Seems like this can be useful on its own, although I wonder if fixing -- together with --bench is not better. Maybe (although its not perfect probably):

diff --git a/runtests.py b/runtests.py
index e470f8a9d..2d9a0f39d 100755
--- a/runtests.py
+++ b/runtests.py
@@ -220,7 +220,14 @@ def main(argv):
 
     if args.bench:
         # Run ASV
-        items = extra_argv
+        if "--" in extra_argv:
+            split = extra_argv.index("--")
+            items = extra_argv[:split]
+            extra_argv = extra_argv[split+1:]
+        else:
+            items = extra_argv
+            extra_argv = []
+
         if args.tests:
             items += args.tests
         if args.submodule:
@@ -229,6 +236,7 @@ def main(argv):
         bench_args = []
         for a in items:
             bench_args.extend(['--bench', a])
+        bench_args.extend(extra_argv)
 
         if not args.bench_compare:
             cmd = ['asv', 'run', '-n', '-e', '--python=same'] + bench_args

plus maybe as an example in the initial help (it also doesn't list asv for --).

@seiko2plus if you think changing the script to pass -- is a good idea, do you want to do that? I assume nobody will mind, and since its an internal script, we can just finish this off quickly.

@seberg, alright I modified the patch with your proposal, it's more practical I guess. thank u!.

@seiko2plus sorry, since this is a dev thing, I think we should just do it. I pushed a commit to make things work with -- (i.e. everything after a -- is passed on and the -- iself is skipped, but actual benchmarks must be listed before the --). That seemed the most reasonable thing to me, although I am not sure asv actually uses any non -- args, so it may not matter.

@seberg, your changes make it more robust since it allows passing all tokens after -- even the ones that start with an only single dash.

For everyone else, since this only affects devlopment, and even then only the --bench option to runtests.py, I will just merge this soon I think.

EDIT: With that print removed obviously.

@seberg, thank you