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[WIP] Difficulty Adjustment Updates (#651)

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* large updates for mining, fix async mode, will list changes in PR

* reset config and build defaults

* change to difficulty calculations

* tweaking mining params and tests

* tweaking to tests

* including pre-genesis data for difficulty adjustments, adding adjustment scenario tests

* further clarifying next_difficulty function

* moving tests out of consensus.rs

* pow test fix

* changing pre-genesis generation
This commit is contained in:
Yeastplume 2018-01-27 07:48:53 +00:00 committed by GitHub
parent 84128964fa
commit 783e4c250d
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GPG key ID: 4AEE18F83AFDEB23
14 changed files with 441 additions and 233 deletions
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2
chain/src/pipe.rs
View file

@ -210,7 +210,7 @@ fn validate_header(header: &BlockHeader, ctx: &mut BlockContext) -> Result<(), E
// explicit check to ensure we are not below the minimum difficulty // explicit check to ensure we are not below the minimum difficulty
// we will also check difficulty based on next_difficulty later on // we will also check difficulty based on next_difficulty later on
if header.difficulty < Difficulty::minimum() { if header.difficulty < Difficulty::one() {
return Err(Error::DifficultyTooLow); return Err(Error::DifficultyTooLow);
} }

5
chain/src/store.rs
View file

@ -231,11 +231,8 @@ impl Iterator for DifficultyIter {
fn next(&mut self) -> Option<Self::Item> { fn next(&mut self) -> Option<Self::Item> {
let bhe = self.store.get_block_header(&self.next); let bhe = self.store.get_block_header(&self.next);
match bhe { match bhe {
Err(e) => Some(Err(TargetError(e.to_string()))), Err(_) => None,
Ok(bh) => { Ok(bh) => {
if bh.height == 0 {
return None;
}
self.next = bh.previous; self.next = bh.previous;
Some(Ok((bh.timestamp.to_timespec().sec as u64, bh.difficulty))) Some(Ok((bh.timestamp.to_timespec().sec as u64, bh.difficulty)))
} }

2
chain/tests/store_indices.rs
View file

@ -53,7 +53,7 @@ fn test_various_store_indices() {
vec![], vec![],
&keychain, &keychain,
&key_id, &key_id,
Difficulty::minimum() Difficulty::one()
).unwrap(); ).unwrap();
let block_hash = block.hash(); let block_hash = block.hash();

8
chain/tests/test_coinbase_maturity.rs
View file

@ -80,7 +80,7 @@ fn test_coinbase_maturity() {
vec![], vec![],
&keychain, &keychain,
&key_id1, &key_id1,
Difficulty::minimum() Difficulty::one()
).unwrap(); ).unwrap();
block.header.timestamp = prev.timestamp + time::Duration::seconds(60); block.header.timestamp = prev.timestamp + time::Duration::seconds(60);
@ -131,7 +131,7 @@ fn test_coinbase_maturity() {
vec![&coinbase_txn], vec![&coinbase_txn],
&keychain, &keychain,
&key_id3, &key_id3,
Difficulty::minimum(), Difficulty::one(),
).unwrap(); ).unwrap();
block.header.timestamp = prev.timestamp + time::Duration::seconds(60); block.header.timestamp = prev.timestamp + time::Duration::seconds(60);
@ -163,7 +163,7 @@ fn test_coinbase_maturity() {
vec![], vec![],
&keychain, &keychain,
&pk, &pk,
Difficulty::minimum() Difficulty::one()
).unwrap(); ).unwrap();
block.header.timestamp = prev.timestamp + time::Duration::seconds(60); block.header.timestamp = prev.timestamp + time::Duration::seconds(60);
@ -197,7 +197,7 @@ fn test_coinbase_maturity() {
vec![&coinbase_txn], vec![&coinbase_txn],
&keychain, &keychain,
&key_id4, &key_id4,
Difficulty::minimum(), Difficulty::one(),
).unwrap(); ).unwrap();
block.header.timestamp = prev.timestamp + time::Duration::seconds(60); block.header.timestamp = prev.timestamp + time::Duration::seconds(60);

