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fix: estimated hashrate calculation is incorrect (#3996)
Description --- * Created new fields in the base_node grpc api for sha3 and monero hash rates, using an independent moving average for each one * Kept the `estimated_hash_rate` field but now it corresponds to the sum of the sha3 and monero hash rates, so existing clients (i.e. web explorer) will not break * Modified the text explorer to show the estimated hash rates Motivation and Context --- The current hash rate calculation is incorrect, we want to use a separated moving average for each PoW algo independently How Has This Been Tested? --- Unit testing for the moving average hash rate calculation
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| Original file line number | Diff line number | Diff line change |
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| @@ -0,0 +1,198 @@ | ||
| // Copyright 2022. The Tari Project | ||
| // | ||
| // Redistribution and use in source and binary forms, with or without modification, are permitted provided that the | ||
| // following conditions are met: | ||
| // | ||
| // 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following | ||
| // disclaimer. | ||
| // | ||
| // 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the | ||
| // following disclaimer in the documentation and/or other materials provided with the distribution. | ||
| // | ||
| // 3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote | ||
| // products derived from this software without specific prior written permission. | ||
| // | ||
| // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, | ||
| // INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE | ||
| // DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, | ||
| // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR | ||
| // SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, | ||
| // WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE | ||
| // USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | ||
|
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||
| use std::collections::VecDeque; | ||
|
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||
| use tari_core::{ | ||
| consensus::ConsensusManager, | ||
| proof_of_work::{Difficulty, PowAlgorithm}, | ||
| }; | ||
|
|
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| /// The number of past blocks to be used on moving averages for (smooth) estimated hashrate | ||
| /// We consider a 60 minute time window reasonable, that means 12 SHA3 blocks and 18 Monero blocks | ||
| const SHA3_HASH_RATE_MOVING_AVERAGE_WINDOW: usize = 12; | ||
| const MONERO_HASH_RATE_MOVING_AVERAGE_WINDOW: usize = 18; | ||
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|
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| /// Calculates a linear weighted moving average for hash rate calculations | ||
| pub struct HashRateMovingAverage { | ||
| pow_algo: PowAlgorithm, | ||
| consensus_manager: ConsensusManager, | ||
| window_size: usize, | ||
| hash_rates: VecDeque<u64>, | ||
| average: u64, | ||
| } | ||
|
|
||
| impl HashRateMovingAverage { | ||
| pub fn new(pow_algo: PowAlgorithm, consensus_manager: ConsensusManager) -> Self { | ||
| let window_size = match pow_algo { | ||
| PowAlgorithm::Monero => MONERO_HASH_RATE_MOVING_AVERAGE_WINDOW, | ||
| PowAlgorithm::Sha3 => SHA3_HASH_RATE_MOVING_AVERAGE_WINDOW, | ||
| }; | ||
| let hash_rates = VecDeque::with_capacity(window_size); | ||
|
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||
| Self { | ||
| pow_algo, | ||
| consensus_manager, | ||
| window_size, | ||
| hash_rates, | ||
| average: 0, | ||
| } | ||
| } | ||
|
|
||
| /// Adds a new hash rate entry in the moving average and recalculates the average | ||
| pub fn add(&mut self, height: u64, difficulty: Difficulty) { | ||
| // target block time for the current block is provided by the consensus rules | ||
| let target_time = self | ||
| .consensus_manager | ||
| .consensus_constants(height) | ||
| .get_diff_target_block_interval(self.pow_algo); | ||
|
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| // remove old entries if we are at max block window | ||
| if self.is_full() { | ||
| self.hash_rates.pop_back(); | ||
| } | ||
|
|
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| // add the new hash rate to the list | ||
| let current_hash_rate = difficulty.as_u64() / target_time; | ||
| self.hash_rates.push_front(current_hash_rate); | ||
|
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||
| // after adding the hash rate we need to recalculate the average | ||
| self.average = self.calculate_average(); | ||
| } | ||
|
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| fn is_full(&self) -> bool { | ||
| self.hash_rates.len() >= self.window_size | ||
| } | ||
|
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| fn calculate_average(&self) -> u64 { | ||
| // this check is not strictly necessary as this is only called after adding an item | ||
| // but let's be on the safe side for future changes | ||
| if self.hash_rates.is_empty() { | ||
| return 0; | ||
| } | ||
|
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| let sum: u64 = self.hash_rates.iter().sum(); | ||
