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fix(rt-linux): Improve RT-Linux Performance Guide #507

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19 changes: 13 additions & 6 deletions source/devices/AM62AX/linux/RT_Linux_Performance_Guide.rst
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Expand Up @@ -62,13 +62,20 @@

.. note::

A known issue in this SDK release is affecting this benchmark.
Using OP-TEEs PRNG drivers rather than the hardware accelerated
TRNG drivers restores the context switch latencies to the values you
see here.
Using the OP-TEE TRNG driver can impact this benchmark's performance due to

Check warning on line 65 in source/devices/AM62AX/linux/RT_Linux_Performance_Guide.rst

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[vale] reported by reviewdog 🐶
[RedHat.Definitions] Define acronyms and abbreviations (such as 'TRNG') on first occurrence if they're likely to be unfamiliar.

Raw Output:
{"message": "[RedHat.Definitions] Define acronyms and abbreviations (such as 'TRNG') on first occurrence if they're likely to be unfamiliar.", "location": {"path": "source/devices/AM62AX/linux/RT_Linux_Performance_Guide.rst", "range": {"start": {"line": 65, "column": 21}}}, "severity": "INFO"}

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[vale] reported by reviewdog 🐶
[RedHat.Definitions] Define acronyms and abbreviations (such as 'TEE') on first occurrence if they're likely to be unfamiliar.

Raw Output:
{"message": "[RedHat.Definitions] Define acronyms and abbreviations (such as 'TEE') on first occurrence if they're likely to be unfamiliar.", "location": {"path": "source/devices/AM62AX/linux/RT_Linux_Performance_Guide.rst", "range": {"start": {"line": 65, "column": 17}}}, "severity": "INFO"}

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[vale] reported by reviewdog 🐶
[RedHat.SentenceLength] Try to keep sentences to an average of 32 words or fewer.

Raw Output:
{"message": "[RedHat.SentenceLength] Try to keep sentences to an average of 32 words or fewer.", "location": {"path": "source/devices/AM62AX/linux/RT_Linux_Performance_Guide.rst", "range": {"start": {"line": 65, "column": 4}}}, "severity": "INFO"}

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GitHub Actions / vale 

[vale] reported by reviewdog 🐶
[RedHat.Definitions] Define acronyms and abbreviations (such as 'TRNG') on first occurrence if they're likely to be unfamiliar.

Raw Output:
{"message": "[RedHat.Definitions] Define acronyms and abbreviations (such as 'TRNG') on first occurrence if they're likely to be unfamiliar.", "location": {"path": "source/devices/AM62AX/linux/RT_Linux_Performance_Guide.rst", "range": {"start": {"line": 65, "column": 21}}}, "severity": "INFO"}

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GitHub Actions / vale 

[vale] reported by reviewdog 🐶
[RedHat.Definitions] Define acronyms and abbreviations (such as 'TEE') on first occurrence if they're likely to be unfamiliar.

Raw Output:
{"message": "[RedHat.Definitions] Define acronyms and abbreviations (such as 'TEE') on first occurrence if they're likely to be unfamiliar.", "location": {"path": "source/devices/AM62AX/linux/RT_Linux_Performance_Guide.rst", "range": {"start": {"line": 65, "column": 17}}}, "severity": "INFO"}

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GitHub Actions / vale 

[vale] reported by reviewdog 🐶
[RedHat.SentenceLength] Try to keep sentences to an average of 32 words or fewer.

Raw Output:
{"message": "[RedHat.SentenceLength] Try to keep sentences to an average of 32 words or fewer.", "location": {"path": "source/devices/AM62AX/linux/RT_Linux_Performance_Guide.rst", "range": {"start": {"line": 65, "column": 4}}}, "severity": "INFO"}
frequent context switching between Normal World (Linux) and Secure World (OP-TEE),

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[vale] reported by reviewdog 🐶
[RedHat.Definitions] Define acronyms and abbreviations (such as 'TEE') on first occurrence if they're likely to be unfamiliar.

