From: Michael Ellerman <mpe@ellerman.id.au>
To: linuxppc-dev@lists.ozlabs.org
Cc: Nicholas Piggin <npiggin@gmail.com>,
Will Deacon <will@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Boqun Feng <boqun.feng@gmail.com>, Ingo Molnar <mingo@redhat.com>,
Waiman Long <longman@redhat.com>,
Anton Blanchard <anton@ozlabs.org>,
linux-kernel@vger.kernel.org,
virtualization@lists.linux-foundation.org,
kvm-ppc@vger.kernel.org, linux-arch@vger.kernel.org
Subject: Re: [PATCH v3 4/6] powerpc/64s: implement queued spinlocks and rwlocks
Date: Thu, 09 Jul 2020 20:20:25 +1000 [thread overview]
Message-ID: <877dvdvvkm.fsf@mpe.ellerman.id.au> (raw)
In-Reply-To: <20200706043540.1563616-5-npiggin@gmail.com>
Nicholas Piggin <npiggin@gmail.com> writes:
> These have shown significantly improved performance and fairness when
> spinlock contention is moderate to high on very large systems.
>
> [ Numbers hopefully forthcoming after more testing, but initial
> results look good ]
Would be good to have something here, even if it's preliminary.
> Thanks to the fast path, single threaded performance is not noticably
> hurt.
>
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
> ---
> arch/powerpc/Kconfig | 13 ++++++++++++
> arch/powerpc/include/asm/Kbuild | 2 ++
> arch/powerpc/include/asm/qspinlock.h | 25 +++++++++++++++++++++++
> arch/powerpc/include/asm/spinlock.h | 5 +++++
> arch/powerpc/include/asm/spinlock_types.h | 5 +++++
> arch/powerpc/lib/Makefile | 3 +++
> include/asm-generic/qspinlock.h | 2 ++
Who's ack do we need for that part?
> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> index 24ac85c868db..17663ea57697 100644
> --- a/arch/powerpc/Kconfig
> +++ b/arch/powerpc/Kconfig
> @@ -492,6 +494,17 @@ config HOTPLUG_CPU
>
> Say N if you are unsure.
>
> +config PPC_QUEUED_SPINLOCKS
> + bool "Queued spinlocks"
> + depends on SMP
> + default "y" if PPC_BOOK3S_64
Not sure about default y? At least until we've got a better idea of the
perf impact on a range of small/big new/old systems.
> + help
> + Say Y here to use to use queued spinlocks which are more complex
> + but give better salability and fairness on large SMP and NUMA
> + systems.
> +
> + If unsure, say "Y" if you have lots of cores, otherwise "N".
Would be nice if we could give a range for "lots".
> diff --git a/arch/powerpc/include/asm/Kbuild b/arch/powerpc/include/asm/Kbuild
> index dadbcf3a0b1e..1dd8b6adff5e 100644
> --- a/arch/powerpc/include/asm/Kbuild
> +++ b/arch/powerpc/include/asm/Kbuild
> @@ -6,5 +6,7 @@ generated-y += syscall_table_spu.h
> generic-y += export.h
> generic-y += local64.h
> generic-y += mcs_spinlock.h
> +generic-y += qrwlock.h
> +generic-y += qspinlock.h
The 2nd line spits a warning about a redundant entry. I think you want
to just drop it.
cheers
next prev parent reply other threads:[~2020-07-09 10:20 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-06 4:35 [PATCH v3 0/6] powerpc: queued spinlocks and rwlocks Nicholas Piggin
2020-07-06 4:35 ` [PATCH v3 1/6] powerpc/powernv: must include hvcall.h to get PAPR defines Nicholas Piggin
2020-07-09 10:05 ` Michael Ellerman
2020-07-06 4:35 ` [PATCH v3 2/6] powerpc/pseries: move some PAPR paravirt functions to their own file Nicholas Piggin
2020-07-09 10:11 ` Michael Ellerman
2020-07-06 4:35 ` [PATCH v3 3/6] powerpc: move spinlock implementation to simple_spinlock Nicholas Piggin
2020-07-09 10:15 ` Michael Ellerman
2020-07-06 4:35 ` [PATCH v3 4/6] powerpc/64s: implement queued spinlocks and rwlocks Nicholas Piggin
2020-07-09 10:20 ` Michael Ellerman [this message]
2020-07-09 10:33 ` Peter Zijlstra
2020-07-23 14:37 ` Michal Suchánek
2020-07-06 4:35 ` [PATCH v3 5/6] powerpc/pseries: implement paravirt qspinlocks for SPLPAR Nicholas Piggin
2020-07-09 10:53 ` Michael Ellerman
2020-07-09 11:03 ` Peter Zijlstra
2020-07-09 16:06 ` Waiman Long
2020-07-23 14:00 ` Peter Zijlstra
2020-07-23 18:32 ` Waiman Long
2020-07-23 18:47 ` peterz
2020-07-23 19:04 ` Waiman Long
2020-07-23 19:58 ` peterz
2020-07-23 20:30 ` Segher Boessenkool
2020-07-23 21:58 ` Waiman Long
2020-07-23 14:09 ` Nicholas Piggin
2020-07-06 4:35 ` [PATCH v3 6/6] powerpc/qspinlock: optimised atomic_try_cmpxchg_lock that adds the lock hint Nicholas Piggin
2020-07-06 18:39 ` [PATCH v3 0/6] powerpc: queued spinlocks and rwlocks Waiman Long
2020-07-07 5:57 ` Nicholas Piggin
2020-07-08 3:33 ` Waiman Long
2020-07-08 5:10 ` Nicholas Piggin
2020-07-08 23:50 ` Waiman Long
2020-07-08 23:58 ` Waiman Long
2020-07-08 8:32 ` Peter Zijlstra
2020-07-08 23:53 ` Waiman Long
2020-07-08 8:41 ` Peter Zijlstra
2020-07-08 23:54 ` Waiman Long
2020-07-09 8:31 ` Peter Zijlstra
2020-07-21 11:20 ` Nicholas Piggin
2020-07-21 11:08 ` Nicholas Piggin
2020-07-21 14:36 ` Waiman Long
2020-07-23 13:30 ` Nicholas Piggin
2020-07-23 14:29 ` Waiman Long
2020-07-23 16:12 ` Nicholas Piggin
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