| Message ID | 20190320234806.19748-1-atish.patra@wdc.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | Unify CPU topology across ARM & RISC-V | expand |
On 3/20/19 4:48 PM, Atish Patra wrote: > The cpu-map DT entry in ARM can describe the CPU topology in much better > way compared to other existing approaches. RISC-V can easily adopt this > binding to represent its own CPU topology. Thus, both cpu-map DT > binding and topology parsing code can be moved to a common location so > that RISC-V or any other architecture can leverage that. > > The relevant discussion regarding unifying cpu topology can be found in > [1]. > > arch_topology seems to be a perfect place to move the common code. I > have not introduced any significant functional changes in the moved code. > The only downside in this approach is that the capacity code will be > executed for RISC-V as well. But, it will exit immediately after not > able to find the appropriate DT node. If the overhead is considered too > much, we can always compile out capacity related functions under a > different config for the architectures that do not support them. > > There was an opportunity to unify topology data structure for ARM32 done > by patch 3/4. But, I refrained from making any other changes as I am not > very well versed with original intention for some functions that > are present in arch_topology.c. I hope this patch series can be served > as a baseline for such changes in the future. > > The patches have been tested for RISC-V and compile tested for ARM64, > ARM32 & x86. > > The socket change[2] is also now part of this series. > > [1] https://lkml.org/lkml/2018/11/6/19 > [2] https://lkml.org/lkml/2018/11/7/918 > > QEMU changes for RISC-V topology are available at > > https://github.com/atishp04/qemu/tree/riscv_topology_dt > > HiFive Unleashed DT with topology node is available here. > https://github.com/atishp04/opensbi/tree/HiFive_unleashed_topology > > It can be verified with OpenSBI with following additional compile time > option. > > FW_PAYLOAD_FDT="unleashed_topology.dtb" > > Changes from v2->v3 > 1. Cover letter update with experiment DT for topology changes. > 2. Added the patch for [2]. > > Changes from v1->v2 > 1. ARM32 can now use the common code as well. > > Atish Patra (4): > dt-binding: cpu-topology: Move cpu-map to a common binding. > cpu-topology: Move cpu topology code to common code. > arm: Use common cpu_topology > RISC-V: Parse cpu topology during boot. > > Sudeep Holla (1): > Documentation: DT: arm: add support for sockets defining package > boundaries > > .../topology.txt => cpu/cpu-topology.txt} | 134 ++++++-- > arch/arm/include/asm/topology.h | 22 +- > arch/arm/kernel/topology.c | 10 +- > arch/arm64/include/asm/topology.h | 23 -- > arch/arm64/kernel/topology.c | 303 +----------------- > arch/riscv/Kconfig | 1 + > arch/riscv/kernel/smpboot.c | 3 + > drivers/base/arch_topology.c | 298 ++++++++++++++++- > drivers/base/topology.c | 1 + > include/linux/arch_topology.h | 36 +++ > 10 files changed, 453 insertions(+), 378 deletions(-) > rename Documentation/devicetree/bindings/{arm/topology.txt => cpu/cpu-topology.txt} (66%) > > -- > 2.21.0 > > Ping? Specifically, patch 3 & 4 affects ARM & ARM64. Any tests on real hardware would be great. Regards, Atish
On Wed, Apr 10, 2019 at 03:49:54PM -0700, Atish Patra wrote: [...] > > Ping? > Sorry for the delay(was off for a while), will take a look next week. > Specifically, patch 3 & 4 affects ARM & ARM64. Any tests on real hardware > would be great. > Sure. -- Regards, Sudeep
The cpu-map DT entry in ARM can describe the CPU topology in much better way compared to other existing approaches. RISC-V can easily adopt this binding to represent its own CPU topology. Thus, both cpu-map DT binding and topology parsing code can be moved to a common location so that RISC-V or any other architecture can leverage that. The relevant discussion regarding unifying cpu topology can be found in [1]. arch_topology seems to be a perfect place to move the common code. I have not introduced any significant functional changes in the moved code. The only downside in this approach is that the capacity code will be executed for RISC-V as well. But, it will exit immediately after not able to find the appropriate DT node. If the overhead is considered too much, we can always compile out capacity related functions under a different config for the architectures that do not support them. There was an opportunity to unify topology data structure for ARM32 done by patch 3/4. But, I refrained from making any other changes as I am not very well versed with original intention for some functions that are present in arch_topology.c. I hope this patch series can be served as a baseline for such changes in the future. The patches have been tested for RISC-V and compile tested for ARM64, ARM32 & x86. The socket change[2] is also now part of this series. [1] https://lkml.org/lkml/2018/11/6/19 [2] https://lkml.org/lkml/2018/11/7/918 QEMU changes for RISC-V topology are available at https://github.com/atishp04/qemu/tree/riscv_topology_dt HiFive Unleashed DT with topology node is available here. https://github.com/atishp04/opensbi/tree/HiFive_unleashed_topology It can be verified with OpenSBI with following additional compile time option. FW_PAYLOAD_FDT="unleashed_topology.dtb" Changes from v2->v3 1. Cover letter update with experiment DT for topology changes. 2. Added the patch for [2]. Changes from v1->v2 1. ARM32 can now use the common code as well. Atish Patra (4): dt-binding: cpu-topology: Move cpu-map to a common binding. cpu-topology: Move cpu topology code to common code. arm: Use common cpu_topology RISC-V: Parse cpu topology during boot. Sudeep Holla (1): Documentation: DT: arm: add support for sockets defining package boundaries .../topology.txt => cpu/cpu-topology.txt} | 134 ++++++-- arch/arm/include/asm/topology.h | 22 +- arch/arm/kernel/topology.c | 10 +- arch/arm64/include/asm/topology.h | 23 -- arch/arm64/kernel/topology.c | 303 +----------------- arch/riscv/Kconfig | 1 + arch/riscv/kernel/smpboot.c | 3 + drivers/base/arch_topology.c | 298 ++++++++++++++++- drivers/base/topology.c | 1 + include/linux/arch_topology.h | 36 +++ 10 files changed, 453 insertions(+), 378 deletions(-) rename Documentation/devicetree/bindings/{arm/topology.txt => cpu/cpu-topology.txt} (66%) -- 2.21.0