258
core/src/consensus.rs
View file

@ -1,5 +1,4 @@
// Copyright 2016 The Grin Developers // Copyright 2018 The Grin Developers
//
// Licensed under the Apache License, Version 2.0 (the "License"); // Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License. // you may not use this file except in compliance with the License.
// You may obtain a copy of the License at // You may obtain a copy of the License at
@ -23,6 +22,7 @@ use std::fmt;
use std::cmp::max; use std::cmp::max;
use core::target::Difficulty; use core::target::Difficulty;
use global;
/// A grin is divisible to 10^9, following the SI prefixes /// A grin is divisible to 10^9, following the SI prefixes
pub const GRIN_BASE: u64 = 1_000_000_000; pub const GRIN_BASE: u64 = 1_000_000_000;
@ -128,23 +128,33 @@ pub fn valid_header_version(height: u64, version: u16) -> bool {
} }
} }
/// The minimum mining difficulty we'll allow
pub const MINIMUM_DIFFICULTY: u64 = 1;
/// Time window in blocks to calculate block time median /// Time window in blocks to calculate block time median
pub const MEDIAN_TIME_WINDOW: u64 = 11; pub const MEDIAN_TIME_WINDOW: u64 = 11;
/// Index at half the desired median
pub const MEDIAN_TIME_INDEX: u64 = MEDIAN_TIME_WINDOW / 2;
/// Number of blocks used to calculate difficulty adjustments /// Number of blocks used to calculate difficulty adjustments
pub const DIFFICULTY_ADJUST_WINDOW: u64 = 23; pub const DIFFICULTY_ADJUST_WINDOW: u64 = 60;
/// Average time span of the difficulty adjustment window /// Average time span of the difficulty adjustment window
pub const BLOCK_TIME_WINDOW: u64 = DIFFICULTY_ADJUST_WINDOW * BLOCK_TIME_SEC; pub const BLOCK_TIME_WINDOW: u64 = DIFFICULTY_ADJUST_WINDOW * BLOCK_TIME_SEC;
/// Maximum size time window used for difficulty adjustments /// Maximum size time window used for difficulty adjustments
pub const UPPER_TIME_BOUND: u64 = BLOCK_TIME_WINDOW * 4 / 3; pub const UPPER_TIME_BOUND: u64 = BLOCK_TIME_WINDOW * 2;
/// Minimum size time window used for difficulty adjustments /// Minimum size time window used for difficulty adjustments
pub const LOWER_TIME_BOUND: u64 = BLOCK_TIME_WINDOW * 5 / 6; pub const LOWER_TIME_BOUND: u64 = BLOCK_TIME_WINDOW / 2;
/// Dampening factor to use for difficulty adjustment
pub const DAMP_FACTOR: u64 = 3;
/// The initial difficulty at launch. This should be over-estimated
/// and difficulty should come down at launch rather than up
/// Currently grossly over-estimated at 10% of current
/// ethereum GPUs (assuming 1GPU can solve a block at diff 1
/// in one block interval)
pub const INITIAL_DIFFICULTY: u64 = 1_000_000;
/// Consensus errors /// Consensus errors
#[derive(Clone, Debug, PartialEq)] #[derive(Clone, Debug, PartialEq)]
@ -171,57 +181,58 @@ impl fmt::Display for TargetError {
/// The difficulty calculation is based on both Digishield and GravityWave /// The difficulty calculation is based on both Digishield and GravityWave
/// family of difficulty computation, coming to something very close to Zcash. /// family of difficulty computation, coming to something very close to Zcash.
/// The refence difficulty is an average of the difficulty over a window of /// The refence difficulty is an average of the difficulty over a window of
/// 23 blocks. The corresponding timespan is calculated by using the /// DIFFICULTY_ADJUST_WINDOW blocks. The corresponding timespan is calculated
/// difference between the median timestamps at the beginning and the end /// by using the difference between the median timestamps at the beginning
/// of the window. /// and the end of the window.
pub fn next_difficulty<T>(cursor: T) -> Result<Difficulty, TargetError> pub fn next_difficulty<T>(cursor: T) -> Result<Difficulty, TargetError>
where where
T: IntoIterator<Item = Result<(u64, Difficulty), TargetError>>, T: IntoIterator<Item = Result<(u64, Difficulty), TargetError>>,
{ {
// Block times at the begining and end of the adjustment window, used to // Create vector of difficulty data running from earliest
// calculate medians later. // to latest, and pad with simulated pre-genesis data to allow earlier
let mut window_begin = vec![]; // adjustment if there isn't enough window data
let mut window_end = vec![]; // length will be DIFFICULTY_ADJUST_WINDOW+MEDIAN_TIME_WINDOW
let diff_data = global::difficulty_data_to_vector(cursor);
// Get the difficulty sum for averaging later
// Which in this case is the sum of the last
// DIFFICULTY_ADJUST_WINDOW elements
let diff_sum = diff_data.iter()
.skip(MEDIAN_TIME_WINDOW as usize)
.take(DIFFICULTY_ADJUST_WINDOW as usize)
.fold(Difficulty::zero(), |sum, d| sum + d.clone().unwrap().1);
// Sum of difficulties in the window, used to calculate the average later. // Obtain the median window for the earlier time period
let mut diff_sum = Difficulty::zero(); // which is just the first MEDIAN_TIME_WINDOW elements
let mut window_earliest: Vec<u64> = diff_data.iter()
.take(MEDIAN_TIME_WINDOW as usize)
.map(|n| n.clone().unwrap().0)
.collect();
// Enumerating backward over blocks // Obtain the median window for the latest time period
for (n, head_info) in cursor.into_iter().enumerate() { // i.e. the last MEDIAN_TIME_WINDOW elements
let m = n as u64; let mut window_latest: Vec<u64> = diff_data.iter()
let (ts, diff) = head_info?; .skip(DIFFICULTY_ADJUST_WINDOW as usize)
.map(|n| n.clone().unwrap().0)
.collect();
// Sum each element in the adjustment window. In addition, retain // And obtain our median values
// timestamps within median windows (at ]start;start-11] and ]end;end-11] window_earliest.sort();
// to later calculate medians. window_latest.sort();
if m < DIFFICULTY_ADJUST_WINDOW { let latest_ts = window_latest[MEDIAN_TIME_INDEX as usize];
diff_sum = diff_sum + diff; let earliest_ts = window_earliest[MEDIAN_TIME_INDEX as usize];
if m < MEDIAN_TIME_WINDOW { // Calculate the average difficulty
