fri_proof_of_work::<F, C, D>(current_hash, &fri_params.config)
     );
diff --git a/system_zero/src/system_zero.rs b/system_zero/src/system_zero.rs
index ce44c283..19c2df8c 100644
--- a/system_zero/src/system_zero.rs
+++ b/system_zero/src/system_zero.rs
@@ -69,7 +69,6 @@ impl<F: RichField + Extendable<D>, const D: usize> SystemZero<F, D> {
     }
 
     pub fn generate_trace(&self) -> Vec<PolynomialValues<F>> {
-        #[allow(unused_mut)]
         let mut timing = TimingTree::new("generate trace", log::Level::Debug);
 
         // Generate the witness, except for permuted columns in the lookup argument.