T1024 L2Cache

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T1024 L2Cache

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BharathiG
Contributor I

Need timing impact in setting and clearing of below bits by hardware. Will there be any variation in the timing with respect to environmental factor (temperature or electromagnetic effect).

1. After setting the L2IO and L2DO bits in L2CSR0, T1024 reference manual recommend the software to read these bits till it is set.  The time taken to wait for setting L2IO and L2DO is consistent for hardware, or it will be changing with variation of environmental factor (temperature or electromagnetic effect) or any other factors?

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2. After Setting L2FL bit to flush the cache, T1024 reference manual tells that bit will be cleared by hardware once the flush operation is done.  The time taken to clear this bit by the hardware for fixed cache size will it be consistent or different at varying temperatures and environmental conditions?

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3. After Setting L2FI bit to invalidate the cache, T1024 reference manual tells that bit will be cleared by hardware once the invalidate operation is done.  The time taken to clear this bit by the hardware for fixed cache size will it be consistent or different at varying temperatures and environmental conditionsBharathiG_2-1669000326504.png

4. Setting the L2E bit in L2CSR0 and waiting for this bit to be set by hardware.  The time taken to wait for setting L2E is consistent for hardware or it will be changing with variation of environmental factor (temperature or electromagnetic effect) or any other factors?

 

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The Above information will be useful to understand deterministic and consistent hardware behavior for a considered Software.

If the time is varying, is there any factor how much it varies?

 

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BharathiG
Contributor I

we are not seeing any strange behavior, it is working as expected. we need to consider this for Worst Case execution time, we are waiting for these bits to be set or clear. The Variation in timing with respect to external factors (temperature or electromagnetic effect) need to be considered for WCET. 

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yipingwang
NXP TechSupport
NXP TechSupport

Please refer to the following update from the AE team.

As I mentioned to you earlier we do not have any environment parameter correlation with wait time in our documentation. This means it is not a measured parameter that we have documented, So, I can not tell you the exact range of time nor environment interference impact on this time. So please tell customer that this is not a measured parameter that we have.

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BharathiG
Contributor I

Appreciate your response in this regards, as you cannot provide the exact range could you tell us the temperature has performance impact on this? if not exact what could be the theoretical or approximate range? 

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yipingwang
NXP TechSupport
NXP TechSupport

Please refer to the following update from the AE team.

Per last reply, our documentation never suggested a correlation of time to finish with temperature.

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yipingwang
NXP TechSupport
NXP TechSupport

Are you observing strange behavior?

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