window_begin.push(ts); let diff_avg = diff_sum.into_num() /
} Difficulty::from_num(DIFFICULTY_ADJUST_WINDOW).into_num();
} else if m < DIFFICULTY_ADJUST_WINDOW + MEDIAN_TIME_WINDOW {
window_end.push(ts);
} else {
break;
}
}
// Check we have enough blocks // Actual undampened time delta
if window_end.len() < (MEDIAN_TIME_WINDOW as usize) { let ts_delta = latest_ts - earliest_ts;
return Ok(Difficulty::minimum());
}
// Calculating time medians at the beginning and end of the window. // Apply dampening
window_begin.sort(); let ts_damp = match diff_avg {
window_end.sort(); n if n >= DAMP_FACTOR => ((DAMP_FACTOR-1) * BLOCK_TIME_WINDOW + ts_delta) / DAMP_FACTOR,
let begin_ts = window_begin[window_begin.len() / 2]; _ => ts_delta,
let end_ts = window_end[window_end.len() / 2]; };
// Average difficulty and dampened average time
let diff_avg = diff_sum.into_num() as f64 /
Difficulty::from_num(DIFFICULTY_ADJUST_WINDOW).into_num() as f64;
let ts_damp = (3 * BLOCK_TIME_WINDOW + (begin_ts - end_ts)) / 4;
// Apply time bounds // Apply time bounds
let adj_ts = if ts_damp < LOWER_TIME_BOUND { let adj_ts = if ts_damp < LOWER_TIME_BOUND {
@ -233,11 +244,10 @@ where
}; };
let difficulty = let difficulty =
diff_avg * Difficulty::from_num(BLOCK_TIME_WINDOW).into_num() as f64 diff_avg * Difficulty::from_num(BLOCK_TIME_WINDOW).into_num()
/ Difficulty::from_num(adj_ts).into_num() as f64; / Difficulty::from_num(adj_ts).into_num();
// All this ceil and f64 business is so that difficulty can always adjust
// for smaller numbers < 10 Ok(max(Difficulty::from_num(difficulty), Difficulty::one()))
Ok(max(Difficulty::from_num(difficulty.ceil() as u64), Difficulty::minimum()))
} }
/// Consensus rule that collections of items are sorted lexicographically. /// Consensus rule that collections of items are sorted lexicographically.
@ -245,143 +255,3 @@ pub trait VerifySortOrder<T> {
/// Verify a collection of items is sorted as required. /// Verify a collection of items is sorted as required.
fn verify_sort_order(&self) -> Result<(), Error>; fn verify_sort_order(&self) -> Result<(), Error>;
} }
#[cfg(test)]
use std;
#[cfg(test)]
mod test {
use core::target::Difficulty;
use super::*;
// Builds an iterator for next difficulty calculation with the provided
// constant time interval, difficulty and total length.
fn repeat(interval: u64, diff: u64, len: u64) -> Vec<Result<(u64, Difficulty), TargetError>> {
// watch overflow here, length shouldn't be ridiculous anyhow
assert!(len < std::usize::MAX as u64);
let diffs = vec![Difficulty::from_num(diff); len as usize];
let times = (0..(len as usize)).map(|n| n * interval as usize).rev();
let pairs = times.zip(diffs.iter());
pairs
.map(|(t, d)| Ok((t as u64, d.clone())))
.collect::<Vec<_>>()
}
fn repeat_offs(
from: u64,
interval: u64,
diff: u64,
len: u64,
) -> Vec<Result<(u64, Difficulty), TargetError>> {
map_vec!(repeat(interval, diff, len), |e| match e.clone() {
Err(e) => Err(e),
Ok((t, d)) => Ok((t + from, d)),
})
}
/// Checks different next_target adjustments and difficulty boundaries
#[test]
fn next_target_adjustment() {
// not enough data
assert_eq!(
next_difficulty(vec![]).unwrap(),
Difficulty::from_num(MINIMUM_DIFFICULTY)
);
assert_eq!(
next_difficulty(vec![Ok((60, Difficulty::one()))]).unwrap(),
Difficulty::from_num(MINIMUM_DIFFICULTY)
);
assert_eq!(
next_difficulty(repeat(60, 10, DIFFICULTY_ADJUST_WINDOW)).unwrap(),
Difficulty::from_num(MINIMUM_DIFFICULTY)
);
// just enough data, right interval, should stay constant
let just_enough = DIFFICULTY_ADJUST_WINDOW + MEDIAN_TIME_WINDOW;
assert_eq!(
next_difficulty(repeat(60, 1000, just_enough)).unwrap(),
Difficulty::from_num(1000)
);
// checking averaging works, window length is odd so need to compensate a little
let sec = DIFFICULTY_ADJUST_WINDOW / 2 + 1 + MEDIAN_TIME_WINDOW;
let mut s1 = repeat(60, 500, sec);
let mut s2 = repeat_offs((sec * 60) as u64, 60, 1545, DIFFICULTY_ADJUST_WINDOW / 2);
s2.append(&mut s1);
assert_eq!(next_difficulty(s2).unwrap(), Difficulty::from_num(1000));
// too slow, diff goes down
assert_eq!(
next_difficulty(repeat(90, 1000, just_enough)).unwrap(),
Difficulty::from_num(890)
);
assert_eq!(
next_difficulty(repeat(120, 1000, just_enough)).unwrap(),
Difficulty::from_num(800)
);
// too fast, diff goes up
assert_eq!(
next_difficulty(repeat(55, 1000, just_enough)).unwrap(),
Difficulty::from_num(1022)
);
assert_eq!(
next_difficulty(repeat(45, 1000, just_enough)).unwrap(),
Difficulty::from_num(1068)
);
// hitting lower time bound, should always get the same result below
assert_eq!(
next_difficulty(repeat(20, 1000, just_enough)).unwrap(),
Difficulty::from_num(1200)
);
assert_eq!(
next_difficulty(repeat(10, 1000, just_enough)).unwrap(),
Difficulty::from_num(1200)
);
// hitting higher time bound, should always get the same result above
assert_eq!(
next_difficulty(repeat(160, 1000, just_enough)).unwrap(),
Difficulty::from_num(750)
);
assert_eq!(
next_difficulty(repeat(200, 1000, just_enough)).unwrap(),
Difficulty::from_num(750)
);
// We should never drop below MINIMUM_DIFFICULTY (1)
assert_eq!(
next_difficulty(repeat(90, 0, just_enough)).unwrap(),
Difficulty::from_num(1)
);
}
#[test]
fn hard_fork_1() {
assert!(valid_header_version(0, 1));
assert!(valid_header_version(10, 1));
assert!(!valid_header_version(10, 2));
assert!(valid_header_version(250_000, 1));
assert!(!valid_header_version(250_001, 1));
assert!(!valid_header_version(500_000, 1));
assert!(!valid_header_version(250_001, 2));
}
// #[test]
// fn hard_fork_2() {
// assert!(valid_header_version(0, 1));
// assert!(valid_header_version(10, 1));
// assert!(valid_header_version(10, 2));
// assert!(valid_header_version(250_000, 1));
// assert!(!valid_header_version(250_001, 1));
// assert!(!valid_header_version(500_000, 1));
// assert!(valid_header_version(250_001, 2));
// assert!(valid_header_version(500_000, 2));
// assert!(!valid_header_version(500_001, 2));
// }
}

