Merge pull request #40 from spacemeshos/parallel-k2-k3-pows

Find k2 and k3 PoWs in parallel for better speed

Author: poszu

benches/pow.rs

@@ -12,7 +12,22 @@ fn bench_k2_pow(c: &mut Criterion) {
                 b"hello world, CHALLENGE me!!!!!!!",
                 0,
                 ScryptParams::new(6, 0, 0),
-                black_box(0x0FFF_FFFF_FFFF_FFFF),
+                black_box(0x000F_FFFF_FFFF_FFFF),
+            )
+        })
+    });
+}
+
+fn bench_k3_pow(c: &mut Criterion) {
+    c.bench_function("k3_pow", |b| {
+        b.iter(|| {
+            post::pow::find_k3_pow(
+                b"hello world, CHALLENGE me!!!!!!!",
+                0,
+                &[0; 300],
+                ScryptParams::new(6, 0, 0),
+                black_box(0x000F_FFFF_FFFF_FFFF),
+                77,
             )
         })
     });
@@ -21,7 +36,7 @@ fn bench_k2_pow(c: &mut Criterion) {
 criterion_group!(
     name = benches;
     config = Criterion::default().with_profiler(PProfProfiler::new(1000, Output::Flamegraph(None)));
-    targets=bench_k2_pow
+    targets=bench_k2_pow,bench_k3_pow
 );
 
 criterion_main!(benches);

src/pow.rs

@@ -7,15 +7,14 @@
 //! without actually holding the whole POST data.
 //!
 //! TODO: explain the need for "K3 PoW".
+use rayon::prelude::{ParallelBridge, ParallelIterator};
 use scrypt_jane::scrypt::{scrypt, ScryptParams};
 
 pub fn find_k2_pow(challenge: &[u8; 32], nonce: u32, params: ScryptParams, difficulty: u64) -> u64 {
-    for k2_pow in 0u64.. {
-        if hash_k2_pow(challenge, nonce, params, k2_pow) < difficulty {
-            return k2_pow;
-        }
-    }
-    unreachable!()
+    (0u64..)
+        .par_bridge()
+        .find_any(|&k2_pow| hash_k2_pow(challenge, nonce, params, k2_pow) < difficulty)
+        .expect("looking for k2pow")
 }
 
 #[inline(always)]
@@ -33,20 +32,20 @@ pub(crate) fn hash_k2_pow(
     u64::from_le_bytes(output)
 }
 
-pub(crate) fn find_k3_pow(
+pub fn find_k3_pow(
     challenge: &[u8; 32],
     nonce: u32,
     indexes: &[u8],
     params: ScryptParams,
     difficulty: u64,
     k2_pow: u64,
 ) -> u64 {
-    for k3_pow in 0u64.. {
-        if hash_k3_pow(challenge, nonce, indexes, params, k2_pow, k3_pow) < difficulty {
-            return k3_pow;
-        }
-    }
-    unreachable!()
+    (0u64..)
+        .par_bridge()
+        .find_any(|&k3_pow| {
+            hash_k3_pow(challenge, nonce, indexes, params, k2_pow, k3_pow) < difficulty
+        })
+        .expect("looking for k3pow")
 }
 
 #[inline(always)]