Top Tweets for #xrust

We love tech and we go always the next level to optimise all the aspects of any component. Today, as requested by community, let's talk about our Virtual Machine (soon to have a better name than WASM). Someone said that "MvX hasn't made any significantly big changes ... their VM is WASM". This is far from truth. The #MultiversX VM is far from being simple and it has multiple layers, tens of features, all optimised out till the last bit. Technically speaking, when we talk about the Execution Environment we have at leat 3 different layers, and if we go top to bottom here they are: 1. SmartContract Processor and BlockchainHooks: First, it prepares the VMInput data from the transaction, takes out the fee from the balance, executes all $ESDT transfers and then it calls the SmartContractExecutionHandler chosen from the smart contract address. Actually we have 2 running VMs on-chain, one with contract written in GO and executed in GO (systemVM) and another one for WASM contracts. At the end of the execution, the SCProcessor makes a big set of sanity checks, computes the developer rewards, creates the needed cross shard messages, actually writes all the modifications which came as a VMOutput structure into the trie. Innovations/features here: asynchronous calls V1 and V2, cross shard transaction processing and message preparations, all the $ESDT token system, actually guardian verifications, developer rewards. Handling all the revert in case of errors. 2. The virtual machine: Is already at its 5th version/iteration. One of the first big implementations and improvements to be done here was writing and reading from the internal VM cache at the time of the execution, not writing intermediary steps to the blockchain state (this is still done in legacy L1s). There is no need to write intermediary changes, only the last one, and only if the execution is a success. STATELESSNESS. Here we implemented the Ahead of Time compilation module, which reduced the contract preparation time by 80%. Almost a 5x improvement in execution speed. Meaning, any contract is compiled and kept in a serialized format on storage and cache, no need to do that at every execution. A changed serialization format have sped up the preparation phase by 60%. Next in line was WarmInstances. Instead of deserializing and executing every time a contract, we just keep the WASM executable object as a warm instance and only cleaning up the memory of these objects. Even faster execution, at least a 2x improvement from the AoT version. This is the fastest way to execute in one thread complexe Smart Contracts. This was for speed, but we never stopped there. Enshrining $ESDT transfers inside the Virtual Machine was a must in order to make it easier to develop complex financial apps. All modes of execution (sync/async) complemented with transfers handled directly by the VM. This eliminated all the re-entrancy issues. And we could do more, implementing a set of common goods, libraries directly inside the VM as OPCODE: crypto (schnorr, BLSsingle, BLSMulti), bigInt/bigFloat/elliptic curve math, managed maps, managed objects, strings (it is called sentient storage on EVM - not yet implemented), secure randomness, asyncCalls V1 and V2. Lastly the new backTransfer feature, which makes creating any SC on top of a DEX a simple few liners as all the transfers sent by the child contract to the parent is cached by the VM and given out to the parent. No need for interpretations of SC output, deserialization or complex code to understand the child SCs output. <payments, results> = ExecuteOnDest(child). This makes DeFi legoblocks easier to create. 3. WASM engine: using Wasmer implementation for a compilation based WASM engine, running the SinglePass code. Improved communication with the blockchain, improved the ahead of time compilation module inside Wasmer, actually created the Warm Instance module and cleanup inside the Wasmer codebase. Extra security checks, disallowed a set of WASM OPCODES, interfacing of WASM objects directly to GO code. Integrated the Gas Module deep inside the Wasmer processing library. Now, this is what we call Virtual Machine - or one could say Execution Environment. It is complex, built for speed and security of the users and developers. Every bit of optimisation matters. And not all features were described in this post. This was and is unprecedented in the #blockchain world. No VM has this many features built in. Next things here: - asynchronous calls V3 - multilayer multi async calls - enshrined zero knowledge verifier libraries as OPCODES - more crypto libraries - seckpr1 - parallelisation of execution - prefetching data before execution - ahead of time storage preparation - linear type storage and managed objects. And let's not forget: