From: "Nicholas Piggin" <npiggin@gmail.com>
To: "Jordan Niethe" <jniethe5@gmail.com>, <linuxppc-dev@lists.ozlabs.org>
Subject: Re: [PATCH 14/17] powerpc/qspinlock: use spin_begin/end API
Date: Thu, 10 Nov 2022 21:36:00 +1000 [thread overview]
Message-ID: <CO8L2EZR2P0D.1G72IZFI1KNAQ@bobo> (raw)
In-Reply-To: <b0a117995bb311dff161c475f7ba76709252c995.camel@gmail.com>
On Thu Nov 10, 2022 at 10:43 AM AEST, Jordan Niethe wrote:
> On Thu, 2022-07-28 at 16:31 +1000, Nicholas Piggin wrote:
> [resend as utf-8, not utf-7]
> > Use the spin_begin/spin_cpu_relax/spin_end APIs in qspinlock, which helps
> > to prevent threads issuing a lot of expensive priority nops which may not
> > have much effect due to immediately executing low then medium priority.
>
> Just a general comment regarding the spin_{begin,end} API, more complicated
> than something like
>
> spin_begin()
> for(;;)
> spin_cpu_relax()
> spin_end()
>
> it becomes difficult to keep track of. Unfortunately, I don't have any good
> suggestions how to improve it. Hopefully with P10s wait instruction we can
> maybe try and move away from this.
>
> It might be useful to comment the functions pre and post conditions regarding
> expectations about spin_begin() and spin_end().
Yep, added some small comments.
Thanks,
Nick
next prev parent reply other threads:[~2022-11-10 11:37 UTC|newest]
Thread overview: 78+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-28 6:31 [PATCH 00/17] powerpc: alternate queued spinlock implementation Nicholas Piggin
2022-07-28 6:31 ` [PATCH 01/17] powerpc/qspinlock: powerpc qspinlock implementation Nicholas Piggin
2022-08-10 1:52 ` Jordan NIethe
2022-08-10 6:48 ` Christophe Leroy
2022-11-10 0:35 ` Jordan Niethe
2022-11-10 6:37 ` Christophe Leroy
2022-11-10 11:44 ` Nicholas Piggin
2022-11-10 9:09 ` Nicholas Piggin
2022-07-28 6:31 ` [PATCH 1a/17] powerpc/qspinlock: Prepare qspinlock code Nicholas Piggin
2022-07-28 6:31 ` [PATCH 02/17] powerpc/qspinlock: add mcs queueing for contended waiters Nicholas Piggin
2022-08-10 2:28 ` Jordan NIethe
2022-11-10 0:36 ` Jordan Niethe
2022-11-10 9:21 ` Nicholas Piggin
2022-07-28 6:31 ` [PATCH 03/17] powerpc/qspinlock: use a half-word store to unlock to avoid larx/stcx Nicholas Piggin
2022-08-10 3:28 ` Jordan Niethe
2022-11-10 0:39 ` Jordan Niethe
2022-11-10 9:25 ` Nicholas Piggin
2022-07-28 6:31 ` [PATCH 04/17] powerpc/qspinlock: convert atomic operations to assembly Nicholas Piggin
2022-08-10 3:54 ` Jordan Niethe
2022-11-10 0:39 ` Jordan Niethe
2022-11-10 8:36 ` Christophe Leroy
2022-11-10 11:48 ` Nicholas Piggin
2022-11-10 9:40 ` Nicholas Piggin
2022-07-28 6:31 ` [PATCH 05/17] powerpc/qspinlock: allow new waiters to steal the lock before queueing Nicholas Piggin
2022-08-10 4:31 ` Jordan Niethe
2022-11-10 0:40 ` Jordan Niethe
2022-11-10 10:54 ` Nicholas Piggin
2022-07-28 6:31 ` [PATCH 06/17] powerpc/qspinlock: theft prevention to control latency Nicholas Piggin
2022-08-10 5:51 ` Jordan Niethe
2022-11-10 0:40 ` Jordan Niethe
2022-11-10 10:57 ` Nicholas Piggin
2022-07-28 6:31 ` [PATCH 07/17] powerpc/qspinlock: store owner CPU in lock word Nicholas Piggin
2022-08-12 0:50 ` Jordan Niethe
2022-11-10 0:40 ` Jordan Niethe
2022-11-10 10:59 ` Nicholas Piggin
2022-07-28 6:31 ` [PATCH 08/17] powerpc/qspinlock: paravirt yield to lock owner Nicholas Piggin
2022-08-12 2:01 ` Jordan Niethe
2022-11-10 0:41 ` Jordan Niethe
2022-11-10 11:13 ` Nicholas Piggin
2022-07-28 6:31 ` [PATCH 09/17] powerpc/qspinlock: implement option to yield to previous node Nicholas Piggin
2022-08-12 2:07 ` Jordan Niethe
2022-11-10 0:41 ` Jordan Niethe
2022-11-10 11:14 ` Nicholas Piggin
2022-07-28 6:31 ` [PATCH 10/17] powerpc/qspinlock: allow stealing when head of queue yields Nicholas Piggin
2022-08-12 4:06 ` Jordan Niethe
2022-11-10 0:42 ` Jordan Niethe
2022-11-10 11:22 ` Nicholas Piggin
2022-07-28 6:31 ` [PATCH 11/17] powerpc/qspinlock: allow propagation of yield CPU down the queue Nicholas Piggin
2022-08-12 4:17 ` Jordan Niethe
2022-10-06 17:27 ` Laurent Dufour
2022-11-10 0:42 ` Jordan Niethe
2022-11-10 11:25 ` Nicholas Piggin
2022-07-28 6:31 ` [PATCH 12/17] powerpc/qspinlock: add ability to prod new queue head CPU Nicholas Piggin
2022-08-12 4:22 ` Jordan Niethe
2022-11-10 0:42 ` Jordan Niethe
2022-11-10 11:32 ` Nicholas Piggin
2022-07-28 6:31 ` [PATCH 13/17] powerpc/qspinlock: trylock and initial lock attempt may steal Nicholas Piggin
2022-08-12 4:32 ` Jordan Niethe
2022-11-10 0:43 ` Jordan Niethe
2022-11-10 11:35 ` Nicholas Piggin
2022-07-28 6:31 ` [PATCH 14/17] powerpc/qspinlock: use spin_begin/end API Nicholas Piggin
2022-08-12 4:36 ` Jordan Niethe
2022-11-10 0:43 ` Jordan Niethe
2022-11-10 11:36 ` Nicholas Piggin [this message]
2022-07-28 6:31 ` [PATCH 15/17] powerpc/qspinlock: reduce remote node steal spins Nicholas Piggin
2022-08-12 4:43 ` Jordan Niethe
2022-11-10 0:43 ` Jordan Niethe
2022-11-10 11:37 ` Nicholas Piggin
2022-07-28 6:31 ` [PATCH 16/17] powerpc/qspinlock: allow indefinite spinning on a preempted owner Nicholas Piggin
2022-08-12 4:49 ` Jordan Niethe
2022-09-22 15:02 ` Laurent Dufour
2022-09-23 8:16 ` Nicholas Piggin
2022-11-10 0:44 ` Jordan Niethe
2022-11-10 11:38 ` Nicholas Piggin
2022-07-28 6:31 ` [PATCH 17/17] powerpc/qspinlock: provide accounting and options for sleepy locks Nicholas Piggin
2022-08-15 1:11 ` Jordan Niethe
2022-11-10 0:44 ` Jordan Niethe
2022-11-10 11:41 ` Nicholas Piggin
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