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From: Andi Kleen <andi@firstfloor.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	Paul McKenney <paulmck@linux.vnet.ibm.com>,
	Waiman Long <Waiman.Long@hp.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
	Arnd Bergmann <arnd@arndb.de>,
	"linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>,
	the arch/x86 maintainers <x86@kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Michel Lespinasse <walken@google.com>,
	Rik van Riel <riel@redhat.com>,
	Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>,
	George Spelvin <linux@horizon.com>,
	Tim Chen <tim.c.chen@linux.intel.com>,
	Aswin Chandramouleeswaran <aswin@hp.com>,
	Scott J Norton <scott.norton@hp.com>
Subject: Re: [PATCH v7 1/4] qrwlock: A queue read/write lock implementation
Date: Wed, 18 Dec 2013 12:16:11 -0800	[thread overview]
Message-ID: <87zjnxlxtg.fsf@tassilo.jf.intel.com> (raw)
In-Reply-To: <20131218194615.GG16438@laptop.programming.kicks-ass.net> (Peter Zijlstra's message of "Wed, 18 Dec 2013 20:46:15 +0100")

Peter Zijlstra <peterz@infradead.org> writes:

> On Wed, Dec 18, 2013 at 11:38:29AM -0800, Andi Kleen wrote:
>> (maybe it would be time to get rid of the patchable LOCK though?)
>
> With the argument that Intel simply doesn't ship UP chips anymore, with
> the exception of quark which should probably run custom UP kernels due
> to size constraints anyway?

That, and:

- Anything with a single core only has very fast LOCK
- LOCK generally became much faster everywhere.
- The original reason was for single cpu VM guests, but even those
should increasingly have at least two VCPUs.

-Andi

-- 
ak@linux.intel.com -- Speaking for myself only

WARNING: multiple messages have this Message-ID (diff)
From: Andi Kleen <andi@firstfloor.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	Paul McKenney <paulmck@linux.vnet.ibm.com>,
	Waiman Long <Waiman.Long@hp.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
	Arnd Bergmann <arnd@arndb.de>,
	"linux-arch\@vger.kernel.org" <linux-arch@vger.kernel.org>,
	the arch/x86 maintainers <x86@kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Michel Lespinasse <walken@google.com>,
	Rik van Riel <riel@redhat.com>,
	Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>,
	George Spelvin <linux@horizon.com>,
	Tim Chen <tim.c.chen@linux.intel.com>,
	Aswin Chandramouleeswaran <aswin@hp.com>,
	Scott J Norton <scott.norton@hp.com>
Subject: Re: [PATCH v7 1/4] qrwlock: A queue read/write lock implementation
Date: Wed, 18 Dec 2013 12:16:11 -0800	[thread overview]
Message-ID: <87zjnxlxtg.fsf@tassilo.jf.intel.com> (raw)
In-Reply-To: <20131218194615.GG16438@laptop.programming.kicks-ass.net> (Peter Zijlstra's message of "Wed, 18 Dec 2013 20:46:15 +0100")

Peter Zijlstra <peterz@infradead.org> writes:

> On Wed, Dec 18, 2013 at 11:38:29AM -0800, Andi Kleen wrote:
>> (maybe it would be time to get rid of the patchable LOCK though?)
>
> With the argument that Intel simply doesn't ship UP chips anymore, with
> the exception of quark which should probably run custom UP kernels due
> to size constraints anyway?

That, and:

- Anything with a single core only has very fast LOCK
- LOCK generally became much faster everywhere.
- The original reason was for single cpu VM guests, but even those
should increasingly have at least two VCPUs.

-Andi

-- 
ak@linux.intel.com -- Speaking for myself only

  reply	other threads:[~2013-12-18 20:16 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-11-22 19:04 [PATCH v7 0/4] qrwlock: Introducing a queue read/write lock implementation Waiman Long
2013-11-22 19:04 ` [PATCH v7 1/4] qrwlock: A " Waiman Long
2013-11-22 19:14   ` Linus Torvalds
2013-11-22 20:35     ` Waiman Long
2013-11-22 21:14       ` Linus Torvalds
2013-12-17 19:21   ` Paul E. McKenney
2013-12-17 19:27     ` Linus Torvalds
2013-12-17 19:49       ` Paul E. McKenney
2013-12-18 18:51       ` Waiman Long
2013-12-18 19:38       ` Andi Kleen
2013-12-18 19:38         ` Andi Kleen
2013-12-18 19:42         ` Andi Kleen
2013-12-18 19:42           ` Andi Kleen
2013-12-18 19:46         ` Peter Zijlstra
2013-12-18 20:16           ` Andi Kleen [this message]
2013-12-18 20:16             ` Andi Kleen
2013-12-18 18:45     ` Waiman Long
2013-12-18 18:45       ` Waiman Long
2013-12-18 18:59       ` Paul E. McKenney
2013-12-18 19:16         ` Peter Zijlstra
2013-11-22 19:04 ` [PATCH v7 2/4] qrwlock x86: Enable x86 to use queue read/write lock Waiman Long
2013-12-17 19:22   ` Paul E. McKenney
2013-11-22 19:04 ` [PATCH v7 3/4] qrwlock: Use the mcs_spinlock helper functions for MCS queuing Waiman Long
2013-12-17 19:23   ` Paul E. McKenney
2013-11-22 19:04 ` [PATCH v7 4/4] qrwlock: Use smp_store_release() in write_unlock() Waiman Long
2013-12-17 19:24   ` Paul E. McKenney

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