From: Peter Zijlstra <peterz@infradead.org>
To: Waiman Long <waiman.long@hp.com>
Cc: linux-arch@vger.kernel.org,
Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>,
Oleg Nesterov <oleg@redhat.com>, Gleb Natapov <gleb@redhat.com>,
kvm@vger.kernel.org, Scott J Norton <scott.norton@hp.com>,
x86@kernel.org, Paolo Bonzini <paolo.bonzini@gmail.com>,
linux-kernel@vger.kernel.org,
virtualization@lists.linux-foundation.org,
Ingo Molnar <mingo@redhat.com>, Chegu Vinod <chegu_vinod@hp.com>,
David Vrabel <david.vrabel@citrix.com>,
"H. Peter Anvin" <hpa@zytor.com>,
xen-devel@lists.xenproject.org,
Thomas Gleixner <tglx@linutronix.de>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>
Subject: Re: [PATCH v11 09/16] qspinlock, x86: Allow unfair spinlock in a virtual guest
Date: Sun, 15 Jun 2014 15:14:16 +0200 [thread overview]
Message-ID: <20140615131416.GI11371__46150.2527971335$1402838158$gmane$org@laptop.programming.kicks-ass.net> (raw)
In-Reply-To: <539A16CC.6040104@hp.com>
On Thu, Jun 12, 2014 at 05:08:28PM -0400, Waiman Long wrote:
> >Native performance is king, try your very utmost bestest to preserve
> >that, paravirt is a distant second and nobody sane should care about the
> >virt case at all.
>
> The patch won't affect native performance unless the kernel is built with
> VIRT_UNFAIR_LOCKS selected. The same is also true when PARAVIRT_SPINLOCKS is
> selected. There is no way around that.
VIRT_UNFAIR_LOCKS is an impossible switch to have; a distro cannot make
the right choice.
> I do agree that I may over-engineer on this patch,
Simple things first, then add complexity.
next prev parent reply other threads:[~2014-06-15 13:14 UTC|newest]
Thread overview: 102+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-30 15:43 [PATCH v11 00/16] qspinlock: a 4-byte queue spinlock with PV support Waiman Long
2014-05-30 15:43 ` [PATCH v11 01/16] qspinlock: A simple generic 4-byte queue spinlock Waiman Long
2014-05-30 15:43 ` Waiman Long
2014-05-30 15:43 ` Waiman Long
2014-05-30 15:43 ` Waiman Long
2014-05-30 15:43 ` Waiman Long
2014-05-30 15:43 ` [PATCH v11 02/16] qspinlock, x86: Enable x86-64 to use " Waiman Long
2014-05-30 15:43 ` Waiman Long
2014-05-30 15:43 ` Waiman Long
2014-05-30 15:43 ` Waiman Long
2014-05-30 15:43 ` Waiman Long
2014-05-30 15:43 ` [PATCH v11 03/16] qspinlock: Add pending bit Waiman Long
2014-05-30 15:43 ` Waiman Long
2014-05-30 15:43 ` Waiman Long
2014-05-30 15:43 ` Waiman Long
2014-05-30 15:43 ` Waiman Long
2014-05-30 15:43 ` [PATCH v11 04/16] qspinlock: Extract out the exchange of tail code word Waiman Long
2014-05-30 15:43 ` Waiman Long
2014-05-30 15:43 ` Waiman Long
2014-05-30 15:43 ` [PATCH v11 05/16] qspinlock: Optimize for smaller NR_CPUS Waiman Long
2014-05-30 15:43 ` Waiman Long
2014-05-30 15:43 ` Waiman Long
2014-05-30 15:43 ` Waiman Long
2014-05-30 15:43 ` Waiman Long
2014-05-30 15:43 ` [PATCH v11 06/16] qspinlock: prolong the stay in the pending bit path Waiman Long
2014-06-11 10:26 ` Peter Zijlstra
2014-06-11 10:26 ` Peter Zijlstra
2014-06-11 21:22 ` Long, Wai Man
2014-06-11 21:22 ` Long, Wai Man
2014-06-11 21:22 ` Long, Wai Man
