From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
To: paulmck@kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
Peter Zijlstra <peterz@infradead.org>,
linux-kernel@vger.kernel.org, Nicholas Piggin <npiggin@gmail.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Will Deacon <will@kernel.org>, Boqun Feng <boqun.feng@gmail.com>,
Alan Stern <stern@rowland.harvard.edu>,
John Stultz <jstultz@google.com>,
Neeraj Upadhyay <Neeraj.Upadhyay@amd.com>,
Frederic Weisbecker <frederic@kernel.org>,
Joel Fernandes <joel@joelfernandes.org>,
Josh Triplett <josh@joshtriplett.org>,
Uladzislau Rezki <urezki@gmail.com>,
Steven Rostedt <rostedt@goodmis.org>,
Lai Jiangshan <jiangshanlai@gmail.com>,
Zqiang <qiang.zhang1211@gmail.com>,
Ingo Molnar <mingo@redhat.com>, Waiman Long <longman@redhat.com>,
Mark Rutland <mark.rutland@arm.com>,
Thomas Gleixner <tglx@linutronix.de>,
Vlastimil Babka <vbabka@suse.cz>,
maged.michael@gmail.com, Mateusz Guzik <mjguzik@gmail.com>,
Jonas Oberhauser <jonas.oberhauser@huaweicloud.com>,
rcu@vger.kernel.org, linux-mm@kvack.org, lkmm@lists.linux.dev
Subject: Re: [RFC PATCH 0/4] sched+mm: Track lazy active mm existence with hazard pointers
Date: Wed, 2 Oct 2024 11:26:27 -0400 [thread overview]
Message-ID: <d412fa7e-6348-4e51-89e8-4c740184cb2f@efficios.com> (raw)
In-Reply-To: <cfcf9c05-c639-4757-a3ac-6504d154cdfe@paulmck-laptop>
On 2024-10-02 16:09, Paul E. McKenney wrote:
> On Tue, Oct 01, 2024 at 09:02:01PM -0400, Mathieu Desnoyers wrote:
>> Hazard pointers appear to be a good fit for replacing refcount based lazy
>> active mm tracking.
>>
>> Highlight:
>>
>> will-it-scale context_switch1_threads
>>
>> nr threads (-t) speedup
>> 24 +3%
>> 48 +12%
>> 96 +21%
>> 192 +28%
>
> Impressive!!!
>
> I have to ask... Any data for smaller numbers of CPUs?
Sure, but they are far less exciting ;-)
nr threads (-t) speedup
1 -0.2%
2 +0.4%
3 +0.2%
6 +0.6%
12 +0.8%
24 +3%
48 +12%
96 +21%
192 +28%
384 +4%
768 -0.6%
Thanks,
Mathieu
>
> Thanx, Paul
>
>> I'm curious to see what the build bots have to say about this.
>>
>> This series applies on top of v6.11.1.
