From: Peter Zijlstra <peterz@infradead.org>
To: Torsten Duwe <duwe@lst.de>
Cc: Tom Musta <tommusta@gmail.com>,
linux-kernel@vger.kernel.org, Paul Mackerras <paulus@samba.org>,
Anton Blanchard <anton@samba.org>,
Scott Wood <scottwood@freescale.com>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
linuxppc-dev@lists.ozlabs.org, Ingo Molnar <mingo@kernel.org>
Subject: Re: [PATCH] Convert powerpc simple spinlocks into ticket locks
Date: Fri, 7 Feb 2014 11:45:30 +0100 [thread overview]
Message-ID: <20140207104530.GG5126@laptop.programming.kicks-ass.net> (raw)
In-Reply-To: <20140207103139.GP5002@laptop.programming.kicks-ass.net>
On Fri, Feb 07, 2014 at 11:31:39AM +0100, Peter Zijlstra wrote:
> Anyway, what might work is something like (please forgive my ppc asm, I
> can barely read the thing, I've never before attempted writing it):
>
> lock:
> 1: lharx %0, 0, &head
> mov %1, %0
> addic %0, %0, 1
> stwcd %0, 0, &head
> bne- 1b
> 2: lhax %0, 0, &tail
That might need to be lhz too, I'm confused on all the load variants.
> lwsync
> cmp 0, %0, %0
cmp 0, %0, %1
So we compare the &tail load to the xadd return %1 above.
> bne- 2b
>
>
> unlock:
> lhz %0, 0, &tail
> addic %0, %0, 1
> lwsync
> sth %0, 0, &tail
>
WARNING: multiple messages have this Message-ID (diff)
From: Peter Zijlstra <peterz@infradead.org>
To: Torsten Duwe <duwe@lst.de>
Cc: Scott Wood <scottwood@freescale.com>,
linux-kernel@vger.kernel.org, Paul Mackerras <paulus@samba.org>,
Anton Blanchard <anton@samba.org>, Tom Musta <tommusta@gmail.com>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
linuxppc-dev@lists.ozlabs.org, Ingo Molnar <mingo@kernel.org>
Subject: Re: [PATCH] Convert powerpc simple spinlocks into ticket locks
Date: Fri, 7 Feb 2014 11:45:30 +0100 [thread overview]
Message-ID: <20140207104530.GG5126@laptop.programming.kicks-ass.net> (raw)
In-Reply-To: <20140207103139.GP5002@laptop.programming.kicks-ass.net>
On Fri, Feb 07, 2014 at 11:31:39AM +0100, Peter Zijlstra wrote:
> Anyway, what might work is something like (please forgive my ppc asm, I
> can barely read the thing, I've never before attempted writing it):
>
> lock:
> 1: lharx %0, 0, &head
> mov %1, %0
> addic %0, %0, 1
> stwcd %0, 0, &head
> bne- 1b
> 2: lhax %0, 0, &tail
That might need to be lhz too, I'm confused on all the load variants.
> lwsync
> cmp 0, %0, %0
cmp 0, %0, %1
So we compare the &tail load to the xadd return %1 above.
> bne- 2b
>
>
> unlock:
> lhz %0, 0, &tail
> addic %0, %0, 1
> lwsync
> sth %0, 0, &tail
>
next prev parent reply other threads:[~2014-02-07 10:45 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-06 10:37 [PATCH] Convert powerpc simple spinlocks into ticket locks Torsten Duwe
2014-02-06 10:37 ` Torsten Duwe
2014-02-06 15:53 ` Benjamin Herrenschmidt
2014-02-06 15:53 ` Benjamin Herrenschmidt
2014-02-06 16:38 ` Peter Zijlstra
2014-02-06 16:38 ` Peter Zijlstra
2014-02-06 17:37 ` Torsten Duwe
2014-02-06 17:37 ` Torsten Duwe
2014-02-06 18:08 ` Peter Zijlstra
2014-02-06 18:08 ` Peter Zijlstra
2014-02-06 19:28 ` Tom Musta
2014-02-10 2:54 ` Benjamin Herrenschmidt
2014-02-10 2:54 ` Benjamin Herrenschmidt
2014-02-07 8:24 ` Torsten Duwe
2014-02-07 8:24 ` Torsten Duwe
2014-02-06 20:19 ` Scott Wood
2014-02-06 20:19 ` Scott Wood
2014-02-07 9:02 ` Torsten Duwe
2014-02-07 9:02 ` Torsten Duwe
2014-02-07 10:31 ` Peter Zijlstra
2014-02-07 10:31 ` Peter Zijlstra
2014-02-07 10:36 ` Peter Zijlstra
2014-02-07 10:36 ` Peter Zijlstra
2014-02-07 10:45 ` Peter Zijlstra [this message]
2014-02-07 10:45 ` Peter Zijlstra
2014-02-07 11:49 ` Torsten Duwe
2014-02-07 11:49 ` Torsten Duwe
2014-02-07 12:28 ` Peter Zijlstra
2014-02-07 12:28 ` Peter Zijlstra
2014-02-07 15:18 ` Peter Zijlstra
2014-02-07 15:18 ` Peter Zijlstra
2014-02-07 15:43 ` Peter Zijlstra
2014-02-07 15:43 ` Peter Zijlstra
2014-02-07 17:08 ` Torsten Duwe
2014-02-07 17:08 ` Torsten Duwe
2014-02-07 17:19 ` Peter Zijlstra
2014-02-07 17:19 ` Peter Zijlstra
2014-02-07 15:51 ` Kumar Gala
2014-02-07 15:51 ` Kumar Gala
2014-02-07 16:10 ` Peter Zijlstra
2014-02-07 16:10 ` Peter Zijlstra
2014-02-10 3:05 ` Benjamin Herrenschmidt
2014-02-10 3:05 ` Benjamin Herrenschmidt
2014-02-10 3:02 ` Benjamin Herrenschmidt
2014-02-10 3:02 ` Benjamin Herrenschmidt
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20140207104530.GG5126@laptop.programming.kicks-ass.net \
--to=peterz@infradead.org \
--cc=anton@samba.org \
--cc=duwe@lst.de \
--cc=linux-kernel@vger.kernel.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=mingo@kernel.org \
--cc=paulmck@linux.vnet.ibm.com \
--cc=paulus@samba.org \
--cc=scottwood@freescale.com \
--cc=tommusta@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.