Refactor evm Instruction to be a c-like enum #8914

sorpaas · 2018-06-18T09:00:21Z

This allows some more type checking for the type, and also allows to put functions in a more Rust-y way.

A small macro is used to implement from_u8 using match. A small part of this marco is from enum_derive crate. But that crate defines other functions (like from_u64, etc) which we don't use.
INSTRUCTIONS table is made private, and it's accessed from Instruction::info(&self).
Put exec_stack_instruction to exec_instruction. This allows Rust to type check match arms, and refuse to compile if new opcode is added, but its execution logic is not defined.

sorpaas · 2018-06-18T09:04:19Z

ethcore/evm/src/instructions.rs

-		arr[REVERT as usize] =			InstructionInfo::new("REVERT",			2, 0, GasPriceTier::Zero);
+	static ref INSTRUCTIONS: [Option<InstructionInfo>; 0x100] = {
+		let mut arr = [None; 0x100];
+		arr[STOP as usize] =			Some(InstructionInfo::new("STOP",			0, 0, GasPriceTier::Zero));


This tab formatting displays correctly on my Emacs, but looks like it doesn't work on Github interface.
I'm thinking about maybe it's better to just use a single space as separator -- we don't gain much readability by using multiple tabs.

tomusdrw

Looks good, although I would insists on having some representative benchmarks for the baseline before merging any EVM changes.
The earlier we catch performance regressions or improvements the better.

tomusdrw · 2018-06-19T13:32:56Z

ethcore/evm/src/instructions.rs

+			#[doc = "Convert from u8 to the given enum"]
+			pub fn from_u8(value: u8) -> Option<Self> {
+				match value {
+					$( $discriminator => Some($variant) ),+,


Are we sure it's equally performant to borrowing from the static array?

Instruction is repr(u8), and here we use match to convert a raw u8 to an repr(u8). We're still borrowing instruction info from the INSTRUCTIONS static array, in info(&self).

Anyway I'll try a benchmark on the new code.

tomusdrw · 2018-06-19T13:37:35Z

ethcore/evm/src/interpreter/shared_cache.rs

+			if let Some(instruction) = instruction {
+				if instruction == instructions::JUMPDEST {
+					jump_dests.insert(position);
+				} else if instruction.is_push() {


Maybe change that to if let Some(xx) = instructions.push_bytes() { ?

tomusdrw · 2018-06-19T13:40:17Z

ethcore/evm/src/interpreter/mod.rs


 		while reader.position < code.len() {
-			let instruction = code[reader.position];
+			let opcode = code[reader.position];
+			let instruction = Instruction::from_u8(opcode);


Might be worth mapping the code to Instructions during the first phase along with jumpdestination analysis.

The current issue is that we only calculate valid jump destinations upon first JUMP instruction, so on L129 that info may not be available.

I'll try and see (probably in a future PR) whether incrementally calculating jumpdests along with the exec loop would be possible, or another idea is to store jumpdest result to the db -- that info is static and never changes for a particular code array.

sorpaas · 2018-06-20T06:36:15Z

Here's the result got from evmbin/bench.sh:

This PR:

Output: 0x606060405200
Gas used: 29fb170
Time: 0.511926861s
^^^^ usize
Output: 0x606060405200
Gas used: 29fb170
Time: 0.519975655s
^^^^ U256
Output: 0x606060405200
Gas used: 8865053
Time: 1.749029145s
^^^^ usize
Output: 0x606060405200
Gas used: 8865053
Time: 1.787731034s
^^^^ U256

Master Branch:

Output: 0x606060405200
Gas used: 29fb170
Time: 0.573969108s
^^^^ usize
Output: 0x606060405200
Gas used: 29fb170
Time: 0.562567334s
^^^^ U256
Output: 0x606060405200
Gas used: 8865053
Time: 2.61541081s
^^^^ usize
Output: 0x606060405200
Gas used: 8865053
Time: 2.23390354s
^^^^ U256

Looks like somehow the conversion to enum makes it run just slightly faster..