Raw Output:
{"message": "[RedHat.Definitions] Define acronyms and abbreviations (such as 'TEE') on first occurrence if they're likely to be unfamiliar.", "location": {"path": "source/devices/AM62AX/linux/RT_Linux_Performance_Guide.rst", "range": {"start": {"line": 66, "column": 81}}}, "severity": "INFO"}

Check warning on line 66 in source/devices/AM62AX/linux/RT_Linux_Performance_Guide.rst

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GitHub Actions / vale 

[vale] reported by reviewdog 🐶
[RedHat.Definitions] Define acronyms and abbreviations (such as 'TEE') on first occurrence if they're likely to be unfamiliar.

Raw Output:
{"message": "[RedHat.Definitions] Define acronyms and abbreviations (such as 'TEE') on first occurrence if they're likely to be unfamiliar.", "location": {"path": "source/devices/AM62AX/linux/RT_Linux_Performance_Guide.rst", "range": {"start": {"line": 66, "column": 81}}}, "severity": "INFO"}
which occurs when the kernel's hardware random number generator interface

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[vale] reported by reviewdog 🐶
[RedHat.TermsSuggestions] Depending on the context, consider using 'that' or ', which' rather than 'which'.

Raw Output:
{"message": "[RedHat.TermsSuggestions] Depending on the context, consider using 'that' or ', which' rather than 'which'.", "location": {"path": "source/devices/AM62AX/linux/RT_Linux_Performance_Guide.rst", "range": {"start": {"line": 67, "column": 4}}}, "severity": "INFO"}

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GitHub Actions / vale 

[vale] reported by reviewdog 🐶
[RedHat.TermsSuggestions] Depending on the context, consider using 'that' or ', which' rather than 'which'.

Raw Output:
{"message": "[RedHat.TermsSuggestions] Depending on the context, consider using 'that' or ', which' rather than 'which'.", "location": {"path": "source/devices/AM62AX/linux/RT_Linux_Performance_Guide.rst", "range": {"start": {"line": 67, "column": 4}}}, "severity": "INFO"}
(hwrng) requests entropy from the secure TRNG to replenish the Linux entropy

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[vale] reported by reviewdog 🐶
[RedHat.Definitions] Define acronyms and abbreviations (such as 'TRNG') on first occurrence if they're likely to be unfamiliar.

Raw Output:
{"message": "[RedHat.Definitions] Define acronyms and abbreviations (such as 'TRNG') on first occurrence if they're likely to be unfamiliar.", "location": {"path": "source/devices/AM62AX/linux/RT_Linux_Performance_Guide.rst", "range": {"start": {"line": 68, "column": 45}}}, "severity": "INFO"}

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GitHub Actions / vale 

[vale] reported by reviewdog 🐶
[RedHat.Spelling] Verify the word 'hwrng'. It is not in the American English spelling dictionary used by Vale.

Raw Output:
{"message": "[RedHat.Spelling] Verify the word 'hwrng'. It is not in the American English spelling dictionary used by Vale.", "location": {"path": "source/devices/AM62AX/linux/RT_Linux_Performance_Guide.rst", "range": {"start": {"line": 68, "column": 5}}}, "severity": "WARNING"}

Check warning on line 68 in source/devices/AM62AX/linux/RT_Linux_Performance_Guide.rst

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GitHub Actions / vale 

[vale] reported by reviewdog 🐶
[RedHat.Definitions] Define acronyms and abbreviations (such as 'TRNG') on first occurrence if they're likely to be unfamiliar.

Raw Output:
{"message": "[RedHat.Definitions] Define acronyms and abbreviations (such as 'TRNG') on first occurrence if they're likely to be unfamiliar.", "location": {"path": "source/devices/AM62AX/linux/RT_Linux_Performance_Guide.rst", "range": {"start": {"line": 68, "column": 45}}}, "severity": "INFO"}

Check warning on line 68 in source/devices/AM62AX/linux/RT_Linux_Performance_Guide.rst

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GitHub Actions / vale 

[vale] reported by reviewdog 🐶
[RedHat.Spelling] Verify the word 'hwrng'. It is not in the American English spelling dictionary used by Vale.

Raw Output:
{"message": "[RedHat.Spelling] Verify the word 'hwrng'. It is not in the American English spelling dictionary used by Vale.", "location": {"path": "source/devices/AM62AX/linux/RT_Linux_Performance_Guide.rst", "range": {"start": {"line": 68, "column": 5}}}, "severity": "WARNING"}
pool.

