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List:       openembedded-core
Subject:    Re: [OE-Core][kirkstone][master][PATCH] rng-tools: Add Arm aarch64 CPU specific configuration to add
From:       "Khem Raj" <raj.khem () gmail ! com>
Date:       2022-10-31 15:40:39
Message-ID: CAMKF1sq_Ubb3r+UtgZ651=wf-SFvkDW17cDzJ_us47oiGc6mZg () mail ! gmail ! com
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On Mon, Oct 31, 2022 at 12:51 AM Xiangyu Chen
<xiangyu.chen@windriver.com> wrote:
> 
> 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 <xiangyu.chen@windriver.com>
> ---
> .../rng-tools/rng-tools/default.aarch64               | 11 +++++++++++
> meta/recipes-support/rng-tools/rng-tools_6.15.bb      |  5 +++++
> 2 files changed, 16 insertions(+)
> create mode 100644 meta/recipes-support/rng-tools/rng-tools/default.aarch64
> 
> diff --git a/meta/recipes-support/rng-tools/rng-tools/default.aarch64 \
> b/meta/recipes-support/rng-tools/rng-tools/default.aarch64 new file mode 100644
> index 0000000000..5a2fbcc9ef
> --- /dev/null
> +++ b/meta/recipes-support/rng-tools/rng-tools/default.aarch64
> @@ -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"
> diff --git a/meta/recipes-support/rng-tools/rng-tools_6.15.bb \
> b/meta/recipes-support/rng-tools/rng-tools_6.15.bb index 0696351903..e1f6b2ad77 \
>                 100644
> --- a/meta/recipes-support/rng-tools/rng-tools_6.15.bb
> +++ b/meta/recipes-support/rng-tools/rng-tools_6.15.bb
> @@ -12,6 +12,7 @@ SRC_URI = \
> "git://github.com/nhorman/rng-tools.git;branch=master;protocol=https \ file://init \
> \ file://default \
> file://rngd.service \
> +           file://default.aarch64 \
> "
> SRCREV = "381f69828b782afda574f259c1b7549f48f9bb77"
> 
> @@ -59,3 +60,7 @@ do_install:append() {
> ${D}${systemd_system_unitdir}/rngd.service
> fi
> }
> +
> +do_install:append:aarch64() {
> +    install -Dm 0644 ${WORKDIR}/default.aarch64 \
> ${D}${sysconfdir}/default/rng-tools +}

Perhaps drop the aarch64 specific default file inside a folder called
aarch64 under meta/recipes-support/rng-tools/rng-tools
and we don't need any changes in recipe.

> --
> 2.34.1
> 
> 
> 
> 



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