2014-06-12 6:00 ` Peter Zijlstra
2014-06-12 20:54 ` Waiman Long
2014-06-12 20:54 ` Waiman Long
2014-06-15 13:12 ` Peter Zijlstra
2014-06-15 13:12 ` Peter Zijlstra
2014-06-15 13:12 ` Peter Zijlstra
2014-06-12 20:54 ` Waiman Long
2014-06-12 6:00 ` Peter Zijlstra
2014-06-12 6:00 ` Peter Zijlstra
2014-06-11 10:26 ` Peter Zijlstra
2014-05-30 15:43 ` Waiman Long
2014-05-30 15:43 ` Waiman Long
2014-05-30 15:43 ` [PATCH v11 07/16] qspinlock: Use a simple write to grab the lock, if applicable Waiman Long
2014-05-30 15:43 ` Waiman Long
2014-05-30 15:43 ` Waiman Long
2014-05-30 15:43 ` [PATCH v11 08/16] qspinlock: Prepare for unfair lock support Waiman Long
2014-05-30 15:43 ` Waiman Long
2014-05-30 15:43 ` Waiman Long
2014-05-30 15:43 ` [PATCH v11 09/16] qspinlock, x86: Allow unfair spinlock in a virtual guest Waiman Long
2014-05-30 15:43 ` Waiman Long
2014-06-11 10:54 ` Peter Zijlstra
2014-06-11 10:54 ` Peter Zijlstra
2014-06-11 11:38 ` Peter Zijlstra
2014-06-11 11:38 ` Peter Zijlstra
2014-06-11 11:38 ` Peter Zijlstra
2014-06-12 1:37 ` Long, Wai Man
2014-06-12 1:37 ` Long, Wai Man
2014-06-12 1:37 ` Long, Wai Man
2014-06-12 5:50 ` Peter Zijlstra
2014-06-12 5:50 ` Peter Zijlstra
2014-06-12 21:08 ` Waiman Long
2014-06-12 21:08 ` Waiman Long
2014-06-15 13:14 ` Peter Zijlstra [this message]
2014-06-15 13:14 ` Peter Zijlstra
2014-06-15 13:14 ` Peter Zijlstra
2014-06-12 21:08 ` Waiman Long
2014-06-12 5:50 ` Peter Zijlstra
2014-06-11 10:54 ` Peter Zijlstra
2014-05-30 15:43 ` Waiman Long
2014-05-30 15:43 ` [PATCH v11 10/16] qspinlock: Split the MCS queuing code into a separate slowerpath Waiman Long
2014-05-30 15:43 ` Waiman Long
2014-05-30 15:43 ` Waiman Long
2014-05-30 15:43 ` [PATCH v11 11/16] pvqspinlock, x86: Rename paravirt_ticketlocks_enabled Waiman Long
2014-05-30 15:43 ` Waiman Long
2014-05-30 15:43 ` Waiman Long
2014-05-30 15:43 ` [PATCH v11 12/16] pvqspinlock, x86: Add PV data structure & methods Waiman Long
2014-05-30 15:43 ` Waiman Long
2014-05-30 15:43 ` Waiman Long
2014-05-30 15:43 ` [PATCH v11 13/16] pvqspinlock: Enable coexistence with the unfair lock Waiman Long
2014-05-30 15:43 ` Waiman Long
2014-05-30 15:43 ` Waiman Long
2014-05-30 15:44 ` [PATCH v11 14/16] pvqspinlock: Add qspinlock para-virtualization support Waiman Long
2014-06-12 8:17 ` Peter Zijlstra
2014-06-12 8:17 ` Peter Zijlstra
2014-06-12 20:48 ` Waiman Long
2014-06-12 20:48 ` Waiman Long
2014-06-15 13:16 ` Peter Zijlstra
2014-06-15 13:16 ` Peter Zijlstra
2014-06-15 13:16 ` Peter Zijlstra
2014-06-17 20:59 ` Konrad Rzeszutek Wilk
2014-06-17 20:59 ` Konrad Rzeszutek Wilk
2014-06-17 20:59 ` Konrad Rzeszutek Wilk
2014-06-12 20:48 ` Waiman Long
2014-06-12 8:17 ` Peter Zijlstra
2014-05-30 15:44 ` Waiman Long
2014-05-30 15:44 ` Waiman Long
2014-05-30 15:44 ` [PATCH v11 15/16] pvqspinlock, x86: Enable PV qspinlock PV for KVM Waiman Long
2014-05-30 15:44 ` Waiman Long
2014-05-30 15:44 ` Waiman Long
2014-05-30 15:44 ` [PATCH v11 16/16] pvqspinlock, x86: Enable PV qspinlock for XEN Waiman Long
2014-05-30 15:44 ` Waiman Long
2014-05-30 15:44 ` Waiman Long
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