make test thread number configurable

crates/cast/bin/cmd/create2.rs

@@ -169,7 +169,7 @@ impl Create2Args {
 
         let regex = RegexSetBuilder::new(regexs).case_insensitive(!case_sensitive).build()?;
 
-        let n_threads = global.jobs().unwrap_or(1);
+        let n_threads = global.jobs(true).unwrap_or(1);
 
         let mut salt = B256::ZERO;
         let remaining = if let Some(caller_address) = caller {

crates/cli/src/opts/global.rs

@@ -70,15 +70,15 @@ impl GlobalOpts {
 
     /// Spawn a new global thread pool.
     pub fn try_spawn(self, jobs: Option<usize>) -> Result<(), rayon::ThreadPoolBuildError> {
-        if let Some(jobs) = jobs.or_else(|| self.jobs()) {
+        if let Some(jobs) = jobs.or_else(|| self.jobs(false)) {
+            trace!(target: "forge::cli", "starting global thread pool with up to {} threads", jobs);
+
             // Attempt to spawn the global thread pool with the specified number of threads.
             // If it is already initialized simply return.
             if ThreadPoolBuilder::new().num_threads(jobs).build_global().is_err() {
-                return Ok(());
+                warn!(target: "forge::cli", "global thread pool already initialized");
             }
 
-            trace!(target: "forge::cli", "starting global thread pool with up to {} threads", jobs);
-
             Ok(())
         } else {
             // If `--jobs` is not provided, do not spawn the global thread pool.
@@ -90,14 +90,18 @@ impl GlobalOpts {
     ///
     /// Try to use the number of threads specified by `--jobs` if provided, otherwise use the number
     /// of logical CPUs.
-    pub fn jobs(&self) -> Option<usize> {
-        self.jobs.map(|jobs| {
+    pub fn jobs(&self, default: bool) -> Option<usize> {
+        if let Some(jobs) = self.jobs {
             if jobs == 0 {
-                current_num_threads()
-            } else {
-                jobs.min(current_num_threads())
+                return Some(current_num_threads());
             }
-        })
+
+            Some(jobs.min(current_num_threads()))
+        } else if default {
+            return Some(current_num_threads());
+        } else {
+            return None;
+        }
     }
 
     /// Create a new shell instance.

crates/forge/bin/cmd/test/mod.rs

@@ -38,7 +38,6 @@ use foundry_config::{
 };
 use foundry_debugger::Debugger;
 use foundry_evm::traces::identifier::TraceIdentifiers;
-use rayon::current_num_threads;
 use regex::Regex;
 use std::{
     collections::{BTreeMap, BTreeSet},
@@ -895,7 +894,7 @@ impl Provider for TestArgs {
             dict.insert("show_progress".to_string(), true.into());
         }
 
-        if let Some(threads) = self.global.jobs().or(Some(current_num_threads())) {
+        if let Some(threads) = self.global.jobs(true) {
             dict.insert("threads".to_string(), threads.into());
         }
 

crates/forge/src/multi_runner.rs

@@ -23,7 +23,7 @@ use foundry_evm::{
     traces::{InternalTraceMode, TraceMode},
 };
 use foundry_linking::{LinkOutput, Linker};
-use rayon::prelude::*;
+use rayon::{current_num_threads, prelude::*};
 use revm::primitives::SpecId;
 use std::{
     borrow::Borrow,
@@ -185,7 +185,10 @@ impl MultiContractRunner {
         );
 
         if show_progress {
-            let tests_progress = TestsProgress::new(contracts.len(), rayon::current_num_threads());
+            let tests_progress = TestsProgress::new(
+                contracts.len(),
+                self.config.threads.unwrap_or(current_num_threads()),
+            );
             // Collect test suite results to stream at the end of test run.
             let results: Vec<(String, SuiteResult)> = contracts
                 .par_iter()