8
core/src/core/block.rs
View file

@ -33,7 +33,7 @@ use core::{
COINBASE_OUTPUT COINBASE_OUTPUT
}; };
use consensus; use consensus;
use consensus::{exceeds_weight, reward, MINIMUM_DIFFICULTY, REWARD, VerifySortOrder}; use consensus::{exceeds_weight, reward, REWARD, VerifySortOrder};
use core::hash::{Hash, Hashed, ZERO_HASH}; use core::hash::{Hash, Hashed, ZERO_HASH};
use core::id::ShortIdentifiable; use core::id::ShortIdentifiable;
use core::target::Difficulty; use core::target::Difficulty;
@ -140,8 +140,8 @@ impl Default for BlockHeader {
height: 0, height: 0,
previous: ZERO_HASH, previous: ZERO_HASH,
timestamp: time::at_utc(time::Timespec { sec: 0, nsec: 0 }), timestamp: time::at_utc(time::Timespec { sec: 0, nsec: 0 }),
difficulty: Difficulty::from_num(MINIMUM_DIFFICULTY), difficulty: Difficulty::one(),
total_difficulty: Difficulty::from_num(MINIMUM_DIFFICULTY), total_difficulty: Difficulty::one(),
utxo_root: ZERO_HASH, utxo_root: ZERO_HASH,
range_proof_root: ZERO_HASH, range_proof_root: ZERO_HASH,
kernel_root: ZERO_HASH, kernel_root: ZERO_HASH,
@ -851,7 +851,7 @@ mod test {
txs, txs,
keychain, keychain,
&key_id, &key_id,
Difficulty::minimum() Difficulty::one()
).unwrap() ).unwrap()
} }

10
core/src/core/mod.rs
View file

@ -396,7 +396,7 @@ mod test {
vec![], vec![],
&keychain, &keychain,
&key_id, &key_id,
Difficulty::minimum(), Difficulty::one(),
).unwrap(); ).unwrap();
b.cut_through().validate().unwrap(); b.cut_through().validate().unwrap();
} }
@ -414,7 +414,7 @@ mod test {
vec![&mut tx1], vec![&mut tx1],
&keychain, &keychain,
&key_id, &key_id,
Difficulty::minimum(), Difficulty::one(),
).unwrap(); ).unwrap();
b.cut_through().validate().unwrap(); b.cut_through().validate().unwrap();
} }
@ -432,7 +432,7 @@ mod test {
vec![&mut tx1, &mut tx2], vec![&mut tx1, &mut tx2],
&keychain, &keychain,
&key_id, &key_id,
Difficulty::minimum(), Difficulty::one(),
).unwrap(); ).unwrap();
b.validate().unwrap(); b.validate().unwrap();
} }
@ -463,7 +463,7 @@ mod test {
vec![&tx1], vec![&tx1],
&keychain, &keychain,
&key_id3.clone(), &key_id3.clone(),
Difficulty::minimum(), Difficulty::one(),
).unwrap(); ).unwrap();
b.validate().unwrap(); b.validate().unwrap();
@ -484,7 +484,7 @@ mod test {
vec![&tx1], vec![&tx1],
&keychain, &keychain,
&key_id3.clone(), &key_id3.clone(),
Difficulty::minimum(), Difficulty::one(),
).unwrap(); ).unwrap();
match b.validate() { match b.validate() {
Err(KernelLockHeight(height)) => { Err(KernelLockHeight(height)) => {

