bencher: update README

crates/bencher/README.md

@@ -105,4 +105,8 @@ cd aquatic
 ./target/release-debug/aquatic_bencher udp
 # or print info on command line arguments
 ./target/release-debug/aquatic_bencher udp --help
-```
+```
+
+If you're running the load test on a virtual machine / virtual server, consider
+passing `--min-priority medium --cpu-mode subsequent-one-per-pair` for fairer
+results.