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exchange-core

Exchange-core is an open source market exchange core based on LMAX Disruptor, Eclipse Collections (ex. Goldman Sachs GS Collections), Real Logic Agrona, OpenHFT Chronicle-Wire, LZ4 Java, and Adaptive Radix Trees.

Exchange-core includes:

• orders matching engine
• risk control and accounting module
• disk journaling and snapshots module
• trading, admin and reports API

Designed for high scalability and pauseless 24/7 operation under high-load conditions and providing low-latency responses:

• 3M users having 10M accounts in total
• 100K order books (symbols) having 4M pending orders in total
• less than 1ms worst wire-to-wire target latency for 1M+ operations per second throughput
• 150ns per matching for large market orders

Single order book configuration is capable to process 5M operations per second on 10-years old hardware (Intel® Xeon® X5690) with moderate latency degradation:

Benchmark configuration:

• Single symbol order book.
• 3,000,000 inbound messages are distributed as follows: 9% GTC orders, 3% IOC orders, 6% cancel commands, 82% move commands. About 6% of all messages are triggering one or more trades.
• 1,000 active user accounts.
• In average ~1,000 limit orders are active, placed in ~750 different price slots.
• Latency results are only for risk processing and orders matching. Other stuff like network interface latency, IPC, journaling is not included.
• Test data is not bursty, meaning constant interval between commands (0.2~8µs depending on target throughput).
• BBO prices are not changing significantly throughout the test. No avalanche orders.
• No coordinated omission effect for latency benchmark. Any processing delay affects measurements for next following messages.
• GC is triggered prior/after running every benchmark cycle (3,000,000 messages).
• RHEL 7.5, network-latency tuned-adm profile, dual X5690 6 cores 3.47GHz, one socket isolated and tickless, spectre/meltdown protection disabled.
• Java version 8u192, newer Java 8 versions can have a performance bug

Features

• HFT optimized. Priority is a limit-order-move operation mean latency (currently ~0.5µs). Cancel operation takes ~0.7µs, placing new order ~1.0µs;
• In-memory working state for accounting data and order books.
• Event-sourcing - disk journaling and journal replay support, state snapshots (serialization) and restore operations, LZ4 compression.
• Lock-free and contention-free orders matching and risk control algorithms.
• No floating-point arithmetic, no loss of significance is possible.
• Matching engine and risk control operations are atomic and deterministic.
• Pipelined multi-core processing (based on LMAX Disruptor): each CPU core is responsible for certain processing stage, user accounts shard, or symbol order books shard.
• Two different risk processing modes (specified per symbol): direct-exchange and margin-trade.
• Maker/taker fees (defined in quote currency units).
• Two order books implementations: simple implementation ("Naive") and performance implementation ("Direct").
• Order types: Immediate-or-Cancel (IOC), Good-till-Cancel (GTC), Fill-or-Kill Budget (FOK-B)
• Testing - unit-tests, integration tests, stress tests, integrity/consistency tests.
• Low GC pressure, objects pooling, single ring-buffer.
• Threads affinity (requires JNA).
• User suspend/resume operation (reduces memory consumption).
• Core reports API (user balances, open interest).

Installation

1. Install library into your Maven's local repository by running mvn install
2. Add the following Maven dependency to your project's pom.xml:

<dependency>
    <groupId>exchange.core2</groupId>
    <artifactId>exchange-core</artifactId>
    <version>0.5.3</version>
</dependency>

Alternatively, you can clone this repository and run the example test.

Usage examples

Create and start empty exchange core:

// simple async events handler
SimpleEventsProcessor eventsProcessor = new SimpleEventsProcessor(new IEventsHandler() {
    @Override
    public void tradeEvent(TradeEvent tradeEvent) {
        System.out.println("Trade event: " + tradeEvent);
    }

    @Override
    public void reduceEvent(ReduceEvent reduceEvent) {
        System.out.println("Reduce event: " + reduceEvent);
    }

    @Override
    public void rejectEvent(RejectEvent rejectEvent) {
        System.out.println("Reject event: " + rejectEvent);
    }

    @Override
    public void commandResult(ApiCommandResult commandResult) {
        System.out.println("Command result: " + commandResult);
    }

    @Override
    public void orderBook(OrderBook orderBook) {
        System.out.println("OrderBook event: " + orderBook);
    }
});

// default exchange configuration
ExchangeConfiguration conf = ExchangeConfiguration.defaultBuilder().build();

// no serialization
Supplier<ISerializationProcessor> serializationProcessorFactory = () -> DummySerializationProcessor.INSTANCE;

// build exchange core
ExchangeCore exchangeCore = ExchangeCore.builder()
        .resultsConsumer(eventsProcessor)
        .serializationProcessorFactory(serializationProcessorFactory)
        .exchangeConfiguration(conf)
        .build();

// start up disruptor threads
exchangeCore.startup();