8
core/src/core/target.rs
View file

@ -25,10 +25,8 @@ use std::ops::{Add, Div, Mul, Sub};
use serde::{de, Deserialize, Deserializer, Serialize, Serializer}; use serde::{de, Deserialize, Deserializer, Serialize, Serializer};
use byteorder::{BigEndian, ByteOrder}; use byteorder::{BigEndian, ByteOrder};
use consensus;
use core::hash::Hash; use core::hash::Hash;
use ser::{self, Readable, Reader, Writeable, Writer}; use ser::{self, Readable, Reader, Writeable, Writer};
use util::logger::LOGGER;
use core::global; use core::global;
@ -52,11 +50,6 @@ impl Difficulty {
Difficulty { num: 1 } Difficulty { num: 1 }
} }
/// Minimum difficulty according to our consensus rules.
pub fn minimum() -> Difficulty {
Difficulty { num: consensus::MINIMUM_DIFFICULTY }
}
/// Convert a `u32` into a `Difficulty` /// Convert a `u32` into a `Difficulty`
pub fn from_num(num: u64) -> Difficulty { pub fn from_num(num: u64) -> Difficulty {
Difficulty { num: num } Difficulty { num: num }
@ -70,7 +63,6 @@ impl Difficulty {
let mut in_vec = h.to_vec(); let mut in_vec = h.to_vec();
in_vec.truncate(8); in_vec.truncate(8);
let num = BigEndian::read_u64(&in_vec); let num = BigEndian::read_u64(&in_vec);
trace!(LOGGER, "Calculated difficulty: {}", max_target as f64 / num as f64);
Difficulty { num: max_target / num } Difficulty { num: max_target / num }
} }

7
core/src/genesis.rs
View file

@ -89,6 +89,9 @@ pub fn genesis_testnet2() -> core::Block {
tm_hour: 20, tm_hour: 20,
..time::empty_tm() ..time::empty_tm()
}, },
//TODO: Check this is over-estimated at T2 launch
difficulty: Difficulty::from_num(global::initial_block_difficulty()),
total_difficulty: Difficulty::from_num(global::initial_block_difficulty()),
nonce: 70081, nonce: 70081,
pow: core::Proof::new(vec![0x43ee48, 0x18d5a49, 0x2b76803, 0x3181a29, 0x39d6a8a, 0x39ef8d8, pow: core::Proof::new(vec![0x43ee48, 0x18d5a49, 0x2b76803, 0x3181a29, 0x39d6a8a, 0x39ef8d8,
0x478a0fb, 0x69c1f9e, 0x6da4bca, 0x6f8782c, 0x9d842d7, 0xa051397, 0x478a0fb, 0x69c1f9e, 0x6da4bca, 0x6f8782c, 0x9d842d7, 0xa051397,
@ -118,8 +121,8 @@ pub fn genesis_main() -> core::Block {
tm_mday: 14, tm_mday: 14,
..time::empty_tm() ..time::empty_tm()
}, },
difficulty: Difficulty::from_num(1000), difficulty: Difficulty::from_num(global::initial_block_difficulty()),
total_difficulty: Difficulty::from_num(1000), total_difficulty: Difficulty::from_num(global::initial_block_difficulty()),
nonce: global::get_genesis_nonce(), nonce: global::get_genesis_nonce(),
pow: core::Proof::zero(consensus::PROOFSIZE), pow: core::Proof::zero(consensus::PROOFSIZE),
..Default::default() ..Default::default()

