Cap number of worker threads

.gitlab-ci.yml

@@ -234,7 +234,9 @@ run-sim:
     # Limit to 20 threads - Shadow should assign them all to the same Numa node, leaving othe other node idle,
     # but ensuring we don't have cross-node memory access.
     - PARALLELISM=20
-    - tornettools simulate -s $CI_PROJECT_DIR/jobs/opt/shadow/bin/shadow -a "--use-cpu-pinning=true --interpose-method=preload -p $PARALLELISM --template-directory=shadow.data.template" $CI_PROJECT_DIR/jobs/tornet
+    # We run into system limits on # of threads if we do the default of creating one per managed process.
+    - WORKER_THREADS=200
+    - tornettools simulate -s $CI_PROJECT_DIR/jobs/opt/shadow/bin/shadow -a "--use-cpu-pinning=true --interpose-method=preload -p $PARALLELISM --worker-threads=$WORKER_THREADS --template-directory=shadow.data.template" $CI_PROJECT_DIR/jobs/tornet
 
     # Parse simulation results.
     # The raw results are too large to save as an artifact.