[ECOS] Problem with CPU Load Measurements and gcc-arm-eabi optimization.

[ECOS] Problem with CPU Load Measurements and gcc-arm-eabi optimization.

[lesc]

Hello Everyone

I just encountered the Problem that the cyg_cpuload_create always 
delivers 100% on my System. After a bit of debugging I figured out, that 
the whole for-loop in idle_thread_main seems to be omitted.

I could fix this Problem with declaring 
idle_thread_loops[CYGNUM_KERNEL_CPU_MAX] as volatile (patch below). But 
this has maybe some consequences I am not thinking of, as the variables 
are now always synced to the ram and no kept in a CPU register.

Do you see any Problem with my approach?

Regards Serafin

Patch:

 From 2799f68a5e508c6bece6ec85b1e201282983b98d Mon Sep 17 00:00:00 2001
From: Serafin Leschke <lesc@zhaw.ch>
Date: Mon, 17 Nov 2014 13:51:23 +0100
Subject: [PATCH] declare idle_thread_loops as volatile

---
  packages/kernel/current/src/common/thread.cxx | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/kernel/current/src/common/thread.cxx 
b/packages/kernel/current/src/common/thread.cxx
index 86a3dc4..bd1aa99 100644
--- a/packages/kernel/current/src/common/thread.cxx
+++ b/packages/kernel/current/src/common/thread.cxx
@@ -1211,7 +1211,7 @@ Cyg_ThreadTimer::alarm(
  #endif // CYGNUM_HAL_STACK_SIZE_MINIMUM

  // Loop counter for debugging/housekeeping
-cyg_uint32 idle_thread_loops[CYGNUM_KERNEL_CPU_MAX];
+volatile cyg_uint32 idle_thread_loops[CYGNUM_KERNEL_CPU_MAX];

  static char 
idle_thread_stack[CYGNUM_KERNEL_CPU_MAX][CYGNUM_KERNEL_THREADS_IDLE_STACK_SIZE];

-- 
1.9.1


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AW: [ECOS] Problem with CPU Load Measurements and gcc-arm-eabi optimization.

[Richard Rauch]

Hello,

are you sure, that you are using current version of eCos?
This issue should be already solved. Current version has "volatile" keyword as you proposed!

Richard Rauch
www.itrgmbh.com


> -----Ursprüngliche Nachricht-----
> Von: ecos-discuss-owner@ecos.sourceware.org [mailto:ecos-discuss-
> owner@ecos.sourceware.org] Im Auftrag von lesc
> Gesendet: Montag, 17. November 2014 14:07
> An: eCos Discussion
> Betreff: [ECOS] Problem with CPU Load Measurements and gcc-arm-eabi
> optimization.
> 
> Hello Everyone
> 
> I just encountered the Problem that the cyg_cpuload_create always delivers
> 100% on my System. After a bit of debugging I figured out, that the whole
> for-loop in idle_thread_main seems to be omitted.
> 
> I could fix this Problem with declaring
> idle_thread_loops[CYGNUM_KERNEL_CPU_MAX] as volatile (patch below).
> But this has maybe some consequences I am not thinking of, as the variables
> are now always synced to the ram and no kept in a CPU register.
> 
> Do you see any Problem with my approach?
> 
> Regards Serafin
> 
> Patch:
> 
>  From 2799f68a5e508c6bece6ec85b1e201282983b98d Mon Sep 17 00:00:00
> 2001
> From: Serafin Leschke <lesc@zhaw.ch>
> Date: Mon, 17 Nov 2014 13:51:23 +0100
> Subject: [PATCH] declare idle_thread_loops as volatile
> 
> ---
>   packages/kernel/current/src/common/thread.cxx | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/packages/kernel/current/src/common/thread.cxx
> b/packages/kernel/current/src/common/thread.cxx
> index 86a3dc4..bd1aa99 100644
> --- a/packages/kernel/current/src/common/thread.cxx
> +++ b/packages/kernel/current/src/common/thread.cxx
> @@ -1211,7 +1211,7 @@ Cyg_ThreadTimer::alarm(
>   #endif // CYGNUM_HAL_STACK_SIZE_MINIMUM
> 
>   // Loop counter for debugging/housekeeping
> -cyg_uint32 idle_thread_loops[CYGNUM_KERNEL_CPU_MAX];
> +volatile cyg_uint32 idle_thread_loops[CYGNUM_KERNEL_CPU_MAX];
> 
>   static char
> idle_thread_stack[CYGNUM_KERNEL_CPU_MAX][CYGNUM_KERNEL_THREA
> DS_IDLE_STACK_SIZE];
> 
> --
> 1.9.1
> 
> 
> --
> Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos
> and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss



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Re: AW: [ECOS] Problem with CPU Load Measurements and gcc-arm-eabi optimization.

