[PATCH v2] sched/deadline: fix runtime accounting in documentation

[PATCH v2] sched/deadline: fix runtime accounting in documentation

[Claudio Scordino]

Signed-off-by: Claudio Scordino <claudio@evidence.eu.com>
Signed-off-by: Luca Abeni <luca.abeni@santannapisa.it>
Acked-by: Daniel Bristot de Oliveira <bristot@redhat.com>
CC: Jonathan Corbet <corbet@lwn.net>
CC: "Peter Zijlstra (Intel)" <peterz@infradead.org>
CC: Ingo Molnar <mingo@redhat.com>
CC: linux-doc@vger.kernel.org
Cc: Tommaso Cucinotta <tommaso.cucinotta@sssup.it>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
---
 Documentation/scheduler/sched-deadline.txt | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/Documentation/scheduler/sched-deadline.txt b/Documentation/scheduler/sched-deadline.txt
index e89e36e..8ce78f8 100644
--- a/Documentation/scheduler/sched-deadline.txt
+++ b/Documentation/scheduler/sched-deadline.txt
@@ -204,10 +204,17 @@ CONTENTS
  It does so by decrementing the runtime of the executing task Ti at a pace equal
  to
 
-           dq = -max{ Ui, (1 - Uinact) } dt
+           dq = -max{ Ui / Umax, (1 - Uinact - Uextra) } dt
 
- where Uinact is the inactive utilization, computed as (this_bq - running_bw),
- and Ui is the bandwidth of task Ti.
+ where:
+
+  - Ui is the bandwidth of task Ti;
+  - Umax is the maximum reclaimable utilization (subjected to RT throttling
+    limits);
+  - Uinact is the (per runqueue) inactive utilization, computed as
+    (this_bq - running_bw);
+  - Uextra is the (per runqueue) extra reclaimable utilization
+    (subjected to RT throttling limits).
 
 
  Let's now see a trivial example of two deadline tasks with runtime equal
-- 
2.7.4

Re: [PATCH v2] sched/deadline: fix runtime accounting in documentation

[Mathieu Poirier]

Hi Claudio,

On 14 November 2017 at 04:19, Claudio Scordino <claudio@evidence.eu.com> wrote:
> Signed-off-by: Claudio Scordino <claudio@evidence.eu.com>
> Signed-off-by: Luca Abeni <luca.abeni@santannapisa.it>
> Acked-by: Daniel Bristot de Oliveira <bristot@redhat.com>
> CC: Jonathan Corbet <corbet@lwn.net>
> CC: "Peter Zijlstra (Intel)" <peterz@infradead.org>
> CC: Ingo Molnar <mingo@redhat.com>
> CC: linux-doc@vger.kernel.org
> Cc: Tommaso Cucinotta <tommaso.cucinotta@sssup.it>
> Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
> ---

Please add a short description for your change, even if it is trivial.


>  Documentation/scheduler/sched-deadline.txt | 13 ++++++++++---
>  1 file changed, 10 insertions(+), 3 deletions(-)
>
> diff --git a/Documentation/scheduler/sched-deadline.txt b/Documentation/scheduler/sched-deadline.txt
> index e89e36e..8ce78f8 100644
> --- a/Documentation/scheduler/sched-deadline.txt
> +++ b/Documentation/scheduler/sched-deadline.txt
> @@ -204,10 +204,17 @@ CONTENTS
>   It does so by decrementing the runtime of the executing task Ti at a pace equal
>   to
>
> -           dq = -max{ Ui, (1 - Uinact) } dt
> +           dq = -max{ Ui / Umax, (1 - Uinact - Uextra) } dt
>
> - where Uinact is the inactive utilization, computed as (this_bq - running_bw),
> - and Ui is the bandwidth of task Ti.
> + where:
> +
> +  - Ui is the bandwidth of task Ti;
> +  - Umax is the maximum reclaimable utilization (subjected to RT throttling
> +    limits);
> +  - Uinact is the (per runqueue) inactive utilization, computed as
> +    (this_bq - running_bw);
> +  - Uextra is the (per runqueue) extra reclaimable utilization
> +    (subjected to RT throttling limits).

I think there would be value in defining 'dq' and 'dt'.  That way
people know exactly what they are and it leaves no room for
interpretation.

Thanks,
Mathieu

>
>
>   Let's now see a trivial example of two deadline tasks with runtime equal
> --
> 2.7.4
>

Re: [PATCH v2] sched/deadline: fix runtime accounting in documentation

[Peter Zijlstra]

On Tue, Nov 14, 2017 at 12:19:26PM +0100, Claudio Scordino wrote:
> Signed-off-by: Claudio Scordino <claudio@evidence.eu.com>
> Signed-off-by: Luca Abeni <luca.abeni@santannapisa.it>
> Acked-by: Daniel Bristot de Oliveira <bristot@redhat.com>
> CC: Jonathan Corbet <corbet@lwn.net>
> CC: "Peter Zijlstra (Intel)" <peterz@infradead.org>
> CC: Ingo Molnar <mingo@redhat.com>
> CC: linux-doc@vger.kernel.org
> Cc: Tommaso Cucinotta <tommaso.cucinotta@sssup.it>
> Cc: Mathieu Poirier <mathieu.poirier@linaro.org>

ACK, Ingo can you route this?

