bench: use seeded RNG for glass_pumpkin prime generation benchmarks

Use glass_pumpkin's from_rng() API with a seeded ChaCha8Rng instead of
new() which uses OsRng internally, making these benchmarks deterministic.
num-primes doesn't expose an RNG parameter so it remains non-deterministic.

Author: sylvestre

Cargo.lock

@@ -14,6 +14,8 @@ num-bigint = { version = "0.4", features = ["rand"] }
 num-prime = { path = "..", features = ["big-int"] }
 criterion = { version = "4.3.0", package = "codspeed-criterion-compat" }
 rand = "0.8"
+rand_chacha = "0.10"
+rand_core = "0.10"
 num-primes = { version = "0.3.0", optional = true }
 primal-check = "0.3.1"
 is_prime = "2.0.7"
@@ -24,5 +26,3 @@ number-theory = "0.0.6"
 
 [features]
 default = ["num-primes"]
-
-

bench/Cargo.toml

@@ -10,6 +10,8 @@ use num_prime::{nt_funcs, RandPrime};
 use num_primes::{Generator, Verification};
 use rand::rngs::StdRng;
 use rand::SeedableRng;
+use rand_chacha::ChaCha8Rng;
+use rand_core::SeedableRng as SeedableRng2;
 
 #[cfg(target_arch = "x86_64")]
 use number_theory::NumberTheory;
@@ -221,8 +223,12 @@ pub fn bench_prime_gen(c: &mut Criterion) {
     group.bench_function("num-prime (this crate)", |b| {
         b.iter(|| -> num_bigint::BigUint { rng.gen_prime(256, None) })
     });
+    // Note: num-primes uses thread_rng() internally, so this benchmark is not deterministic
     group.bench_function("num-primes", |b| b.iter(|| Generator::new_prime(256)));
-    group.bench_function("glass_pumpkin", |b| b.iter(|| gprime::new(256)));
+    let mut rng_gp = ChaCha8Rng::seed_from_u64(257);
+    group.bench_function("glass_pumpkin", |b| {
+        b.iter(|| gprime::from_rng(256, &mut rng_gp))
+    });
     group.finish();
 
     let mut group = c.benchmark_group("safe prime generation (256 bits)");
@@ -232,8 +238,12 @@ pub fn bench_prime_gen(c: &mut Criterion) {
     group.bench_function("num-prime (this crate)", |b| {
         b.iter(|| -> num_bigint::BigUint { rng.gen_safe_prime(256) })
     });
+    // Note: num-primes uses thread_rng() internally, so this benchmark is not deterministic
     group.bench_function("num-primes", |b| b.iter(|| Generator::safe_prime(256)));
-    group.bench_function("glass_pumpkin", |b| b.iter(|| safe_gprime::new(256)));
+    let mut rng_gp = ChaCha8Rng::seed_from_u64(513);
+    group.bench_function("glass_pumpkin", |b| {
+        b.iter(|| safe_gprime::from_rng(256, &mut rng_gp))
+    });
     group.finish();
 }