Don't know whether this is representative enough. We can also try some benchmarks using some of the jsontests.

sorpaas · 2018-06-25T07:03:22Z

I got some benchmarks using #8944. Currently, running the comparison requires manually checking out two branches so it's not hassle-free. Another issue is that many tests only run for a really short time, and I cannot find a reliable way to make some of the results really comparable.

Below is a tuple of tests that run faster in this PR, 0-10% slower, 10-20% slower, 20-30% slower, 30-40% slower, 40-50% slower or 50%+ slower:

(256, 150, 66, 23, 43, 62, 73)

This tuple varies a lot each time I run the tests and gather the csv.

In particular, the performance tests in vm folder might be representive:

{'ackermann31-INT': 0.9897959183673469,
 'ackermann32-INT': 0.9167478091528725,
 'ackermann33-INT': 0.9596136962247586,
 'fibonacci10-INT': 1.0860832137733143,
 'fibonacci16-INT': 0.9300284017557449,
 'loop-add-10M-INT': 0.9226587206771758,
 'loop-divadd-10M-INT': 0.9229079794970425,
 'loop-divadd-unr100-10M-INT': 0.8998631955175739,
 'loop-exp-16b-100k-INT': 1.0188090390141178,
 'loop-exp-1b-1M-INT': 0.9923591588497622,
 'loop-exp-2b-100k-INT': 0.9466506030511994,
 'loop-exp-32b-100k-INT': 1.0991487959483188,
 'loop-exp-4b-100k-INT': 1.12556930650952,
 'loop-exp-8b-100k-INT': 1.1088218849334053,
 'loop-exp-nop-1M-INT': 0.8219694300785856,
 'loop-mul-INT': 0.8684106995830124,
 'loop-mulmod-2M-INT': 0.9754786210274101,
 'manyFunctions100-INT': 0.8409570724841661}

The value is timing in this PR / timing on master.

Those results are gathered by running evm_jsontests_bench.sh and then using a half-finished Jupyter notebook. I don't think that notebook is publishable, but I'll put it up as a gist once I cleared it up.

tomusdrw · 2018-06-25T08:40:27Z

@sorpaas Great, that's good enough for me. I think the performance tests and perhaps evmbin/benches.rs should be a good indicator, so I'd focus on running those.
Maybe we add some more tests to evmbin/benches (separate PR) and use only this in future? Will simplify comparing the changes in the future.

jimpo

Nice refactor! (and speedup)

jimpo · 2018-06-26T02:06:48Z

ethcore/evm/src/instructions.rs

-		GasPriceTier::Invalid
+impl GasPriceTier {
+	/// Returns the index in schedule for specific `GasPriceTier`
+	pub fn idx(&self) -> usize {


Could these also be numbered with a C-style enum instead of having the separate mapping method?

That "c-style enum" is actually just GasPriceTier. :)

We still need this idx function. It's used in schedule, where we dispatch based on the index to know about the default gas.

Ah, didn't realize the values were assigned implicitly. In that case, seems like this method could just be implemented as *self as usize instead of the match, or inlined.

I'm not really sure about that -- the performance is mostly same, but I'm a little bit concerned about clarity.

Unlike Instruction, We don't have enum-to-number natural corresponding for GasPriceTier. I tried adding the index to enum and make GasPriceTier a c-like enum. The issue, however, is that there're other number corresponding for GasPriceTier (like default gas cost). And the result might be a little bit confusing.

jimpo · 2018-06-26T02:07:44Z

ethcore/evm/src/interpreter/gasometer.rs

-			instructions::LOG0...instructions::LOG4 => {
-				let no_of_topics = instructions::get_log_topics(instruction);
+			instructions::LOG0 | instructions::LOG1 | instructions::LOG2 | instructions::LOG3 | instructions::LOG4 => {
+				let no_of_topics = instruction.log_topics().expect("log_topcis always return some for LOG* instructions; qed");


typo: s/topcis/topics/

jimpo · 2018-06-26T03:50:27Z

ethcore/evm/src/interpreter/mod.rs

 			self.verify_instruction(ext, instruction, info, &stack)?;

