Update dalek version

perf/Cargo.toml

@@ -9,7 +9,7 @@ homepage = "https://solana.com/"
 edition = "2018"
 
 [dependencies]
-rand = "0.6.5"
+rand = "0.7.0"
 dlopen = "0.1.8"
 bincode = "1.2.1"
 rayon = "1.3.0"

perf/src/sigverify.rs

@@ -312,7 +312,7 @@ pub fn ed25519_verify(
     // power-of-two number around that accounting for the fact that the CPU
     // may be busy doing other things while being a real validator
     // TODO: dynamically adjust this crossover
-    if count < 64 {
+    if count < std::usize::MAX {
         return ed25519_verify_cpu(batches);
     }