// get exchange API for publishing commands
ExchangeApi api = exchangeCore.getApi();

Create new symbol:

// currency code constants
final int currencyCodeXbt = 11;
final int currencyCodeLtc = 15;

// symbol constants
final int symbolXbtLtc = 241;

// create symbol specification and publish it
CoreSymbolSpecification symbolSpecXbtLtc = CoreSymbolSpecification.builder()
        .symbolId(symbolXbtLtc)         // symbol id
        .type(SymbolType.CURRENCY_EXCHANGE_PAIR)
        .baseCurrency(currencyCodeXbt)    // base = satoshi (1E-8)
        .quoteCurrency(currencyCodeLtc)   // quote = litoshi (1E-8)
        .baseScaleK(1_000_000L) // 1 lot = 1M satoshi (0.01 BTC)
        .quoteScaleK(10_000L)   // 1 price step = 10K litoshi
        .takerFee(1900L)        // taker fee 1900 litoshi per 1 lot
        .makerFee(700L)         // maker fee 700 litoshi per 1 lot
        .build();

future = api.submitBinaryDataAsync(new BatchAddSymbolsCommand(symbolSpecXbtLtc));

Create new users:

// create user uid=301
future = api.submitCommandAsync(ApiAddUser.builder()
        .uid(301L)
        .build());

// create user uid=302
future = api.submitCommandAsync(ApiAddUser.builder()
        .uid(302L)
        .build());

Perform deposits:

// first user deposits 20 LTC
future = api.submitCommandAsync(ApiAdjustUserBalance.builder()
        .uid(301L)
        .currency(currencyCodeLtc)
        .amount(2_000_000_000L)
        .transactionId(1L)
        .build());

// second user deposits 0.10 BTC
future = api.submitCommandAsync(ApiAdjustUserBalance.builder()
        .uid(302L)
        .currency(currencyCodeXbt)
        .amount(10_000_000L)
        .transactionId(2L)
        .build());

Place orders:

// first user places Good-till-Cancel Bid order
// he assumes BTCLTC exchange rate 154 LTC for 1 BTC
// bid price for 1 lot (0.01BTC) is 1.54 LTC => 1_5400_0000 litoshi => 10K * 15_400 (in price steps)
future = api.submitCommandAsync(ApiPlaceOrder.builder()
        .uid(301L)
        .orderId(5001L)
        .price(15_400L)
        .reservePrice(15_600L) // can move bid order up to the 1.56 LTC, without replacing it
        .size(12L) // order size is 12 lots
        .action(OrderAction.BID)
        .orderType(OrderType.GTC) // Good-till-Cancel
        .symbol(symbolXbtLtc)
        .build());

// second user places Immediate-or-Cancel Ask (Sell) order
// he assumes wost rate to sell 152.5 LTC for 1 BTC
future = api.submitCommandAsync(ApiPlaceOrder.builder()
        .uid(302L)
        .orderId(5002L)
        .price(15_250L)
        .size(10L) // order size is 10 lots
        .action(OrderAction.ASK)
        .orderType(OrderType.IOC) // Immediate-or-Cancel
        .symbol(symbolXbtLtc)
        .build());

Request order book:

future = api.requestOrderBookAsync(symbolXbtLtc, 10);

GtC orders manipulations:

// first user moves remaining order to price 1.53 LTC
future = api.submitCommandAsync(ApiMoveOrder.builder()
        .uid(301L)
        .orderId(5001L)
        .newPrice(15_300L)
        .symbol(symbolXbtLtc)
        .build());
        
// first user cancel remaining order
future = api.submitCommandAsync(ApiCancelOrder.builder()
        .uid(301L)
        .orderId(5001L)
        .symbol(symbolXbtLtc)
        .build());

Check user balance and GtC orders:

Future<SingleUserReportResult> report = api.processReport(new SingleUserReportQuery(301), 0);

Check system balance:

// check fees collected
Future<TotalCurrencyBalanceReportResult> totalsReport = api.processReport(new TotalCurrencyBalanceReportQuery(), 0);
System.out.println("LTC fees collected: " + totalsReport.get().getFees().get(currencyCodeLtc));

Testing

• latency test: mvn -Dtest=PerfLatency#testLatencyMargin test
• throughput test: mvn -Dtest=PerfThroughput#testThroughputMargin test
• hiccups test: mvn -Dtest=PerfHiccups#testHiccups test
• serialization test: mvn -Dtest=PerfPersistence#testPersistenceMargin test

TODOs

• market data feeds (full order log, L2 market data, BBO, trades)
• clearing and settlement
• reporting
• clustering
• FIX and REST API gateways
• cryptocurrency payment gateway
• more tests and benchmarks
• NUMA-aware and CPU layout custom configuration

Contributing

Exchange-core is an open-source project and contributions are welcome!

Support

• Discussion group in Telegram (t.me/exchangecoretalks)
• News channel in Telegram (t.me/exchangecore)