With the default jitter options aarch64 CPU-based devices typically experience continuous high CPU utilisation for several minutes after rngd starts.
Accoring to the rng-tools issue #150[1] and comments[2],in order to address this, the following configuration changes have been made, those configurations also can be found on Alpine Linux[3]: - reduce the number of threads used to 1 in total, rather than 1 per core. - reduce the buffer size from 16535 to 4133 which reduces the time taken to fill the buffer (and so reduces the duration of CPU load). [1] https://github.com/nhorman/rng-tools/issues/150 [2] https://github.com/nhorman/rng-tools/issues/150#issuecomment-953079212 [3] https://git.alpinelinux.org/aports/tree/main/rng-tools/rngd.confd-arm Signed-off-by: Xiangyu Chen <[email protected]> --- Changes in V2: *put the aarch64 specific default file in meta/recipes-support/rng-tools/rng-tools/aarch64 --- .../rng-tools/rng-tools/aarch64/default | 11 +++++++++++ 1 file changed, 11 insertions(+) create mode 100644 meta/recipes-support/rng-tools/rng-tools/aarch64/default diff --git a/meta/recipes-support/rng-tools/rng-tools/aarch64/default b/meta/recipes-support/rng-tools/rng-tools/aarch64/default new file mode 100644 index 0000000000..5a2fbcc9ef --- /dev/null +++ b/meta/recipes-support/rng-tools/rng-tools/aarch64/default @@ -0,0 +1,11 @@ +# With the default jitter options Arm CPU-based devices typically experience +# continuous high CPU utilisation for several minutes after rngd starts. +# See https://gitlab.alpinelinux.org/alpine/aports/-/issues/13035 and +# https://github.com/nhorman/rng-tools/issues/150 +# In order to address this the following configuration changes have been made: +# +# - reduce the number of threads used to 1 in total, rather than 1 per core. +# - reduce the buffer size from 16535 to 4133 which reduces the time taken +# to fill the buffer (and so reduces the duration of CPU load). +# +EXTRA_ARGS="-r /dev/hwrng -O jitter:buffer_size:4133 -O jitter:refill_thresh:4133 -O jitter:thread_count:1" -- 2.34.1
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