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From: Peter Zijlstra <peterz@infradead.org>
To: Alex Kogan <alex.kogan@oracle.com>
Cc: linux-arch@vger.kernel.org, Hanjun Guo <guohanjun@huawei.com>,
	Arnd Bergmann <arnd@arndb.de>,
	dave.dice@oracle.com, Jan Glauber <jglauber@marvell.com>,
	x86@kernel.org, Will Deacon <will.deacon@arm.com>,
	linux@armlinux.org.uk, Steven Sistare <steven.sistare@oracle.com>,
	linux-kernel@vger.kernel.org, Ingo Molnar <mingo@redhat.com>,
	Borislav Petkov <bp@alien8.de>,
	hpa@zytor.com, Waiman Long <longman@redhat.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Daniel Jordan <daniel.m.jordan@oracle.com>,
	linux-arm-kernel <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v8 4/5] locking/qspinlock: Introduce starvation avoidance into CNA
Date: Fri, 24 Jan 2020 08:52:35 +0100	[thread overview]
Message-ID: <20200124075235.GX14914@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <3862F8A1-FF9B-40AD-A88E-2C0BA7AF6F58@oracle.com>

On Thu, Jan 23, 2020 at 04:33:54PM -0500, Alex Kogan wrote:
> Let me put this question to you. What do you think the number should be?

I think it would be very good to keep the inter-node latency below 1ms.

But to realize that we need data on the lock hold times. Specifically
for the heavily contended locks that make CNA worth it in the first
place.

I don't see that data, so I don't see how we can argue about this let
alone call something reasonable.

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  parent reply	other threads:[~2020-01-24  7:52 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-30 19:40 [PATCH v8 0/5] Add NUMA-awareness to qspinlock Alex Kogan
2019-12-30 19:40 ` [PATCH v8 1/5] locking/qspinlock: Rename mcs lock/unlock macros and make them more generic Alex Kogan
2019-12-30 19:40 ` [PATCH v8 2/5] locking/qspinlock: Refactor the qspinlock slow path Alex Kogan
2019-12-30 19:40 ` [PATCH v8 3/5] locking/qspinlock: Introduce CNA into the slow path of qspinlock Alex Kogan
2020-01-03 22:14   ` Waiman Long
2020-01-06 15:02     ` Alex Kogan
2020-01-21 13:48   ` Peter Zijlstra
2020-01-21 14:42   ` Peter Zijlstra
2019-12-30 19:40 ` [PATCH v8 4/5] locking/qspinlock: Introduce starvation avoidance into CNA Alex Kogan
2020-01-06 15:33   ` Waiman Long
2020-01-21 13:29   ` Peter Zijlstra
2020-01-21 13:50     ` Peter Zijlstra
2020-01-21 21:19       ` Daniel Bristot de Oliveira
2020-01-21 15:45     ` Waiman Long
     [not found]       ` <3862F8A1-FF9B-40AD-A88E-2C0BA7AF6F58@oracle.com>
2020-01-24  7:52         ` Peter Zijlstra [this message]
2020-01-24 14:42           ` Waiman Long
2020-01-24 15:13             ` Peter Zijlstra
2020-01-24 15:19             ` Waiman Long
     [not found]               ` <8D3AFB47-B595-418C-9568-08780DDC58FF@oracle.com>
     [not found]                 ` <714892cd-d96f-4d41-ae8b-d7b7642a6e3c@redhat.com>
2020-01-25 11:16                   ` Peter Zijlstra
     [not found]                   ` <1669BFDE-A1A5-4ED8-B586-035460BBF68A@oracle.com>
     [not found]                     ` <45660873-731a-a810-8c57-1a5a19d266b4@redhat.com>
2020-01-24 18:51                       ` Waiman Long
2020-01-25 11:20                         ` Peter Zijlstra
2020-01-25 19:57                         ` Waiman Long
     [not found]                       ` <693E6287-E37C-4C5D-BE33-B3D813BE505D@oracle.com>
2020-01-24 21:12                         ` Waiman Long
2020-01-24 21:27                           ` Alex Kogan
2020-01-25  0:38                             ` Waiman Long
2020-01-25 11:19                     ` Peter Zijlstra
2020-01-30 22:05                       ` Alex Kogan
2020-02-03 13:45                         ` Peter Zijlstra
2020-02-03 14:59                           ` Waiman Long
2020-02-03 15:28                             ` Peter Zijlstra
2020-02-03 15:47                               ` Waiman Long
     [not found]                                 ` <83762715-F68C-42DF-9B41-C4C48DF6762F@oracle.com>
2020-02-04 17:27                                   ` Peter Zijlstra
2020-02-04 17:39                                     ` Waiman Long
2020-02-04 17:53                                       ` Alex Kogan
2019-12-30 19:40 ` [PATCH v8 5/5] locking/qspinlock: Introduce the shuffle reduction optimization " Alex Kogan
2020-01-22  9:56   ` Peter Zijlstra
2020-01-06 15:48 ` [PATCH v8 0/5] Add NUMA-awareness to qspinlock Waiman Long
2020-01-08  5:09 ` Shijith Thotton
2020-01-21  9:21   ` Shijith Thotton

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