| Message ID | 20220831122414.1660440-1-emil.renner.berthing@canonical.com |
|---|---|
| Headers | show |
| Series | Support up to 32 CPUs on riscv64 | expand |
On 8/31/22 06:24, Emil Renner Berthing wrote: > [Impact] > > * Currently our riscv64 kernels don't support more than 8 CPUs. > > * The QEMU 7.0 virt machine supports up to 512 virtual CPUs. > > * Raising CONFIG_NR_CPUS to the maximum of 32 allows us to use > more of them. > > [Test Plan] > > * Run riscv64 Ubuntu in a QEMU virt instance with more than 8 > virtual CPUs and see that only 8 of them are used. > > * After raising CONFIG_NR_CPUS up to 32 of them should be used. > > [Where problems could occur] > > * This will allocate slightly more RAM which might hurt very small > machines. > > Emil Renner Berthing (1): > UBUNTU: [Config] Raise riscv64 CONFIG_NR_CPUS to 32 > > debian.master/config/annotations | 2 +- > debian.master/config/riscv64/config.common.riscv64 | 2 +- > 2 files changed, 2 insertions(+), 2 deletions(-) > Acked-by: Tim Gardner <tim.gardner@canonical.com> Have you profiled memory usage to see how much more 512 would use ?
On Wed, 31 Aug 2022 at 15:26, Tim Gardner <tim.gardner@canonical.com> wrote: > > On 8/31/22 06:24, Emil Renner Berthing wrote: > > [Impact] > > > > * Currently our riscv64 kernels don't support more than 8 CPUs. > > > > * The QEMU 7.0 virt machine supports up to 512 virtual CPUs. > > > > * Raising CONFIG_NR_CPUS to the maximum of 32 allows us to use > > more of them. > > > > [Test Plan] > > > > * Run riscv64 Ubuntu in a QEMU virt instance with more than 8 > > virtual CPUs and see that only 8 of them are used. > > > > * After raising CONFIG_NR_CPUS up to 32 of them should be used. > > > > [Where problems could occur] > > > > * This will allocate slightly more RAM which might hurt very small > > machines. > > > > Emil Renner Berthing (1): > > UBUNTU: [Config] Raise riscv64 CONFIG_NR_CPUS to 32 > > > > debian.master/config/annotations | 2 +- > > debian.master/config/riscv64/config.common.riscv64 | 2 +- > > 2 files changed, 2 insertions(+), 2 deletions(-) > > > Acked-by: Tim Gardner <tim.gardner@canonical.com> > > Have you profiled memory usage to see how much more 512 would use ? No, because for now arch/riscv/Kconfig specifies "range 2 32" for CONFIG_NR_CPUS, so 32 is the maximum it allows until something like this patch is accepted: https://lore.kernel.org/all/20220420112408.155561-1-apatel@ventanamicro.com/ /Emil /Emil > -- > ----------- > Tim Gardner > Canonical, Inc
On Wed, Aug 31, 2022 at 02:24:13PM +0200, Emil Renner Berthing wrote: > [Impact] > > * Currently our riscv64 kernels don't support more than 8 CPUs. > > * The QEMU 7.0 virt machine supports up to 512 virtual CPUs. > > * Raising CONFIG_NR_CPUS to the maximum of 32 allows us to use > more of them.
On Wed, Aug 31, 2022 at 02:24:13PM +0200, Emil Renner Berthing wrote: > [Impact] > > * Currently our riscv64 kernels don't support more than 8 CPUs. > > * The QEMU 7.0 virt machine supports up to 512 virtual CPUs. > > * Raising CONFIG_NR_CPUS to the maximum of 32 allows us to use > more of them. > > [Test Plan] > > * Run riscv64 Ubuntu in a QEMU virt instance with more than 8 > virtual CPUs and see that only 8 of them are used. > > * After raising CONFIG_NR_CPUS up to 32 of them should be used. > > [Where problems could occur] > > * This will allocate slightly more RAM which might hurt very small > machines. Applied to kinetic/linux-unstable. Thanks, -Andrea