>>
>> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
>> Cc: Nicholas Piggin <npiggin@gmail.com>
>> Cc: Michael Ellerman <mpe@ellerman.id.au>
>> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
>> Cc: "Paul E. McKenney" <paulmck@kernel.org>
>> Cc: Will Deacon <will@kernel.org>
>> Cc: Boqun Feng <boqun.feng@gmail.com>
>> Cc: Alan Stern <stern@rowland.harvard.edu>
>> Cc: John Stultz <jstultz@google.com>
>> Cc: Neeraj Upadhyay <Neeraj.Upadhyay@amd.com>
>> Cc: Boqun Feng <boqun.feng@gmail.com>
>> Cc: Frederic Weisbecker <frederic@kernel.org>
>> Cc: Joel Fernandes <joel@joelfernandes.org>
>> Cc: Josh Triplett <josh@joshtriplett.org>
>> Cc: Uladzislau Rezki <urezki@gmail.com>
>> Cc: Steven Rostedt <rostedt@goodmis.org>
>> Cc: Lai Jiangshan <jiangshanlai@gmail.com>
>> Cc: Zqiang <qiang.zhang1211@gmail.com>
>> Cc: Ingo Molnar <mingo@redhat.com>
>> Cc: Waiman Long <longman@redhat.com>
>> Cc: Mark Rutland <mark.rutland@arm.com>
>> Cc: Thomas Gleixner <tglx@linutronix.de>
>> Cc: Vlastimil Babka <vbabka@suse.cz>
>> Cc: maged.michael@gmail.com
>> Cc: Mateusz Guzik <mjguzik@gmail.com>
>> Cc: Jonas Oberhauser <jonas.oberhauser@huaweicloud.com>
>> Cc: rcu@vger.kernel.org
>> Cc: linux-mm@kvack.org
>> Cc: lkmm@lists.linux.dev
>>
>> Mathieu Desnoyers (4):
>> compiler.h: Introduce ptr_eq() to preserve address dependency
>> Documentation: RCU: Refer to ptr_eq()
>> hp: Implement Hazard Pointers
>> sched+mm: Use hazard pointers to track lazy active mm existence
>>
>> Documentation/RCU/rcu_dereference.rst | 38 ++++++-
>> Documentation/mm/active_mm.rst | 9 +-
>> arch/Kconfig | 32 ------
>> arch/powerpc/Kconfig | 1 -
>> arch/powerpc/mm/book3s64/radix_tlb.c | 23 +---
>> include/linux/compiler.h | 63 +++++++++++
>> include/linux/hp.h | 154 ++++++++++++++++++++++++++
>> include/linux/mm_types.h | 3 -
>> include/linux/sched/mm.h | 71 +++++-------
>> kernel/Makefile | 2 +-
>> kernel/exit.c | 4 +-
>> kernel/fork.c | 47 ++------
>> kernel/hp.c | 46 ++++++++
>> kernel/sched/sched.h | 8 +-
>> lib/Kconfig.debug | 10 --
>> 15 files changed, 346 insertions(+), 165 deletions(-)
>> create mode 100644 include/linux/hp.h
>> create mode 100644 kernel/hp.c
>>
>> --
>> 2.39.2
--
Mathieu Desnoyers
EfficiOS Inc.
https://www.efficios.com
next prev parent reply other threads:[~2024-10-02 15:28 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-10-02 1:02 [RFC PATCH 0/4] sched+mm: Track lazy active mm existence with hazard pointers Mathieu Desnoyers
2024-10-02 1:02 ` [RFC PATCH 1/4] compiler.h: Introduce ptr_eq() to preserve address dependency Mathieu Desnoyers
2024-10-03 0:08 ` Joel Fernandes
2024-10-03 14:19 ` Mathieu Desnoyers
2024-10-03 22:09 ` Joel Fernandes
2024-10-02 1:02 ` [RFC PATCH 2/4] Documentation: RCU: Refer to ptr_eq() Mathieu Desnoyers
2024-10-02 1:02 ` [RFC PATCH 3/4] hp: Implement Hazard Pointers Mathieu Desnoyers
2024-10-03 0:24 ` Boqun Feng
2024-10-03 13:30 ` Mathieu Desnoyers
2024-10-07 13:47 ` Boqun Feng
2024-10-07 14:52 ` Mathieu Desnoyers
2024-10-02 1:02 ` [RFC PATCH 4/4] sched+mm: Use hazard pointers to track lazy active mm existence Mathieu Desnoyers
2024-10-02 14:09 ` [RFC PATCH 0/4] sched+mm: Track lazy active mm existence with hazard pointers Paul E. McKenney
2024-10-02 15:26 ` Mathieu Desnoyers [this message]
2024-10-02 15:33 ` Matthew Wilcox
2024-10-02 15:36 ` Mathieu Desnoyers
2024-10-02 15:53 ` Mathieu Desnoyers
2024-10-02 15:58 ` Jens Axboe
2024-10-02 16:02 ` Mathieu Desnoyers
2024-10-02 16:14 ` Jens Axboe
2024-10-02 17:39 ` Linus Torvalds
2024-10-05 16:15 ` Peter Zijlstra
2024-10-05 16:56 ` Linus Torvalds
2024-10-07 7:06 ` Peter Zijlstra
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