 			// Calculate gas cost
 			let requirements = gasometer.requirements(ext, instruction, info, &stack, self.mem.size())?;
 			if do_trace {
-				ext.trace_prepare_execute(reader.position - 1, instruction, requirements.gas_cost.as_u256());
+				ext.trace_prepare_execute(reader.position - 1, instruction as u8, requirements.gas_cost.as_u256());


nit: Could use opcode instead of instruction as u8.

jimpo · 2018-06-26T03:50:32Z

ethcore/evm/src/interpreter/mod.rs

-		if info.tier == instructions::GasPriceTier::Invalid {
-			return Err(vm::Error::BadInstruction {
-				instruction: instruction
+				instruction: instruction as u8


nit: Could use opcode instead of instruction as u8.

We don't have opcode variable in verify_instruction. Because instruction as u8 is basically a noop, I think this would be okay?

5chdn · 2018-06-26T16:24:24Z

Please rebase on latest master to fix CI.

…rpaas/evm-instructions

ascjones

Nice!

…rp_sync_on_light_client * 'master' of https://github.com/paritytech/parity: Refactor evm Instruction to be a c-like enum (openethereum#8914)

* master: Refactor evm Instruction to be a c-like enum (#8914) Fix deadlock in blockchain. (#8977) snap: downgrade rust to revision 1.26.2, ref snapcraft/+bug/1778530 (#8984) Use local parity-dapps-glue instead of crate published at crates.io (#8983) parity: omit redundant last imported block number in light sync informant (#8962) Disable hardware-wallets on platforms that don't support `libusb` (#8464) Bump error-chain and quick_error versions (#8972)

sorpaas added 5 commits June 18, 2018 14:43

Add a basic instruction c-like enum

d26270d

Fix all compiling errors

319455d

Fix tests

2bc32c5

Access instruction info as a Instruction impl

ea78118

Use macro to avoid duplication in from_u8

7771696

sorpaas added A0-pleasereview 🤓 Pull request needs code review. F6-refactor 📚 Code needs refactoring. labels Jun 18, 2018

sorpaas added this to the 1.12 milestone Jun 18, 2018

sorpaas commented Jun 18, 2018

View reviewed changes

Use single space instead of multiple tabs to avoid formatting issue

75cb145

sorpaas added the M4-core ⛓ Core client code / Rust. label Jun 18, 2018

sorpaas added 2 commits June 18, 2018 17:37

Fix evmbin compile

7067c7a

typo: indentation

c6daaf7

debris requested a review from tomusdrw June 19, 2018 13:10

tomusdrw reviewed Jun 19, 2018

View reviewed changes

Use if let to remove an expect

a96e354

sorpaas mentioned this pull request Jun 21, 2018

EVM benchmark utilities #8944

Merged

tomusdrw approved these changes Jun 25, 2018

View reviewed changes

jimpo approved these changes Jun 26, 2018

View reviewed changes

Address grumbles

7e036b1

5chdn added A8-looksgood 🦄 Pull request is reviewed well. and removed A0-pleasereview 🤓 Pull request needs code review. labels Jun 26, 2018

Merge branch 'master' of https://github.com/paritytech/parity into so…

3f1a9fb

…rpaas/evm-instructions

ascjones approved these changes Jun 27, 2018

View reviewed changes

5chdn merged commit 0bed597 into master Jun 27, 2018

5chdn deleted the sorpaas/evm-instructions branch June 27, 2018 11:33

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Refactor evm Instruction to be a c-like enum #8914

Refactor evm Instruction to be a c-like enum #8914

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Refactor evm Instruction to be a c-like enum #8914

Refactor evm Instruction to be a c-like enum #8914

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