83
core/src/global.rs
View file

@ -1,4 +1,4 @@
// Copyright 2017 The Grin Developers // Copyright 2018 The Grin Developers
// //
// Licensed under the Apache License, Version 2.0 (the "License"); // Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License. // you may not use this file except in compliance with the License.
@ -25,6 +25,10 @@ use std::sync::RwLock;
use consensus::PROOFSIZE; use consensus::PROOFSIZE;
use consensus::DEFAULT_SIZESHIFT; use consensus::DEFAULT_SIZESHIFT;
use consensus::COINBASE_MATURITY; use consensus::COINBASE_MATURITY;
use consensus::{MEDIAN_TIME_WINDOW, INITIAL_DIFFICULTY,
BLOCK_TIME_SEC, DIFFICULTY_ADJUST_WINDOW};
use core::target::Difficulty;
use consensus::TargetError;
/// Define these here, as they should be developer-set, not really tweakable /// Define these here, as they should be developer-set, not really tweakable
/// by users /// by users
@ -47,6 +51,14 @@ pub const AUTOMATED_TESTING_COINBASE_MATURITY: u64 = 3;
/// User testing coinbase maturity /// User testing coinbase maturity
pub const USER_TESTING_COINBASE_MATURITY: u64 = 3; pub const USER_TESTING_COINBASE_MATURITY: u64 = 3;
/// Testing initial block difficulty
pub const TESTING_INITIAL_DIFFICULTY: u64 = 1;
/// Testing initial block difficulty, testnet 2
/// we want to overestimate here as well
/// Setting to 1 for development, but should be 1000 at T2 launch
pub const TESTNET2_INITIAL_DIFFICULTY: u64 = 1;
/// The target is the 32-bytes hash block hashes must be lower than. /// The target is the 32-bytes hash block hashes must be lower than.
pub const MAX_PROOF_TARGET: [u8; 8] = [0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff]; pub const MAX_PROOF_TARGET: [u8; 8] = [0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff];
@ -139,6 +151,18 @@ pub fn max_proof_target() -> [u8; 8] {
} }
} }
/// Initial mining difficulty
pub fn initial_block_difficulty() -> u64 {
let param_ref = CHAIN_TYPE.read().unwrap();
match *param_ref {
ChainTypes::AutomatedTesting => TESTING_INITIAL_DIFFICULTY,
ChainTypes::UserTesting => TESTING_INITIAL_DIFFICULTY,
ChainTypes::Testnet1 => TESTING_INITIAL_DIFFICULTY,
ChainTypes::Testnet2 => TESTNET2_INITIAL_DIFFICULTY,
ChainTypes::Mainnet => INITIAL_DIFFICULTY,
}
}
/// Are we in automated testing mode? /// Are we in automated testing mode?
pub fn is_automated_testing_mode() -> bool { pub fn is_automated_testing_mode() -> bool {
let param_ref = CHAIN_TYPE.read().unwrap(); let param_ref = CHAIN_TYPE.read().unwrap();
@ -162,8 +186,7 @@ pub fn is_production_mode() -> bool {
/// Helper function to get a nonce known to create a valid POW on /// Helper function to get a nonce known to create a valid POW on
/// the genesis block, to prevent it taking ages. Should be fine for now /// the genesis block, to prevent it taking ages. Should be fine for now
/// as the genesis block POW solution turns out to be the same for every new /// as the genesis block POW solution turns out to be the same for every new
/// block chain /// block chain at the moment
/// at the moment
pub fn get_genesis_nonce() -> u64 { pub fn get_genesis_nonce() -> u64 {
let param_ref = CHAIN_TYPE.read().unwrap(); let param_ref = CHAIN_TYPE.read().unwrap();
match *param_ref { match *param_ref {
@ -176,3 +199,57 @@ pub fn get_genesis_nonce() -> u64 {
_ => panic!("Pre-set"), _ => panic!("Pre-set"),
} }
} }
/// Converts an iterator of block difficulty data to more a more mangeable vector and pads
/// if needed (which will) only be needed for the first few blocks after genesis
pub fn difficulty_data_to_vector<T>(cursor: T) -> Vec<Result<(u64, Difficulty), TargetError>>
where
T: IntoIterator<Item = Result<(u64, Difficulty), TargetError>> {
// Convert iterator to vector, so we can append to it if necessary
let needed_block_count = (MEDIAN_TIME_WINDOW + DIFFICULTY_ADJUST_WINDOW) as usize;
let mut last_n: Vec<Result<(u64, Difficulty), TargetError>> = cursor.into_iter()
.take(needed_block_count)
.collect();
// Sort blocks from earliest to latest (to keep conceptually easier)
last_n.reverse();
// Only needed just after blockchain launch... basically ensures there's
// always enough data by simulating perfectly timed pre-genesis
// blocks at the genesis difficulty as needed.
let block_count_difference = needed_block_count - last_n.len();
if block_count_difference > 0 {
// Collect any real data we have
let mut live_intervals:Vec<(u64, Difficulty)> = last_n.iter()
.map(|b| (b.clone().unwrap().0, b.clone().unwrap().1))
.collect();
for i in (1..live_intervals.len()).rev() {
live_intervals[i].0=live_intervals[i].0-live_intervals[i-1].0;
}
//
// Remove genesis "interval"
if live_intervals.len() > 1 {
live_intervals.remove(0);
} else {
//if it's just genesis, adjust the interval
live_intervals[0].0 = BLOCK_TIME_SEC;
}
let mut interval_index = live_intervals.len() - 1;
let mut last_ts = last_n.first().as_ref().unwrap().as_ref().unwrap().0;
// fill in simulated blocks, repeating whatever pattern we've obtained from
// real data
// if we have, say, 15 blocks so far with intervals of I1..I15, then
// the 71-15=56 pre genesis blocks will have
// intervals/difficulties I1..I15 I1..I15 I1..I15 I1..I11
for _ in 0..block_count_difference {
last_ts = last_ts - live_intervals[interval_index].0;
let last_diff = &live_intervals[interval_index].1;
last_n.insert(0, Ok((last_ts, last_diff.clone())));
interval_index = match interval_index {
0 => live_intervals.len()-1,
_ => interval_index - 1,
};
}
}
last_n
}