> ---
>  Documentation/scheduler/sched-deadline.txt | 13 ++++++++++---
>  1 file changed, 10 insertions(+), 3 deletions(-)
> 
> diff --git a/Documentation/scheduler/sched-deadline.txt b/Documentation/scheduler/sched-deadline.txt
> index e89e36e..8ce78f8 100644
> --- a/Documentation/scheduler/sched-deadline.txt
> +++ b/Documentation/scheduler/sched-deadline.txt
> @@ -204,10 +204,17 @@ CONTENTS
>   It does so by decrementing the runtime of the executing task Ti at a pace equal
>   to
>  
> -           dq = -max{ Ui, (1 - Uinact) } dt
> +           dq = -max{ Ui / Umax, (1 - Uinact - Uextra) } dt
>  
> - where Uinact is the inactive utilization, computed as (this_bq - running_bw),
> - and Ui is the bandwidth of task Ti.
> + where:
> +
> +  - Ui is the bandwidth of task Ti;
> +  - Umax is the maximum reclaimable utilization (subjected to RT throttling
> +    limits);
> +  - Uinact is the (per runqueue) inactive utilization, computed as
> +    (this_bq - running_bw);
> +  - Uextra is the (per runqueue) extra reclaimable utilization
> +    (subjected to RT throttling limits).
>  
>  
>   Let's now see a trivial example of two deadline tasks with runtime equal
> -- 
> 2.7.4
> 

Re: [PATCH v2] sched/deadline: fix runtime accounting in documentation

[Ingo Molnar]

* Peter Zijlstra <peterz@infradead.org> wrote:

> On Tue, Nov 14, 2017 at 12:19:26PM +0100, Claudio Scordino wrote:
> > Signed-off-by: Claudio Scordino <claudio@evidence.eu.com>
> > Signed-off-by: Luca Abeni <luca.abeni@santannapisa.it>
> > Acked-by: Daniel Bristot de Oliveira <bristot@redhat.com>
> > CC: Jonathan Corbet <corbet@lwn.net>
> > CC: "Peter Zijlstra (Intel)" <peterz@infradead.org>
> > CC: Ingo Molnar <mingo@redhat.com>
> > CC: linux-doc@vger.kernel.org
> > Cc: Tommaso Cucinotta <tommaso.cucinotta@sssup.it>
> > Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
> 
> ACK, Ingo can you route this?

Yeah, I've applied it to tip:sched/urgent, should go upstream in a few days.

Thanks,

	Ingo

[tip:sched/urgent] sched/deadline: Fix the description of runtime accounting in the documentation

[tip-bot for Claudio Scordino]

Commit-ID:  5c0342ca7ef17220d8dd2da68d0d349c26ab19df
Gitweb:     https://git.kernel.org/tip/5c0342ca7ef17220d8dd2da68d0d349c26ab19df
Author:     Claudio Scordino <claudio@evidence.eu.com>
AuthorDate: Tue, 14 Nov 2017 12:19:26 +0100
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Thu, 16 Nov 2017 09:00:35 +0100

sched/deadline: Fix the description of runtime accounting in the documentation

Signed-off-by: Claudio Scordino <claudio@evidence.eu.com>
Signed-off-by: Luca Abeni <luca.abeni@santannapisa.it>
Acked-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tommaso Cucinotta <tommaso.cucinotta@sssup.it>
Cc: linux-doc@vger.kernel.org
Link: http://lkml.kernel.org/r/1510658366-28995-1-git-send-email-claudio@evidence.eu.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 Documentation/scheduler/sched-deadline.txt | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/Documentation/scheduler/sched-deadline.txt b/Documentation/scheduler/sched-deadline.txt
index e89e36e..8ce78f8 100644
--- a/Documentation/scheduler/sched-deadline.txt
+++ b/Documentation/scheduler/sched-deadline.txt
@@ -204,10 +204,17 @@ CONTENTS
  It does so by decrementing the runtime of the executing task Ti at a pace equal
  to
 
-           dq = -max{ Ui, (1 - Uinact) } dt
+           dq = -max{ Ui / Umax, (1 - Uinact - Uextra) } dt
 
- where Uinact is the inactive utilization, computed as (this_bq - running_bw),
- and Ui is the bandwidth of task Ti.
+ where:
+
+  - Ui is the bandwidth of task Ti;
+  - Umax is the maximum reclaimable utilization (subjected to RT throttling
+    limits);
+  - Uinact is the (per runqueue) inactive utilization, computed as
+    (this_bq - running_bw);
+  - Uextra is the (per runqueue) extra reclaimable utilization
+    (subjected to RT throttling limits).
 
 
  Let's now see a trivial example of two deadline tasks with runtime equal