diff --git a/docs/Benchmarks.md b/docs/Benchmarks.md
index faf2ed1b..7a418873 100644
--- a/docs/Benchmarks.md
+++ b/docs/Benchmarks.md
@@ -390,7 +390,7 @@ communication mechanism. The test is run using the console.py tool
 cut-and-paste into the console.py terminal window:
 ```
 DELAY {clock + 2*freq} get_uptime
-FLOOD 100000 0.0 end_group
+FLOOD 100000 0.0 debug_nop
 get_uptime
 ```
 
diff --git a/src/debugcmds.c b/src/debugcmds.c
index 22350c18..f1f2fb0f 100644
--- a/src/debugcmds.c
+++ b/src/debugcmds.c
@@ -1,48 +1,12 @@
 // Debugging commands.
 //
-// Copyright (C) 2016-2019  Kevin O'Connor <kevin@koconnor.net>
+// Copyright (C) 2016-2021  Kevin O'Connor <kevin@koconnor.net>
 //
 // This file may be distributed under the terms of the GNU GPLv3 license.
 
 #include "board/io.h" // readl
 #include "board/irq.h" // irq_save
 #include "command.h" // DECL_COMMAND
-#include "sched.h" // sched_add_timer
-
-
-/****************************************************************
- * Group commands
- ****************************************************************/
-
-static struct timer group_timer;
-
-static uint_fast8_t
-group_end_event(struct timer *timer)
-{
-    shutdown("Missed scheduling of next event");
-}
-
-void
-command_start_group(uint32_t *args)
-{
-    sched_del_timer(&group_timer);
-    group_timer.func = group_end_event;
-    group_timer.waketime = args[0];
-    sched_add_timer(&group_timer);
-}
-DECL_COMMAND(command_start_group, "start_group clock=%u");
-
-void
-command_end_group(uint32_t *args)
-{
-    sched_del_timer(&group_timer);
-}
-DECL_COMMAND(command_end_group, "end_group");
-
-
-/****************************************************************
- * Register debug commands
- ****************************************************************/
 
 void
 command_debug_read(uint32_t *args)
@@ -92,4 +56,4 @@ void
 command_debug_nop(uint32_t *args)
 {
 }
-DECL_COMMAND_FLAGS(command_debug_nop, HF_IN_SHUTDOWN, "debug_nop data=%*s");
+DECL_COMMAND_FLAGS(command_debug_nop, HF_IN_SHUTDOWN, "debug_nop");