| let count = self.hash_rates.len() as u64; | ||
| sum / count | ||
| } | ||
|
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| pub fn average(&self) -> u64 { | ||
| self.average | ||
| } | ||
| } | ||
|
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| #[cfg(test)] | ||
| mod test { | ||
| use tari_core::{ | ||
| consensus::{ConsensusConstants, ConsensusManagerBuilder}, | ||
| proof_of_work::{Difficulty, PowAlgorithm}, | ||
| }; | ||
| use tari_p2p::Network; | ||
|
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| use super::HashRateMovingAverage; | ||
|
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| #[test] | ||
| fn window_is_empty() { | ||
| let hash_rate_ma = create_hash_rate_ma(PowAlgorithm::Sha3); | ||
| assert!(!hash_rate_ma.is_full()); | ||
| assert_eq!(hash_rate_ma.calculate_average(), 0); | ||
| assert_eq!(hash_rate_ma.average(), 0); | ||
| } | ||
|
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| #[test] | ||
| fn window_is_full() { | ||
| let mut hash_rate_ma = create_hash_rate_ma(PowAlgorithm::Sha3); | ||
| let window_size = hash_rate_ma.window_size; | ||
|
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| // we check that the window is not full when we insert less items than the window size | ||
| for _ in 0..window_size - 1 { | ||
| hash_rate_ma.add(0, Difficulty::from(0)); | ||
| assert!(!hash_rate_ma.is_full()); | ||
| } | ||
|
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| // from this point onwards, the window should be always full | ||
| for _ in 0..10 { | ||
| hash_rate_ma.add(0, Difficulty::from(0)); | ||
| assert!(hash_rate_ma.is_full()); | ||
| } | ||
| } | ||
|
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| // Checks that the moving average hash rate at every block is correct | ||
| // We use larger sample data than the SHA window size (12 periods) to check bounds | ||
| // We assumed a constant target block time of 300 secs (the SHA3 target time for Dibbler) | ||
| // These expected hash rate values where calculated in a spreadsheet | ||
| #[test] | ||
| fn correct_moving_average_calculation() { | ||
| let mut hash_rate_ma = create_hash_rate_ma(PowAlgorithm::Sha3); | ||
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| assert_hash_rate(&mut hash_rate_ma, 0, 100_000, 333); | ||
| assert_hash_rate(&mut hash_rate_ma, 1, 120_100, 366); | ||
| assert_hash_rate(&mut hash_rate_ma, 2, 110_090, 366); | ||
| assert_hash_rate(&mut hash_rate_ma, 3, 121_090, 375); | ||
| assert_hash_rate(&mut hash_rate_ma, 4, 150_000, 400); | ||
| assert_hash_rate(&mut hash_rate_ma, 5, 155_000, 419); | ||
| assert_hash_rate(&mut hash_rate_ma, 6, 159_999, 435); | ||
| assert_hash_rate(&mut hash_rate_ma, 7, 160_010, 448); | ||
| assert_hash_rate(&mut hash_rate_ma, 8, 159_990, 457); | ||
| assert_hash_rate(&mut hash_rate_ma, 9, 140_000, 458); | ||
| assert_hash_rate(&mut hash_rate_ma, 10, 137_230, 458); | ||
| assert_hash_rate(&mut hash_rate_ma, 11, 130_000, 456); | ||
| assert_hash_rate(&mut hash_rate_ma, 12, 120_000, 461); | ||
| assert_hash_rate(&mut hash_rate_ma, 13, 140_000, 467); | ||
| } | ||
|
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| // Our moving average windows are very small (12 and 15 depending on PoW algorithm) | ||
| // So we will never get an overflow when we do the sums for the average calculation (we divide by target time) | ||
| // Anyways, just in case we go with huge windows in the future, this test should fail with a panic due to overflow | ||
| #[test] | ||
| fn should_not_overflow() { | ||
| let mut sha3_hash_rate_ma = create_hash_rate_ma(PowAlgorithm::Sha3); | ||
| let mut monero_hash_rate_ma = create_hash_rate_ma(PowAlgorithm::Monero); | ||
| try_to_overflow(&mut sha3_hash_rate_ma); | ||
| try_to_overflow(&mut monero_hash_rate_ma); | ||
| } | ||
|
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| fn try_to_overflow(hash_rate_ma: &mut HashRateMovingAverage) { | ||
| let window_size = hash_rate_ma.window_size; | ||
|
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| for _ in 0..window_size { | ||
| hash_rate_ma.add(0, Difficulty::from(u64::MAX)); | ||
| } | ||
| } | ||
|
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| fn create_hash_rate_ma(pow_algo: PowAlgorithm) -> HashRateMovingAverage { | ||
| let consensus_manager = ConsensusManagerBuilder::new(Network::Dibbler) | ||
| .add_consensus_constants(ConsensusConstants::dibbler()[0].clone()) | ||
| .build(); | ||
| HashRateMovingAverage::new(pow_algo, consensus_manager) | ||
| } | ||
|
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| fn assert_hash_rate( | ||
| moving_average: &mut HashRateMovingAverage, | ||
| height: u64, | ||
| difficulty: u64, | ||
| expected_hash_rate: u64, | ||
| ) { | ||
| moving_average.add(height, Difficulty::from(difficulty)); | ||
| assert_eq!(moving_average.average(), expected_hash_rate); | ||
| } | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
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@@ -22,4 +22,5 @@ | |
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| pub mod base_node_grpc_server; | ||
| pub mod blocks; | ||
| pub mod hash_rate; | ||
| pub mod helpers; | ||
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