More information on switching to the PRNG drivers can be found in the
Foundational Components section, here :ref:`building-optee-with-prng`
The alternatives that can be taken to avoid the above latency spikes are:

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[vale] reported by reviewdog 🐶
[RedHat.TermsSuggestions] Depending on the context, consider using 'earlier', 'previous', 'preceding', or 'before' rather than 'above'.

Raw Output:
{"message": "[RedHat.TermsSuggestions] Depending on the context, consider using 'earlier', 'previous', 'preceding', or 'before' rather than 'above'.", "location": {"path": "source/devices/AM62AX/linux/RT_Linux_Performance_Guide.rst", "range": {"start": {"line": 71, "column": 52}}}, "severity": "INFO"}

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GitHub Actions / vale 

[vale] reported by reviewdog 🐶
[RedHat.PassiveVoice] 'be taken' is passive voice. In general, use active voice. Consult the style guide for acceptable use of passive voice.

Raw Output:
{"message": "[RedHat.PassiveVoice] 'be taken' is passive voice. In general, use active voice. Consult the style guide for acceptable use of passive voice.", "location": {"path": "source/devices/AM62AX/linux/RT_Linux_Performance_Guide.rst", "range": {"start": {"line": 71, "column": 30}}}, "severity": "INFO"}

Check warning on line 71 in source/devices/AM62AX/linux/RT_Linux_Performance_Guide.rst

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GitHub Actions / vale 

[vale] reported by reviewdog 🐶
[RedHat.SimpleWords] Use simple language. Consider using 'choices' or 'options' rather than 'alternatives'.

Raw Output:
{"message": "[RedHat.SimpleWords] Use simple language. Consider using 'choices' or 'options' rather than 'alternatives'.", "location": {"path": "source/devices/AM62AX/linux/RT_Linux_Performance_Guide.rst", "range": {"start": {"line": 71, "column": 8}}}, "severity": "INFO"}

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GitHub Actions / vale 

[vale] reported by reviewdog 🐶
[RedHat.TermsSuggestions] Depending on the context, consider using 'earlier', 'previous', 'preceding', or 'before' rather than 'above'.

Raw Output:
{"message": "[RedHat.TermsSuggestions] Depending on the context, consider using 'earlier', 'previous', 'preceding', or 'before' rather than 'above'.", "location": {"path": "source/devices/AM62AX/linux/RT_Linux_Performance_Guide.rst", "range": {"start": {"line": 71, "column": 52}}}, "severity": "INFO"}

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GitHub Actions / vale 

[vale] reported by reviewdog 🐶
[RedHat.PassiveVoice] 'be taken' is passive voice. In general, use active voice. Consult the style guide for acceptable use of passive voice.

Raw Output:
{"message": "[RedHat.PassiveVoice] 'be taken' is passive voice. In general, use active voice. Consult the style guide for acceptable use of passive voice.", "location": {"path": "source/devices/AM62AX/linux/RT_Linux_Performance_Guide.rst", "range": {"start": {"line": 71, "column": 30}}}, "severity": "INFO"}

Check warning on line 71 in source/devices/AM62AX/linux/RT_Linux_Performance_Guide.rst

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GitHub Actions / vale 

[vale] reported by reviewdog 🐶
[RedHat.SimpleWords] Use simple language. Consider using 'choices' or 'options' rather than 'alternatives'.

Raw Output:
{"message": "[RedHat.SimpleWords] Use simple language. Consider using 'choices' or 'options' rather than 'alternatives'.", "location": {"path": "source/devices/AM62AX/linux/RT_Linux_Performance_Guide.rst", "range": {"start": {"line": 71, "column": 8}}}, "severity": "INFO"}

- Instead of TRNG, use the Software PRNG driver in OP-TEE. More information
on switching to the PRNG driver can be found in the Foundational
Components section: :ref:`building-optee-with-prng`

- Use a Linux Kernel-based TRNG driver, which involves disabling TRNG
in OP-TEE and enabling the RNG node in the Kernel device tree

