From 1405d07bfb7ddb11603ee76074e0a534592f72f7 Mon Sep 17 00:00:00 2001
From: not-matthias <matthias@codspeed.io>
Date: Thu, 20 Aug 2026 15:12:28 +0200
Subject: [PATCH] fix(valgrind): tie --separate-threads to subprocess tracking

Thread separation was keyed on --cycle-estimation, which controls how
event costs are computed, not how they are partitioned. Per-thread dumps
only matter when instrumentation is inherited across a traced exec, so
key the option on the subprocess-tracking flag instead and set it
explicitly in both branches.
---
 src/executor/valgrind/measure.rs | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/src/executor/valgrind/measure.rs b/src/executor/valgrind/measure.rs
index 54bddf1a..62807b92 100644
--- a/src/executor/valgrind/measure.rs
+++ b/src/executor/valgrind/measure.rs
@@ -33,19 +33,18 @@ fn get_valgrind_args(tool: &SimulationTool, config: &ExecutorConfig) -> Vec<Stri
     .map(|x| x.to_string())
     .collect();
 
-    args.push(if config.simulation_track_subprocess {
-        "--instr-atstart=inherit".to_string()
+    if config.simulation_track_subprocess {
+        args.push("--instr-atstart=inherit".to_string());
+        args.push("--separate-threads=yes".to_string());
     } else {
-        "--instr-atstart=no".to_string()
-    });
+        args.push("--instr-atstart=no".to_string());
+        args.push("--separate-threads=no".to_string());
+    }
 
     match tool {
         SimulationTool::Callgrind => {
             if config.cycle_estimation {
                 args.push("--cycle-estimation=yes".to_string());
-                args.push("--separate-threads=yes".to_string());
-            } else {
-                args.push("--separate-threads=no".to_string());
             }
 
             args.push("--tool=callgrind".to_string());