[lesc]

Hi Richard

Thanks for the fast answer. This is a little embarrassing, I managed to 
find the commit you are referring to:

http://hg-pub.ecoscentric.com/ecos/rev/041821fb5427

The Version of Ecos I (have to) use is a port for the Xilinx Zynq Platform:
  https://github.com/antmicro/ecos-mars-zx3
Why they not just make a ecos package for the hal - instead of forking - 
I don't know (I'm quite new to the industry). Their version seems to be 
built on the ecos-v3 branch in which the above mentioned commit does not 
seem to me merged:
http://hg-pub.ecoscentric.com/ecos-v3_0-branch/file/7d8c61e6225c/packages/kernel/current/src/common/thread.cxx

So maybe I should read a bit more about the ecos release model to find 
out which version I should use in future.

Serafin



On 17.11.2014 18:47, Richard Rauch wrote:
> Hello,
>
> are you sure, that you are using current version of eCos?
> This issue should be already solved. Current version has "volatile" keyword as you proposed!
>
> Richard Rauch
> www.itrgmbh.com
>
>
>> -----Ursprüngliche Nachricht-----
>> Von: ecos-discuss-owner@ecos.sourceware.org [mailto:ecos-discuss-
>> owner@ecos.sourceware.org] Im Auftrag von lesc
>> Gesendet: Montag, 17. November 2014 14:07
>> An: eCos Discussion
>> Betreff: [ECOS] Problem with CPU Load Measurements and gcc-arm-eabi
>> optimization.
>>
>> Hello Everyone
>>
>> I just encountered the Problem that the cyg_cpuload_create always delivers
>> 100% on my System. After a bit of debugging I figured out, that the whole
>> for-loop in idle_thread_main seems to be omitted.
>>
>> I could fix this Problem with declaring
>> idle_thread_loops[CYGNUM_KERNEL_CPU_MAX] as volatile (patch below).
>> But this has maybe some consequences I am not thinking of, as the variables
>> are now always synced to the ram and no kept in a CPU register.
>>
>> Do you see any Problem with my approach?
>>
>> Regards Serafin
>>
>> Patch:
>>
>>   From 2799f68a5e508c6bece6ec85b1e201282983b98d Mon Sep 17 00:00:00
>> 2001
>> From: Serafin Leschke <lesc@zhaw.ch>
>> Date: Mon, 17 Nov 2014 13:51:23 +0100
>> Subject: [PATCH] declare idle_thread_loops as volatile
>>
>> ---
>>    packages/kernel/current/src/common/thread.cxx | 2 +-
>>    1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/packages/kernel/current/src/common/thread.cxx
>> b/packages/kernel/current/src/common/thread.cxx
>> index 86a3dc4..bd1aa99 100644
>> --- a/packages/kernel/current/src/common/thread.cxx
>> +++ b/packages/kernel/current/src/common/thread.cxx
>> @@ -1211,7 +1211,7 @@ Cyg_ThreadTimer::alarm(
>>    #endif // CYGNUM_HAL_STACK_SIZE_MINIMUM
>>
>>    // Loop counter for debugging/housekeeping
>> -cyg_uint32 idle_thread_loops[CYGNUM_KERNEL_CPU_MAX];
>> +volatile cyg_uint32 idle_thread_loops[CYGNUM_KERNEL_CPU_MAX];
>>
>>    static char
>> idle_thread_stack[CYGNUM_KERNEL_CPU_MAX][CYGNUM_KERNEL_THREA
>> DS_IDLE_STACK_SIZE];
>>
>> --
>> 1.9.1
>>
>>
>> --
>> Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos
>> and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss
>

-- 
Serafin Leschke, BSc in Computer Sience UAS Zurich
Research Assistant

ZHAW, Zurich University of Applied Sciences
InES, Institute of Embedded Systems
Postfach
Technikumstr. 22
CH-8401 Winterthur
--
Tel: +41 58 934 69 79
Fax: +41 58 935 76 87
E-Mail: serafin.lescke@zhaw.ch
Web: http://ines.zhaw.ch
--


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