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@ti-kamlesh ti-kamlesh Nov 6, 2025

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provide only one option (disable TRNG from OPTEE, i.e. PRNG=y and enable TRNG in Linux, as discussed)

.. csv-table::
:header: "Latencies","CPU 0","CPU 1","CPU 2","CPU 3"
Expand Down
19 changes: 13 additions & 6 deletions source/devices/AM62LX/linux/RT_Linux_Performance_Guide.rst
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -61,13 +61,20 @@ default SDK image:

.. note::

A known issue in this SDK release is affecting this benchmark.
Using OP-TEEs PRNG drivers rather than the hardware accelerated TRNG
drivers restores the context switch latencies to the values you see
here.
Using the OP-TEE TRNG driver can impact this benchmark's performance due to
frequent context switching between Normal World (Linux) and Secure World (OP-TEE),
which occurs when the kernel's hardware random number generator interface
(hwrng) requests entropy from the secure TRNG to replenish the Linux entropy
pool.

More information on switching to the PRNG drivers can be found in the
Foundational Components section, here :ref:`building-optee-with-prng`
The alternatives that can be taken to avoid the above latency spikes are:

- Instead of TRNG, use the Software PRNG driver in OP-TEE. More information
on switching to the PRNG driver can be found in the Foundational
Components section: :ref:`building-optee-with-prng`

- Use a Linux Kernel-based TRNG driver, which involves disabling TRNG
in OP-TEE and enabling the RNG node in the Kernel device tree

.. csv-table::
:header: "Latencies","CPU 0","CPU 1"
Expand Down
18 changes: 12 additions & 6 deletions source/devices/AM62PX/linux/RT_Linux_Performance_Guide.rst
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -62,13 +62,19 @@ default SDK image

.. note::

A known issue in this SDK release is affecting this benchmark.
Using OP-TEEs PRNG drivers rather than the hardware accelerated TRNG
drivers restores the context switch latencies to the values you see
here.
Using the OP-TEE TRNG driver can impact this benchmark's performance due to
frequent context switching between Normal World (Linux) and Secure World (OP-TEE),
which occurs when the kernel's hardware random number generator interface
(hwrng) requests entropy from the secure TRNG to replenish the Linux entropy pool.

More information on switching to the PRNG drivers can be found in the
Foundational Components section, here :ref:`building-optee-with-prng`
The alternatives that can be taken to avoid the above latency spikes are:

- Instead of TRNG, use the Software PRNG driver in OP-TEE. More information
on switching to the PRNG driver can be found in the Foundational
Components section: :ref:`building-optee-with-prng`

- Use a Linux Kernel-based TRNG driver, which involves disabling TRNG
in OP-TEE and enabling the RNG node in the Kernel device tree

.. csv-table::
:header: "Latencies","CPU 0","CPU 1","CPU 2","CPU 3"
Expand Down
18 changes: 12 additions & 6 deletions source/devices/AM62X/linux/RT_Linux_Performance_Guide.rst
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -68,13 +68,19 @@ default SDK image using the SK-AM62B-P1_ reference board:

.. note::

A known issue in this SDK release is affecting this benchmark.
Using OP-TEE's PRNG drivers rather than the hardware accelerated TRNG
drivers restores the context switch latencies to the values you see
here.
Using the OP-TEE TRNG driver can impact this benchmark's performance due to
frequent context switching between Normal World (Linux) and Secure World (OP-TEE),
which occurs when the kernel's hardware random number generator interface
(hwrng) requests entropy from the secure TRNG to replenish the Linux entropy pool.

More information on switching to the PRNG drivers can be found in the
Foundational Components section, here :ref:`building-optee-with-prng`
The alternatives that can be taken to avoid the above latency spikes are:

- Instead of TRNG, use the Software PRNG driver in OP-TEE. More information
on switching to the PRNG driver can be found in the Foundational
Components section: :ref:`building-optee-with-prng`

- Use a Linux Kernel-based TRNG driver, which involves disabling TRNG
in OP-TEE and enabling the RNG node in the Kernel device tree

.. csv-table::
:header: "Latencies","CPU 0","CPU 1","CPU 2","CPU 3"
Expand Down
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