Poh subsystem cleanup, genesis plumbing, enable real PoH on edge testnet (#4292)

* Remove unused PohServiceConfig::Step

* Clarify variable name

* Poh::hash() now takes an iteration counter

* man -> max

* Inline functions with single call site

* Move PohServiceConfig into GenesisBlock

* Add plumbing to enable real PoH on testnets

* Batch hashes to improve PoH hash rate

* Ensure a constant hashes_per_tick

* Remove PohEntry mixin field

* Poh/PohEntry no longer maintains tick_height

* Ensure a constant hashes_per_tick

* ci/localnet-sanity.sh: Use real PoH

* Rework Poh/PohService to keep PohRecorder unlocked as much as possible while hashing

sdk/src/genesis_block.rs

@@ -3,6 +3,7 @@
 use crate::account::Account;
 use crate::fee_calculator::FeeCalculator;
 use crate::hash::{hash, Hash};
+use crate::poh_config::PohConfig;
 use crate::pubkey::Pubkey;
 use crate::signature::{Keypair, KeypairUtil};
 use crate::system_program;
@@ -21,6 +22,7 @@ pub struct GenesisBlock {
     pub slots_per_epoch: u64,
     pub stakers_slot_offset: u64,
     pub ticks_per_slot: u64,
+    pub poh_config: PohConfig,
 }
 
 // useful for basic tests
@@ -54,6 +56,7 @@ impl GenesisBlock {
             slots_per_epoch: DEFAULT_SLOTS_PER_EPOCH,
             stakers_slot_offset: DEFAULT_SLOTS_PER_EPOCH,
             ticks_per_slot: DEFAULT_TICKS_PER_SLOT,
+            poh_config: PohConfig::default(),
         }
     }
 

sdk/src/lib.rs

@@ -10,6 +10,7 @@ pub mod loader_instruction;
 pub mod message;
 pub mod native_loader;
 pub mod packet;
+pub mod poh_config;
 pub mod pubkey;
 pub mod rpc_port;
 pub mod short_vec;

sdk/src/poh_config.rs

@@ -0,0 +1,29 @@
+use crate::timing::DEFAULT_NUM_TICKS_PER_SECOND;
+use std::time::Duration;
+
+#[derive(Serialize, Deserialize, Clone, Debug)]
+pub struct PohConfig {
+    /// The target tick rate of the cluster.
+    pub target_tick_duration: Duration,
+
+    /// How many hashes to roll before emitting the next tick entry.
+    /// None enables "Low power mode", which implies:
+    /// * sleep for `target_tick_duration` instead of hashing
+    /// * the number of hashes per tick will be variable
+    pub hashes_per_tick: Option<u64>,
+}
+
+impl PohConfig {
+    pub fn new_sleep(target_tick_duration: Duration) -> Self {
+        Self {
+            target_tick_duration,
+            hashes_per_tick: None,
+        }
+    }
+}
+
+impl Default for PohConfig {
+    fn default() -> Self {
+        Self::new_sleep(Duration::from_millis(1000 / DEFAULT_NUM_TICKS_PER_SECOND))
+    }
+}

sdk/src/timing.rs

@@ -2,7 +2,9 @@
 use std::time::Duration;
 use std::time::{SystemTime, UNIX_EPOCH};
 
-pub const NUM_TICKS_PER_SECOND: u64 = 10;
+// The default tick rate that the cluster attempts to achieve.  Note that the actual tick
+// rate at any given time should be expected to drift
+pub const DEFAULT_NUM_TICKS_PER_SECOND: u64 = 10;
 
 // At 10 ticks/s, 8 ticks per slot implies that leader rotation and voting will happen
 // every 800 ms. A fast voting cadence ensures faster finality and convergence