Major memory performance decline from u-boot to barebox

[Enrico Scholz]

Lucas Stach <l.stach at pengutronix.de> writes:

>> I have a karo tx6s module (imx6s, 512 MiB RAM) which is shipped with an
>> ancient u-boot 2015 bootloader.
>> 
>> barebox 2024.07 works out-of-the box on it. But under the booted linux
>> system a see a major regression in memory performance.
>
> The most likely cause is that Barebox applies the workaround for ARM
> erratum 845369, which has a major impact on streaming writes and thus
> both memset and memcpy performance. The old U-Boot probably does not
> include this workaround.
>
> You may check this theory by removing the call to
> enable_arm_errata_845369_war in imx6_cpu_lowlevel_init.

Thanks; after disabling this workaround, benchmarks are reporting high
numbers again.

Would it make sense to enable this workaround conditionally?  E.g. the
imx6s is not affected by this erratum because it has only one core and
no ACP.



Enrico