DO_ZERO_OF_WORKSPACE missing?

Thomas Doerfler Thomas.Doerfler at embedded-brains.de
Sun Sep 21 19:08:12 UTC 2008


Hi Joel,

thank you, I really was confused.

wkr,
Thomas.

Joel Sherrill schrieb:
> Thomas Dörfler wrote:
>> Hello,
>>
>> during some testing of rtems-4.9-branch I came across a modification
>> that was made some time ago: The old Cpu_table field
>> "do_zero_of_workspace" was moved to the Configuration table and its
>> default initialization is now controlled using a BSP define called
>>
>> BSP_ZERO_WORKSPACE_AUTOMATICALLY
>>
>> This is generally ok.
>>
>> BUT: according to my grep results, this setting is used only in two BSPs
>> now: the arm/rtl22xx, and the powerpc/mvme5500
>>
>>   
> Sounds like it needs to be taken off of those two.
>> I really can't belive, that this setting is NOT required by other BSPs.
>> When browsing the various Changelogs (e.g. powerpc/Changelog) , I found
>> references that before these changes the default for
>> "do_zero_of_workspace" in bootcard.c was TRUE, now it is obviously FALSE
>> for most of the BSPs.
>>
>>   
> You must have missed this in the 4.8 release notes.  It was ready
> to be changed when 4.7 was branched but it felt too dangerous so
> was immediately made the default after branching 4.7.  It cut ~80%
> off the boot time on the BSPs I measured.
>> What did I miss? Why is "do_zero_of_workspace" no longer required for
>> most of the BSPs?
> Because we worked to ensure that all data fields are initialized
> EVERY time an object is created.  This eliminated the need to
> zero the workspace and depend on that.  Plus when you reuse
> an object control block, it is not zero the 2nd time around.
>> Is this a show-stopper for the 4.9.0 version?
>>
>>   
> It might have been an issue for 4.8.0 but we have been running
> this way a while now.
>> Any insights welcome!
>>
>> Thomas.
>>
>> -- 
>> --------------------------------------------
>> embedded brains GmbH
>> Thomas Doerfler           Obere Lagerstr. 30
>> D-82178 Puchheim          Germany
>> Tel. : +49-89-18 90 80 79-2
>> Fax  : +49-89-18 90 80 79-9
>> email: Thomas.Doerfler at embedded-brains.de
>> PGP public key available on request
>>
>> Diese Nachricht ist keine geschäftliche Mitteilung im Sinne des EHUG.
>>   
> 
> 


-- 
--------------------------------------------
Embedded Brains GmbH
Thomas Doerfler           Obere Lagerstr. 30
D-82178 Puchheim          Germany
email: Thomas.Doerfler at embedded-brains.de
Phone: +49-89-18908079-2
Fax:   +49-89-18908079-9



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