This patchset enables the usage of haltpoll governer on arm64. This is
specifically interesting for KVM guests by reducing the IPC latencies.
Here are some benchmarks without/with haltpoll for a KVM guest:
a) without haltpoll:
perf bench sched pipe
# Running 'sched/pipe' benchmark:
# Executed 1000000 pipe operations between two processes
Total time: 8.138 [sec]
8.138094 usecs/op
122878 ops/sec
b) with haltpoll:
perf bench sched pipe
# Running 'sched/pipe' benchmark:
# Executed 1000000 pipe operations between two processes
Total time: 5.003 [sec]
5.003085 usecs/op
199876 ops/sec
v2 changes from v1:
- added patch 7 where we change cpu_relax with smp_cond_load_relaxed per PeterZ
(this improves by 50% at least the CPU cycles consumed in the tests above:
10,716,881,137 now vs 14,503,014,257 before)
- removed the ifdef from patch 1 per RafaelW
Joao Martins (6):
x86: Move ARCH_HAS_CPU_RELAX to arch
x86/kvm: Move haltpoll_want() to be arch defined
governors/haltpoll: Drop kvm_para_available() check
arm64: Select ARCH_HAS_CPU_RELAX
arm64: Define TIF_POLLING_NRFLAG
cpuidle-haltpoll: ARM64 support
Mihai Carabas (1):
cpuidle/poll_state: replace cpu_relax with smp_cond_load_relaxed
arch/Kconfig | 3 +++
arch/arm64/Kconfig | 1 +
arch/arm64/include/asm/thread_info.h | 6 ++++++
arch/x86/Kconfig | 1 +
arch/x86/include/asm/cpuidle_haltpoll.h | 1 +
arch/x86/kernel/kvm.c | 10 ++++++++++
drivers/cpuidle/Kconfig | 4 ++--
drivers/cpuidle/cpuidle-haltpoll.c | 8 ++------
drivers/cpuidle/governors/haltpoll.c | 5 +----
drivers/cpuidle/poll_state.c | 14 +++++++++-----
include/linux/cpuidle_haltpoll.h | 5 +++++
11 files changed, 41 insertions(+), 17 deletions(-)
--
1.8.3.1
Hello,
How can we move this patchset forward?
Thank you,
Mihai
La 20.11.2023 16:01, Mihai Carabas a scris:
> This patchset enables the usage of haltpoll governer on arm64. This is
> specifically interesting for KVM guests by reducing the IPC latencies.
>
> Here are some benchmarks without/with haltpoll for a KVM guest:
>
> a) without haltpoll:
> perf bench sched pipe
> # Running 'sched/pipe' benchmark:
> # Executed 1000000 pipe operations between two processes
>
> Total time: 8.138 [sec]
>
> 8.138094 usecs/op
> 122878 ops/sec
>
> b) with haltpoll:
> perf bench sched pipe
> # Running 'sched/pipe' benchmark:
> # Executed 1000000 pipe operations between two processes
>
> Total time: 5.003 [sec]
>
> 5.003085 usecs/op
> 199876 ops/sec
>
> v2 changes from v1:
> - added patch 7 where we change cpu_relax with smp_cond_load_relaxed per PeterZ
> (this improves by 50% at least the CPU cycles consumed in the tests above:
> 10,716,881,137 now vs 14,503,014,257 before)
> - removed the ifdef from patch 1 per RafaelW
>
>
> Joao Martins (6):
> x86: Move ARCH_HAS_CPU_RELAX to arch
> x86/kvm: Move haltpoll_want() to be arch defined
> governors/haltpoll: Drop kvm_para_available() check
> arm64: Select ARCH_HAS_CPU_RELAX
> arm64: Define TIF_POLLING_NRFLAG
> cpuidle-haltpoll: ARM64 support
>
> Mihai Carabas (1):
> cpuidle/poll_state: replace cpu_relax with smp_cond_load_relaxed
>
> arch/Kconfig | 3 +++
> arch/arm64/Kconfig | 1 +
> arch/arm64/include/asm/thread_info.h | 6 ++++++
> arch/x86/Kconfig | 1 +
> arch/x86/include/asm/cpuidle_haltpoll.h | 1 +
> arch/x86/kernel/kvm.c | 10 ++++++++++
> drivers/cpuidle/Kconfig | 4 ++--
> drivers/cpuidle/cpuidle-haltpoll.c | 8 ++------
> drivers/cpuidle/governors/haltpoll.c | 5 +----
> drivers/cpuidle/poll_state.c | 14 +++++++++-----
> include/linux/cpuidle_haltpoll.h | 5 +++++
> 11 files changed, 41 insertions(+), 17 deletions(-)
>
Hi,
On Thu, Jan 25, 2024 at 3:40 PM Mihai Carabas <mihai.carabas@oraclecom> wrote:
>
> Hello,
>
> How can we move this patchset forward?
There have been some comments and a tag has been given.
Update the series (to address the comments and add the tag where
applicable) and resend.
Thanks!