The common believe that on the same hardware 64-bit must be better or equal to 32-bit is clearly wrong for the "crazy" BCM2711 chip used in Pi4. The detailed benchmarks for Raspian Buster are at 32 Bit Kernel 4.19 <http://ix.io/1MFf> and 64 Bit Kernel 5.4. <http://ix.io/2paq> showing for calculation AES 16KB 50% less throughput for 64-bit.
On my system I get similar results e.g. for AES-128 (16KB): Salsa Buster arm64 5.9.0 42'000 Ubuntu LTS armv7l 5.4 92'000 When playing a FullHD video coded H265, the average CPU load is 80% on 64-bit and less than 30% on 32-bit! Similar situations when encoding to H265 using ffmpeg . LinAdmin On 02.03.21 21:30, Arnd Bergmann wrote: > On Tue, Mar 2, 2021 at 7:51 PM LinAdmin <linad...@quickline.ch> wrote: > >>> There is really no good reason to run a 32-bit /kernel/ on the Pi 4, >>> especially the version >>> with 8GB RAM. While the bug should get fixed in principle to make the >>> default kernel >>> work and allow installing a 32-bit distro, the best setup for this >>> machine (especially >>> the versions with less than 4GB) is to use an armhf user space with a >>> 64-bit kernel. >> Benchmarking shows that the Pi4 with 32 bit kernel has about >> double performance compared to 64 bit kernel!!! > Can be more specific about what benchmarks and who ran them? > This seems highly unlikely. > > Arnd >
