Le 2021-03-17 15:49, Wookey a écrit : > On 2021-03-17 14:52 +0100, Vincent Blut wrote: > > Control: tags -1 moreinfo > > > > Hi Wookey, > > > > Le 2021-01-27 12:57, Wookey a écrit : > > > Source: linux > > > Version: Please enable ARM CMN-600 power management on arm64 > > > Severity: normal > > > Tags: patch > > > > > > Current arm hardware such as graviton2 (AWS arm64 hardware) has > > > 'Coherent Mesh Network' interconnect (between components in a > > > soc). It's important that support for this is built in the kernel so > > > it can be used. > > > > > > This requires CONFIG_ARM_CMN=y > > > > Does it really have to be built-in instead of being provided as a module? > > Last I > > checked, Fedora and Ubuntu provide it as a module. > > No it should really be a module. Perf is driven from userspace so you > never need to use it before modules can be loaded.
Agreed. > I just did it like this because the other settings here are set as > built-ins too and this seemed less disruptive. (If we make it a module > we'll need to make sure it gets included in the right module package - > I'm not sure if that need tweaking somewhere else in the build system) > > I see that > CONFIG_THUNDERX2_PMU=y > CONFIG_ARM_SMMU_V3_PMU=y > are also set as builtins. That's probably wrong too. It seems your arm64 kernel config deviates from the one we provide in Debian. CONFIG_THUNDERX2_PMU is compiled as a module while CONFIG_ARM_SMMU_V3_PMU is not set, at least in linux 5.10.19-1. > […] > I also checked the state of the other perf configs with the arm kernel team > and got feedback that we have all the ones that should sensibly be set set > once > CONFIG_ARM_CMN=m > and > CONFIG_THUNDERX2_PMU=m > is added This means updating the arm64 kernel config to only include ARM_CMN as a module. To me it is acceptable for Bullseye as this seems uncontroversial, but note that I can't speak for the kernel team. > Upstream enables > CONFIG_FSL_IMX8_DDR_PMU=m > by default too. IMX8 hardware is available so we should probably turn this on > too Contrary to Ubuntu, we do not provide support for the i.MX8M SoC family, so enabling this option in the arm64 kernel config is not an option, right?
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