diff --git a/source/devices/AM62AX/linux/RT_Linux_Performance_Guide.rst b/source/devices/AM62AX/linux/RT_Linux_Performance_Guide.rst index 44eb553f7..67ff0fa2d 100644 --- a/source/devices/AM62AX/linux/RT_Linux_Performance_Guide.rst +++ b/source/devices/AM62AX/linux/RT_Linux_Performance_Guide.rst @@ -62,13 +62,20 @@ 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","CPU 2","CPU 3" diff --git a/source/devices/AM62LX/linux/RT_Linux_Performance_Guide.rst b/source/devices/AM62LX/linux/RT_Linux_Performance_Guide.rst index ab01f01af..390322bee 100644 --- a/source/devices/AM62LX/linux/RT_Linux_Performance_Guide.rst +++ b/source/devices/AM62LX/linux/RT_Linux_Performance_Guide.rst @@ -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" diff --git a/source/devices/AM62PX/linux/RT_Linux_Performance_Guide.rst b/source/devices/AM62PX/linux/RT_Linux_Performance_Guide.rst index d02ecea29..60f7f7471 100644 --- a/source/devices/AM62PX/linux/RT_Linux_Performance_Guide.rst +++ b/source/devices/AM62PX/linux/RT_Linux_Performance_Guide.rst @@ -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" diff --git a/source/devices/AM62X/linux/RT_Linux_Performance_Guide.rst b/source/devices/AM62X/linux/RT_Linux_Performance_Guide.rst index e835e18f1..37af72410 100644 --- a/source/devices/AM62X/linux/RT_Linux_Performance_Guide.rst +++ b/source/devices/AM62X/linux/RT_Linux_Performance_Guide.rst @@ -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"