270
core/tests/consensus.rs Normal file
View file

@ -0,0 +1,270 @@
// Copyright 2018 The Grin Developers
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//! core consensus.rs tests (separated to de-clutter consensus.rs)
#[macro_use]
extern crate grin_core as core;
extern crate time;
use core::core::target::Difficulty;
use core::global;
use core::consensus::*;
// Builds an iterator for next difficulty calculation with the provided
// constant time interval, difficulty and total length.
fn repeat(interval: u64, diff: u64, len: u64, cur_time:Option<u64>) -> Vec<Result<(u64, Difficulty), TargetError>> {
let cur_time = match cur_time {
Some(t) => t,
None => time::get_time().sec as u64,
};
// watch overflow here, length shouldn't be ridiculous anyhow
assert!(len < std::usize::MAX as u64);
let diffs = vec![Difficulty::from_num(diff); len as usize];
let times = (0..(len as usize)).map(|n| n * interval as usize).rev();
let pairs = times.zip(diffs.iter());
pairs
.map(|(t, d)| Ok((cur_time + t as u64, d.clone())))
.collect::<Vec<_>>()
}
// Creates a new chain with a genesis at a simulated difficulty
fn create_chain_sim(diff: u64) -> Vec<Result<(u64, Difficulty), TargetError>> {
vec![Ok((time::get_time().sec as u64, Difficulty::from_num(diff)))]
}
// Adds another 'block' to the iterator, so to speak, with difficulty calculated
// from the difficulty adjustment at interval seconds from the previous block
fn add_block(interval: u64, chain_sim: Vec<Result<(u64, Difficulty), TargetError>>)
-> Vec<Result<(u64, Difficulty), TargetError>> {
let mut return_chain = chain_sim.clone();
// get last interval
let last_elem = chain_sim.first().as_ref().unwrap().as_ref().unwrap();
return_chain.insert(0, Ok((last_elem.0+interval, last_elem.clone().1)));
let diff = next_difficulty(return_chain.clone()).unwrap();
return_chain[0]=Ok((last_elem.0+interval, diff));
return_chain
}
// Adds another n 'blocks' to the iterator, with difficulty calculated
fn add_block_repeated(interval: u64, chain_sim: Vec<Result<(u64, Difficulty), TargetError>>, iterations: usize)
-> Vec<Result<(u64, Difficulty), TargetError>> {
let mut return_chain = chain_sim.clone();
for _ in 0..iterations {
return_chain = add_block(interval, return_chain.clone());
}
return_chain
}
// Prints the contents of the iterator and its difficulties.. useful for tweaking
fn print_chain_sim(chain_sim: &Vec<Result<(u64, Difficulty), TargetError>>) {
let mut chain_sim=chain_sim.clone();
chain_sim.reverse();
let mut last_time=0;
chain_sim.iter()
.enumerate()
.for_each(|(i, b)| {
let block = b.as_ref().unwrap();
println!("Height: {}, Time: {}, Interval: {}, Next network difficulty:{}",
i, block.0, block.0-last_time, block.1);
last_time=block.0;
});
}
fn repeat_offs(
from: u64,
interval: u64,
diff: u64,
len: u64,
) -> Vec<Result<(u64, Difficulty), TargetError>> {
map_vec!(repeat(interval, diff, len, Some(from)), |e| match e.clone() {
Err(e) => Err(e),
Ok((t, d)) => Ok((t, d)),
})
}
/// Checks different next_target adjustments and difficulty boundaries
#[test]
fn adjustment_scenarios() {
// Use production parameters for genesis diff
global::set_mining_mode(global::ChainTypes::Mainnet);
// Genesis block with initial diff
let chain_sim = create_chain_sim(global::initial_block_difficulty());
// Scenario 1) Hash power is massively over estimated, first block takes an hour
let chain_sim = add_block_repeated(3600, chain_sim, 2);
let chain_sim = add_block_repeated(1800, chain_sim, 2);
let chain_sim = add_block_repeated(900, chain_sim, 10);
println!("*********************************************************");
println!("Scenario 1) Grossly over-estimated genesis difficulty ");
println!("*********************************************************");
print_chain_sim(&chain_sim);
println!("*********************************************************");
// Under-estimated difficulty
let chain_sim = create_chain_sim(global::initial_block_difficulty());
let chain_sim = add_block_repeated(1, chain_sim, 5);
let chain_sim = add_block_repeated(20, chain_sim, 5);
println!("*********************************************************");
println!("Scenario 2) Grossly under-estimated genesis difficulty ");
println!("*********************************************************");
print_chain_sim(&chain_sim);
println!("*********************************************************");
let just_enough = (DIFFICULTY_ADJUST_WINDOW + MEDIAN_TIME_WINDOW) as usize;
// Steady difficulty for a good while, then a sudden drop
let chain_sim = create_chain_sim(global::initial_block_difficulty());
let chain_sim = add_block_repeated(10, chain_sim, just_enough as usize);
let chain_sim = add_block_repeated(600, chain_sim, 10);
println!("");
println!("*********************************************************");
println!("Scenario 3) Sudden drop in hashpower");
println!("*********************************************************");
print_chain_sim(&chain_sim);
println!("*********************************************************");
// Sudden increase
let chain_sim = create_chain_sim(global::initial_block_difficulty());
let chain_sim = add_block_repeated(60, chain_sim, just_enough as usize);
let chain_sim = add_block_repeated(10, chain_sim, 10);
println!("");
println!("*********************************************************");
println!("Scenario 4) Sudden increase in hashpower");
println!("*********************************************************");
print_chain_sim(&chain_sim);
println!("*********************************************************");
// Oscillations
let chain_sim = create_chain_sim(global::initial_block_difficulty());
let chain_sim = add_block_repeated(60, chain_sim, just_enough as usize);
let chain_sim = add_block_repeated(10, chain_sim, 10);
let chain_sim = add_block_repeated(60, chain_sim, 20);
let chain_sim = add_block_repeated(10, chain_sim, 10);
println!("");
println!("*********************************************************");
println!("Scenario 5) Oscillations in hashpower");
println!("*********************************************************");
print_chain_sim(&chain_sim);
println!("*********************************************************");
}
/// Checks different next_target adjustments and difficulty boundaries
#[test]
fn next_target_adjustment() {
global::set_mining_mode(global::ChainTypes::AutomatedTesting);
let cur_time = time::get_time().sec as u64;
assert_eq!(
next_difficulty(vec![Ok((cur_time, Difficulty::one()))]).unwrap(),
Difficulty::one()
);
assert_eq!(
next_difficulty(repeat(60, 1, DIFFICULTY_ADJUST_WINDOW, None)).unwrap(),
Difficulty::one()
);
// Check we don't get stuck on difficulty 1
assert_ne!(
next_difficulty(repeat(1, 10, DIFFICULTY_ADJUST_WINDOW, None)).unwrap(),
Difficulty::one()
);
// just enough data, right interval, should stay constant
let just_enough = DIFFICULTY_ADJUST_WINDOW + MEDIAN_TIME_WINDOW;
assert_eq!(
next_difficulty(repeat(60, 1000, just_enough, None)).unwrap(),
Difficulty::from_num(1000)
);
// checking averaging works
let sec = DIFFICULTY_ADJUST_WINDOW / 2 + MEDIAN_TIME_WINDOW;
let mut s1 = repeat(60, 500, sec, Some(cur_time));
let mut s2 = repeat_offs(cur_time+(sec * 60) as u64, 60, 1500, DIFFICULTY_ADJUST_WINDOW / 2);
s2.append(&mut s1);
assert_eq!(next_difficulty(s2).unwrap(), Difficulty::from_num(1000));
// too slow, diff goes down
assert_eq!(
next_difficulty(repeat(90, 1000, just_enough, None)).unwrap(),
Difficulty::from_num(857)
);
assert_eq!(
next_difficulty(repeat(120, 1000, just_enough, None)).unwrap(),
Difficulty::from_num(750)
);
// too fast, diff goes up
assert_eq!(
next_difficulty(repeat(55, 1000, just_enough, None)).unwrap(),
Difficulty::from_num(1028)
);
assert_eq!(
next_difficulty(repeat(45, 1000, just_enough, None)).unwrap(),
Difficulty::from_num(1090)
);
// hitting lower time bound, should always get the same result below
assert_eq!(
next_difficulty(repeat(0, 1000, just_enough, None)).unwrap(),
Difficulty::from_num(1500)
);
assert_eq!(
next_difficulty(repeat(0, 1000, just_enough, None)).unwrap(),
Difficulty::from_num(1500)
);
// hitting higher time bound, should always get the same result above
assert_eq!(
next_difficulty(repeat(300, 1000, just_enough, None)).unwrap(),
Difficulty::from_num(500)
);
assert_eq!(
next_difficulty(repeat(400, 1000, just_enough, None)).unwrap(),
Difficulty::from_num(500)
);
// We should never drop below 1
assert_eq!(
next_difficulty(repeat(90, 0, just_enough, None)).unwrap(),
Difficulty::from_num(1)
);
}
#[test]
fn hard_fork_1() {
assert!(valid_header_version(0, 1));
assert!(valid_header_version(10, 1));
assert!(!valid_header_version(10, 2));
assert!(valid_header_version(250_000, 1));
assert!(!valid_header_version(250_001, 1));
assert!(!valid_header_version(500_000, 1));
assert!(!valid_header_version(250_001, 2));
}
// #[test]
// fn hard_fork_2() {
// assert!(valid_header_version(0, 1));
// assert!(valid_header_version(10, 1));
// assert!(valid_header_version(10, 2));
// assert!(valid_header_version(250_000, 1));
// assert!(!valid_header_version(250_001, 1));
// assert!(!valid_header_version(500_000, 1));
// assert!(valid_header_version(250_001, 2));
// assert!(valid_header_version(500_000, 2));
// assert!(!valid_header_version(500_001, 2));
// }

