Hi, On Thu, Mar 5, 2020 at 9:07 AM Maulik Shah <mkshah@xxxxxxxxxxxxxx> wrote: > > Changes in v12: > - Kconfig change to remove COMPILE_TEST was dropped in v11, reinclude it. > > Changes in v11: > - Address Doug's comments on change 2 and 3 > - Include change to invalidate TCSes before flush from [4] > > Changes in v10: > - Address Evan's comments to update commit message on change 2 > - Add Evan's Reviewed by on change 2 > - Remove comment from rpmh_flush() related to last CPU invoking it > - Rebase all changes on top of next-20200302 > > Changes in v9: > - Keep rpmh_flush() to invoke from within cache_lock > - Remove comments related to only last cpu invoking rpmh_flush() > > Changes in v8: > - Address Stephen's comments on changes 2 and 3 > - Add Reviewed by from Stephen on change 1 > > Changes in v7: > - Address Srinivas's comments to update commit text > - Add Reviewed by from Srinivas > > Changes in v6: > - Drop 1 & 2 changes from v5 as they already landed in maintainer tree > - Drop 3 & 4 changes from v5 as no user at present for power domain in rsc > - Rename subject to appropriate since power domain changes are dropped > - Rebase other changes on top of next-20200221 > > Changes in v5: > - Add Rob's Acked by on dt-bindings change > - Drop firmware psci change > - Update cpuidle stats in dtsi to follow PC mode > - Include change to update dirty flag when data is updated from [4] > - Add change to invoke rpmh_flush when caches are dirty > > Changes in v4: > - Add change to allow hierarchical topology in PC mode > - Drop hierarchical domain idle states converter from v3 > - Address Merge sc7180 dtsi change to add low power modes > > Changes in v3: > - Address Rob's comment on dt property value > - Address Stephen's comments on rpmh-rsc driver change > - Include sc7180 cpuidle low power mode changes from [1] > - Include hierarchical domain idle states converter change from [2] > > Changes in v2: > - Add Stephen's Reviewed-By to the first three patches > - Addressed Stephen's comments on fourth patch > - Include changes to connect rpmh domain to cpuidle and genpds > > Resource State Coordinator (RSC) is responsible for powering off/lowering > the requirements from CPU subsystem for the associated hardware like buses, > clocks, and regulators when all CPUs and cluster is powered down. > > RSC power domain uses last-man activities provided by genpd framework based > on Ulf Hansoon's patch series[3], when the cluster of CPUs enter deepest > idle states. As a part of domain poweroff, RSC can lower resource state > requirements by flushing the cached sleep and wake state votes for various > resources. > > [1] https://patchwork.kernel.org/patch/11218965 > [2] https://patchwork.kernel.org/patch/10941671 > [3] https://patchwork.kernel.org/project/linux-arm-msm/list/?series=222355 > [4] https://patchwork.kernel.org/project/linux-arm-msm/list/?series=236503 > > Maulik Shah (3): > arm64: dts: qcom: sc7180: Add cpuidle low power states > soc: qcom: rpmh: Update dirty flag only when data changes > soc: qcom: rpmh: Invoke rpmh_flush for dirty caches > > arch/arm64/boot/dts/qcom/sc7180.dtsi | 78 ++++++++++++++++++++++++++++++++++++ > drivers/soc/qcom/rpmh.c | 27 ++++++++++--- > 2 files changed, 100 insertions(+), 5 deletions(-) One overall optimization idea? Should we add two API calls: rpmh_start_operations() rpmh_end_operations() These optional API calls would be an optimization a client could use. When rpmh_start_operations() is called then RPMH code will inhibit flushing (but will still update the "dirty" flag). When rpmh_end_operations() is called then the RPMH will flush if the dirty flag is set. This is a pretty simple concept but should have a huge impact in the number of times we program hardware in non-OSI mode. Specifically, if we don't do that and we look at what happens in the interconnect code: 1. We "invalidate" the batch. We have to flush the non-batch commands back into the hardware. 2. We program the "wake only" commands. We have to flush the batch wake-only commands and also the non-batch commands back into the hardware. 3. We program the "sleep only" commands. We have to flush yet again with everything. -Doug
