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Nov 10, 2025
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fix(rt-linux): Improve RT-Linux Performance Guide #508

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18 changes: 11 additions & 7 deletions source/devices/AM62AX/linux/RT_Linux_Performance_Guide.rst
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Original file line number Diff line number Diff line change
Expand Up @@ -62,13 +62,17 @@

.. 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.

More information on switching to the PRNG drivers can be found in the
Foundational Components section, here :ref:`building-optee-with-prng`
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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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"}

Check warning on line 65 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": 65, "column": 17}}}, "severity": "INFO"}

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

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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),

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"}
that occurs when the kernel's hardware random number generator interface
(hwrng) requests entropy from the secure TRNG to replenish the Linux entropy

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

View workflow job for this annotation

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.

The Linux TRNG driver can mitigate these latency spikes. This involves

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.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": 71, "column": 61}}}, "severity": "INFO"}

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

View workflow job for this annotation

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": 71, "column": 14}}}, "severity": "INFO"}
enabling the Pseudo RNG driver in OP-TEE as documented in the Foundational

Check warning on line 72 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": 72, "column": 41}}}, "severity": "INFO"}

Check warning on line 72 in source/devices/AM62AX/linux/RT_Linux_Performance_Guide.rst

View workflow job for this annotation

GitHub Actions / vale 

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

Raw Output:
{"message": "[RedHat.Definitions] Define acronyms and abbreviations (such as 'RNG') on first occurrence if they're likely to be unfamiliar.", "location": {"path": "source/devices/AM62AX/linux/RT_Linux_Performance_Guide.rst", "range": {"start": {"line": 72, "column": 24}}}, "severity": "INFO"}
Components section: :ref:`building-optee-with-prng`, and enabling the RNG
node in the Linux kernel device tree. This way the HW TRNG is accessed from
the kernel itself.

.. csv-table::
:header: "Latencies","CPU 0","CPU 1","CPU 2","CPU 3"
Expand Down
18 changes: 11 additions & 7 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 +61,17 @@ 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.

More information on switching to the PRNG drivers can be found in the
Foundational Components section, here :ref:`building-optee-with-prng`
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),
that occurs when the kernel's hardware random number generator interface
(hwrng) requests entropy from the secure TRNG to replenish the Linux entropy
pool.

The Linux TRNG driver can mitigate these latency spikes. This involves
enabling the Pseudo RNG driver in OP-TEE as documented in the Foundational
Components section: :ref:`building-optee-with-prng`, and enabling the RNG
node in the Linux kernel device tree. This way the HW TRNG is accessed from
the kernel itself.

.. csv-table::
:header: "Latencies","CPU 0","CPU 1"
Expand Down
18 changes: 11 additions & 7 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 +62,17 @@ 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.

More information on switching to the PRNG drivers can be found in the
Foundational Components section, here :ref:`building-optee-with-prng`
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),
that occurs when the kernel's hardware random number generator interface
(hwrng) requests entropy from the secure TRNG to replenish the Linux entropy
pool.

The Linux TRNG driver can mitigate these latency spikes. This involves
enabling the Pseudo RNG driver in OP-TEE as documented in the Foundational
Components section: :ref:`building-optee-with-prng`, and enabling the RNG
node in the Linux kernel device tree. This way the HW TRNG is accessed from
the kernel itself.

.. csv-table::
:header: "Latencies","CPU 0","CPU 1","CPU 2","CPU 3"
Expand Down
18 changes: 11 additions & 7 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 +68,17 @@ 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.

More information on switching to the PRNG drivers can be found in the
Foundational Components section, here :ref:`building-optee-with-prng`
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),
that occurs when the kernel's hardware random number generator interface
(hwrng) requests entropy from the secure TRNG to replenish the Linux entropy
pool.

The Linux TRNG driver can mitigate these latency spikes. This involves
enabling the Pseudo RNG driver in OP-TEE as documented in the Foundational
Components section: :ref:`building-optee-with-prng`, and enabling the RNG
node in the Linux kernel device tree. This way the HW TRNG is accessed from
the kernel itself.

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