2
grin/src/miner.rs
View file

@ -604,7 +604,7 @@ impl Miner {
b.inputs.len(), b.inputs.len(),
b.outputs.len(), b.outputs.len(),
difficulty.clone().into_num(), difficulty.clone().into_num(),
b.header.clone().difficulty.clone().into_num(), b.header.clone().total_difficulty.clone().into_num(),
); );
// making sure we're not spending time mining a useless block // making sure we're not spending time mining a useless block

6
pool/src/pool.rs
View file

@ -912,7 +912,7 @@ mod tests {
txs.iter().collect(), txs.iter().collect(),
&keychain, &keychain,
&key_id, &key_id,
Difficulty::minimum(), Difficulty::one(),
).unwrap(); ).unwrap();
// now apply the block to ensure the chainstate is updated before we reconcile // now apply the block to ensure the chainstate is updated before we reconcile
@ -1043,7 +1043,7 @@ mod tests {
block_transactions, block_transactions,
&keychain, &keychain,
&key_id, &key_id,
Difficulty::minimum(), Difficulty::one(),
).unwrap(); ).unwrap();
chain_ref.apply_block(&block); chain_ref.apply_block(&block);
@ -1172,7 +1172,7 @@ mod tests {
tx_refs, tx_refs,
&keychain, &keychain,
&key_id, &key_id,
Difficulty::minimum() Difficulty::one(),
).unwrap(); ).unwrap();
} }

5
pow/src/lib.rs
View file

@ -166,7 +166,6 @@ mod test {
use global; use global;
use core::core::target::Difficulty; use core::core::target::Difficulty;
use core::genesis; use core::genesis;
use core::consensus::MINIMUM_DIFFICULTY;
use core::global::ChainTypes; use core::global::ChainTypes;
#[test] #[test]
@ -182,11 +181,11 @@ mod test {
pow_size( pow_size(
&mut internal_miner, &mut internal_miner,
&mut b.header, &mut b.header,
Difficulty::from_num(MINIMUM_DIFFICULTY), Difficulty::one(),
global::sizeshift() as u32, global::sizeshift() as u32,
).unwrap(); ).unwrap();
assert!(b.header.nonce != 310); assert!(b.header.nonce != 310);
assert!(b.header.pow.clone().to_difficulty() >= Difficulty::from_num(MINIMUM_DIFFICULTY)); assert!(b.header.pow.clone().to_difficulty() >= Difficulty::one());
assert!(verify_size(&b.header, global::sizeshift() as u32)); assert!(verify_size(&b.header, global::sizeshift() as u32));
} }
} }