diff --git a/.github/workflows/benchmark.yml b/.github/workflows/benchmark.yml
index b5c3e647..e646e914 100644
--- a/.github/workflows/benchmark.yml
+++ b/.github/workflows/benchmark.yml
@@ -66,6 +66,7 @@ jobs:
         env:
           TMPDIR: ${{ runner.temp }}/codspeed-valgrind-tmp
           CODSPEED_EXPERIMENTAL_FAIR_SCHED: true
+          MIMALLOC_PURGE_DELAY: "-1"
         with:
           mode: simulation
           run: cargo codspeed run