For more than a decade, CONFIG_SCHED_DEBUG=y has been enabled
in all the major Linux distributions:

   /boot/config-6.11.0-19-generic:CONFIG_SCHED_DEBUG=y

The reason is that while originally CONFIG_SCHED_DEBUG started
out as a debugging feature, over the years (decades ...) it has
grown various bits of statistics, instrumentation and
control knobs that are useful for sysadmin and general software
development purposes as well.

But within the kernel we still pretend that there's a choice,
and sometimes code that is seemingly 'debug only' creates overhead
that should be optimized in reality.

So make it all official and make CONFIG_SCHED_DEBUG unconditional.

Now that all uses of CONFIG_SCHED_DEBUG are removed from
the code by previous patches, remove the Kconfig option as well.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 lib/Kconfig.debug | 9 ---------
 1 file changed, 9 deletions(-)

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 1af972a92d06..a2ab693d008d 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1301,15 +1301,6 @@ endmenu # "Debug lockups and hangs"
 
 menu "Scheduler Debugging"
 
-config SCHED_DEBUG
-	bool "Collect scheduler debugging info"
-	depends on DEBUG_KERNEL && DEBUG_FS
-	default y
-	help
-	  If you say Y here, the /sys/kernel/debug/sched file will be provided
-	  that can help debug the scheduler. The runtime overhead of this
-	  option is minimal.
-
 config SCHED_INFO
 	bool
 	default n
-- 
2.45.2

The following commit has been merged into the sched/core branch of tip:

Commit-ID:     b52173065e0aad82a31863bb5f63ebe46f7eb657
Gitweb:        https://git.kernel.org/tip/b52173065e0aad82a31863bb5f63ebe46f7eb657
Author:        Ingo Molnar <mingo@kernel.org>
AuthorDate:    Mon, 17 Mar 2025 11:42:56 +01:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Wed, 19 Mar 2025 22:23:24 +01:00

sched/debug: Remove CONFIG_SCHED_DEBUG

For more than a decade, CONFIG_SCHED_DEBUG=y has been enabled
in all the major Linux distributions:

   /boot/config-6.11.0-19-generic:CONFIG_SCHED_DEBUG=y

The reason is that while originally CONFIG_SCHED_DEBUG started
out as a debugging feature, over the years (decades ...) it has
grown various bits of statistics, instrumentation and
control knobs that are useful for sysadmin and general software
development purposes as well.

But within the kernel we still pretend that there's a choice,
and sometimes code that is seemingly 'debug only' creates overhead
that should be optimized in reality.

So make it all official and make CONFIG_SCHED_DEBUG unconditional.

Now that all uses of CONFIG_SCHED_DEBUG are removed from
the code by previous patches, remove the Kconfig option as well.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Shrikanth Hegde <sshegde@linux.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ben Segall <bsegall@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Valentin Schneider <vschneid@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20250317104257.3496611-6-mingo@kernel.org
---
 lib/Kconfig.debug |  9 ---------
 1 file changed, 9 deletions(-)

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 1af972a..a2ab693 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1301,15 +1301,6 @@ endmenu # "Debug lockups and hangs"
 
 menu "Scheduler Debugging"
 
-config SCHED_DEBUG
-	bool "Collect scheduler debugging info"
-	depends on DEBUG_KERNEL && DEBUG_FS
-	default y
-	help
-	  If you say Y here, the /sys/kernel/debug/sched file will be provided
-	  that can help debug the scheduler. The runtime overhead of this
-	  option is minimal.
-
 config SCHED_INFO
 	bool
 	default n

On Thu, Mar 20, 2025 at 08:59:56AM -0000, tip-bot2 for Ingo Molnar wrote:
> The following commit has been merged into the sched/core branch of tip:
> 
> Commit-ID:     b52173065e0aad82a31863bb5f63ebe46f7eb657
> Gitweb:        https://git.kernel.org/tip/b52173065e0aad82a31863bb5f63ebe46f7eb657
> Author:        Ingo Molnar <mingo@kernel.org>
> AuthorDate:    Mon, 17 Mar 2025 11:42:56 +01:00
> Committer:     Ingo Molnar <mingo@kernel.org>
> CommitterDate: Wed, 19 Mar 2025 22:23:24 +01:00
> 
> sched/debug: Remove CONFIG_SCHED_DEBUG
> 
> For more than a decade, CONFIG_SCHED_DEBUG=y has been enabled
> in all the major Linux distributions:
> 
>    /boot/config-6.11.0-19-generic:CONFIG_SCHED_DEBUG=y
> 
> The reason is that while originally CONFIG_SCHED_DEBUG started
> out as a debugging feature, over the years (decades ...) it has
> grown various bits of statistics, instrumentation and
> control knobs that are useful for sysadmin and general software
> development purposes as well.
> 
> But within the kernel we still pretend that there's a choice,
> and sometimes code that is seemingly 'debug only' creates overhead
> that should be optimized in reality.
> 
> So make it all official and make CONFIG_SCHED_DEBUG unconditional.
> 
> Now that all uses of CONFIG_SCHED_DEBUG are removed from
> the code by previous patches, remove the Kconfig option as well.


I really don't much like this :-(