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DISCUSSION Rodrigo Amestica 2 participants 4 messages Mar 19, 2009

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Rodrigo Amestica

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#0 lore raw

Hi,

general questions from somebody who's just starting to look into the preempt patch.

the article linked below makes direct reference to the behavior of the preempt rt patch. The article was written in 2007. How much of that still holds true in the current version of the patch?

I'm basically wondering about the first sentences in the abstract of that article. The big picture seems to be rather simple: calls to specific linux services could break the performance of a real time task by depending on lower priority tasks to complete that service.

Does this mean that one must always be alert to which system services are invoked during the execution of a real time task? Does the vanilla kernel or the preempt-rt patch tries to somehow detect this condition and alert somehow?

thanks,
Rodrigo

author
#1 lore raw

yes, i forgot to include the link. now it goes.

http://www.ddj.com/linux-open-source/200900827

Quoted 25 lines · Rodrigo Amestica

Hi,

general questions from somebody who's just starting to look into the preempt patch.

the article linked below makes direct reference to the behavior of the preempt rt patch. The article was written in 2007. How much of that still holds true in the current version of the patch?

I'm basically wondering about the first sentences in the abstract of that article. The big picture seems to be rather simple: calls to specific linux services could break the performance of a real time task by depending on lower priority tasks to complete that service.

Does this mean that one must always be alert to which system services are invoked during the execution of a real time task? Does the vanilla kernel or the preempt-rt patch tries to somehow detect this condition and alert somehow?

thanks,
Rodrigo

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#2 lore raw
Quoted 21 lines · Rodrigo Amestica

yes, i forgot to include the link. now it goes.

http://www.ddj.com/linux-open-source/200900827

Quoted 16 lines · Rodrigo Amestica

Hi,

general questions from somebody who's just starting to look into the preempt patch.

the article linked below makes direct reference to the behavior of the preempt rt patch. The article was written in 2007. How much of that still holds true in the current version of the patch?

I'm basically wondering about the first sentences in the abstract of that article. The big picture seems to be rather simple: calls to specific linux services could break the performance of a real time task by depending on lower priority tasks to complete that service.

Does this mean that one must always be alert to which system services are invoked during the execution of a real time task?

Yes.

Quoted 3 lines
Quoted 3 lines

Does the vanilla
kernel or the preempt-rt patch tries to somehow detect this condition and alert somehow?

I am not aware of any such test, but it sounds like an interesting idea.

Quoted 4 lines
Quoted 4 lines

thanks,
Rodrigo

#3 lore raw
In reply to Rodrigo Amestica
Quoted 6 lines · Rodrigo Amestica

Hi,

general questions from somebody who's just starting to look into the preempt patch.

the article linked below makes direct reference to the behavior of the

The link is missing.

Quoted 23 lines

preempt rt patch. The article was written in 2007. How much of that still holds true in the current version of the patch?

I'm basically wondering about the first sentences in the abstract of that article. The big picture seems to be rather simple: calls to specific linux services could break the performance of a real time task by depending on lower priority tasks to complete that service.

Does this mean that one must always be alert to which system services are invoked during the execution of a real time task? Does the vanilla kernel or the preempt-rt patch tries to somehow detect this condition and alert somehow?

thanks,
Rodrigo

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linux-rt-users" in
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