starknet_in_rust performance

[kkovaacs]

For some reason our re_execute tool is significantly slower with starknet_in_rust than it is with blockifier.
With blockifier:

target/release/examples/re_execute ./mainnet.sqlite 82000 82100  225,50s user 7,90s system 2122% cpu 10,998 total

That is, re-executing blocks from 82000 to 82100 takes ~11s.

With starknet_in_rust:

target/release/examples/re_execute ./mainnet.sqlite 82000 8210  1765,70s user 60,95s system 2208% cpu 1:22,71 total

Having had a quick look at the flamegraph it seems ContractClass cloning/dropping is pretty much dominating:

[kkovaacs]

Looks like adding a trivial change that adds an Arc around program_json in ContractClass leads to a very substantial improvement:

target/release/examples/re_execute ./mainnet.sqlite 82000 82100  325,04s user 12,65s system 2198% cpu 15,363 total

[kkovaacs]

The diff for the experiment above:

diff --git a/src/services/api/contract_classes/deprecated_contract_class.rs b/src/services/api/contract_classes/deprecated_contract_class.rs
index 0ac5f80..b1a0b96 100644
--- a/src/services/api/contract_classes/deprecated_contract_class.rs
+++ b/src/services/api/contract_classes/deprecated_contract_class.rs
@@ -12,6 +12,7 @@ use starknet_api::deprecated_contract_class::{ContractClassAbiEntry, EntryPoint}
 use std::collections::HashMap;
 use std::io::{BufReader, Read};
 use std::path::{Path, PathBuf};
+use std::sync::Arc;
 
 pub type AbiType = Vec<ContractClassAbiEntry>;
 
@@ -75,7 +76,7 @@ pub struct ContractClass {
     #[getset(get = "pub")]
     pub(crate) program: Program,
     #[getset(get = "pub")]
-    pub(crate) program_json: serde_json::Value,
+    pub(crate) program_json: Arc<serde_json::Value>,
     #[getset(get = "pub")]
     pub(crate) entry_points_by_type: HashMap<EntryPointType, Vec<ContractEntryPoint>>,
     #[getset(get = "pub")]
@@ -98,7 +99,7 @@ impl ContractClass {
         }
 
         Ok(ContractClass {
-            program_json,
+            program_json: program_json.into(),
             program,
             entry_points_by_type,
             abi,

[Oppen]

I'd suggest splitting structs so we can include anything that's constant in the same Arc. We do that for Program with the SharedProgramData structure.

[juanbono]

Thanks for such a detailed issue @kkovaacs ! We'll apply that change. Also we are going to start improving the performance of starknet_in_rust soon. Let's talk about your idea @Oppen, I think there is a lot of room for improvement and we can apply the same ideas from cairo-vm (as the one you mentioned) for that.