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

["Richard Rauch" <rrauch at itrgmbh dot de>]

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


> -----UrsprÃngliche 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
> 
> 
> --
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> and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss



--
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