From: Peter Zijlstra <peterz@infradead.org>
To: Alex Kogan <alex.kogan@oracle.com>
Cc: linux@armlinux.org.uk, mingo@redhat.com, will.deacon@arm.com,
arnd@arndb.de, longman@redhat.com, linux-arch@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, tglx@linutronix.de, bp@alien8.de,
hpa@zytor.com, x86@kernel.org, guohanjun@huawei.com,
jglauber@marvell.com, steven.sistare@oracle.com,
daniel.m.jordan@oracle.com, dave.dice@oracle.com
Subject: Re: [PATCH v8 5/5] locking/qspinlock: Introduce the shuffle reduction optimization into CNA
Date: Wed, 22 Jan 2020 10:56:22 +0100 [thread overview]
Message-ID: <20200122095622.GS14914@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20191230194042.67789-6-alex.kogan@oracle.com>
On Mon, Dec 30, 2019 at 02:40:42PM -0500, Alex Kogan wrote:
> @@ -251,8 +281,11 @@ __always_inline u32 cna_pre_scan(struct qspinlock *lock,
> struct cna_node *cn = (struct cna_node *)node;
>
> cn->pre_scan_result =
> - cn->intra_count == intra_node_handoff_threshold ?
> - FLUSH_SECONDARY_QUEUE : cna_scan_main_queue(node, node);
> + (node->locked <= 1 && probably(SHUFFLE_REDUCTION_PROB_ARG)) ?
> + PASS_LOCK_IMMEDIATELY :
> + cn->intra_count == intra_node_handoff_threshold ?
> + FLUSH_SECONDARY_QUEUE :
> + cna_scan_main_queue(node, node);
>
> return 0;
> }
Let me just, once again, remind people that the Linux Kernel is not part
of the Obfuscated C code contest.
> Reviewed-by: Steve Sistare <steven.sistare@oracle.com>
Seriously, in what universe is that actually readable code? Steve quick,
say what it does.
next prev parent reply other threads:[~2020-01-22 9:56 UTC|newest]
Thread overview: 72+ 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 ` 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 ` 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 ` Alex Kogan
2019-12-30 19:40 ` [PATCH v8 3/5] locking/qspinlock: Introduce CNA into the slow path of qspinlock Alex Kogan
2019-12-30 19:40 ` Alex Kogan
2020-01-03 22:14 ` Waiman Long
2020-01-03 22:14 ` Waiman Long
2020-01-06 15:02 ` Alex Kogan
2020-01-06 15:02 ` Alex Kogan
2020-01-21 13:48 ` Peter Zijlstra
2020-01-21 13:48 ` Peter Zijlstra
2020-01-21 14:42 ` 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
2019-12-30 19:40 ` Alex Kogan
2020-01-06 15:33 ` Waiman Long
2020-01-06 15:33 ` Waiman Long
2020-01-21 13:29 ` Peter Zijlstra
2020-01-21 13:29 ` Peter Zijlstra
2020-01-21 13:50 ` Peter Zijlstra
2020-01-21 13:50 ` Peter Zijlstra
2020-01-21 21:19 ` Daniel Bristot de Oliveira
2020-01-21 21:19 ` Daniel Bristot de Oliveira
2020-01-21 15:45 ` Waiman Long
2020-01-21 15:45 ` Waiman Long
[not found] ` <3862F8A1-FF9B-40AD-A88E-2C0BA7AF6F58@oracle.com>
2020-01-24 7:52 ` Peter Zijlstra
2020-01-24 7:52 ` Peter Zijlstra
2020-01-24 14:42 ` Waiman Long
2020-01-24 15:13 ` Peter Zijlstra
2020-01-24 15:13 ` Peter Zijlstra
2020-01-24 15:19 ` Waiman Long
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
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
2020-01-24 18:51 ` Waiman Long
2020-01-25 11:20 ` Peter Zijlstra
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 21:12 ` Waiman Long
2020-01-24 21:27 ` Alex Kogan
2020-01-25 0:38 ` Waiman Long
2020-01-25 0:38 ` Waiman Long
2020-01-25 11:19 ` Peter Zijlstra
2020-01-25 11:19 ` Peter Zijlstra
2020-01-30 22:05 ` Alex Kogan
2020-02-03 13:45 ` Peter Zijlstra
2020-02-03 13:45 ` Peter Zijlstra
2020-02-03 14:59 ` Waiman Long
2020-02-03 14:59 ` Waiman Long
2020-02-03 15:28 ` Peter Zijlstra
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 17:27 ` Peter Zijlstra
2020-02-04 17:39 ` Waiman Long
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
2019-12-30 19:40 ` Alex Kogan
2020-01-22 9:56 ` Peter Zijlstra [this message]
2020-01-22 9:56 ` Peter Zijlstra
2020-01-06 15:48 ` [PATCH v8 0/5] Add NUMA-awareness to qspinlock Waiman Long
2020-01-06 15:48 ` Waiman Long
2020-01-08 5:09 ` Shijith Thotton
2020-01-08 5:09 ` Shijith Thotton
2020-01-21 9:21 ` Shijith Thotton
2020-01-21 9:21 ` Shijith Thotton
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