From: Christoph Lameter <clameter@sgi.com>
To: Andrea Arcangeli <andrea@qumranet.com>
Cc: steiner@sgi.com, Peter Zijlstra <a.p.zijlstra@chello.nl>,
linux-mm@kvack.org, Kanoj Sarcar <kanojsarcar@yahoo.com>,
Roland Dreier <rdreier@cisco.com>,
Steve Wise <swise@opengridcomputing.com>,
linux-kernel@vger.kernel.org, Avi Kivity <avi@qumranet.com>,
kvm-devel@lists.sourceforge.net, daniel.blueman@quadrics.com,
Robin Holt <holt@sgi.com>,
general@lists.openfabrics.org, Hugh Dickins <hugh@veritas.com>
Subject: Re: [patch 5/9] Convert anon_vma lock to rw_sem and refcount
Date: Wed, 2 Apr 2008 11:15:26 -0700 (PDT) [thread overview]
Message-ID: <Pine.LNX.4.64.0804021107520.27337@schroedinger.engr.sgi.com> (raw)
In-Reply-To: <20080402175058.GR19189@duo.random>
On Wed, 2 Apr 2008, Andrea Arcangeli wrote:
> On Tue, Apr 01, 2008 at 01:55:36PM -0700, Christoph Lameter wrote:
> > This results in f.e. the Aim9 brk performance test to got down by 10-15%.
>
> I guess it's more likely because of overscheduling for small crtitical
> sections, did you counted the total number of context switches? I
> guess there will be a lot more with your patch applied. That
> regression is a showstopper and it is the reason why I've suggested
> before to add a CONFIG_XPMEM or CONFIG_MMU_NOTIFIER_SLEEP config
> option to make the VM locks sleep capable only when XPMEM=y
> (PREEMPT_RT will enable it too). Thanks for doing the benchmark work!
There are more context switches if locks are contended.
But that has actually also some good aspects because we avoid busy loops
and can potentially continue work in another process.
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next prev parent reply other threads:[~2008-04-02 18:15 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-04-01 20:55 [ofa-general] [patch 0/9] [RFC] EMM Notifier V2 Christoph Lameter
2008-04-01 20:55 ` [patch 1/9] EMM Notifier: The notifier calls Christoph Lameter
2008-04-02 6:49 ` [ofa-general] " Andrea Arcangeli
2008-04-02 10:59 ` Robin Holt
2008-04-02 11:16 ` Andrea Arcangeli
2008-04-02 14:26 ` Robin Holt
2008-04-02 17:59 ` [ofa-general] " Christoph Lameter
2008-04-02 19:03 ` [ofa-general] EMM: Fixup return value handling of emm_notify() Christoph Lameter
2008-04-02 21:25 ` [ofa-general] " Andrea Arcangeli
2008-04-02 21:33 ` Christoph Lameter
2008-04-03 10:40 ` Peter Zijlstra
2008-04-03 15:00 ` Andrea Arcangeli
2008-04-03 19:14 ` Christoph Lameter
2008-04-02 21:05 ` [ofa-general] EMM: Require single threadedness for registration Christoph Lameter
2008-04-02 22:01 ` [ofa-general] " Andrea Arcangeli
2008-04-02 22:06 ` Christoph Lameter
2008-04-02 22:17 ` Andrea Arcangeli
2008-04-02 22:41 ` Christoph Lameter
2008-04-03 1:24 ` EMM: disable other notifiers before register and unregister Christoph Lameter
2008-04-03 10:40 ` [ofa-general] " Peter Zijlstra
2008-04-03 15:29 ` Andrea Arcangeli
2008-04-03 19:20 ` [ofa-general] " Christoph Lameter
2008-04-03 20:23 ` Christoph Lameter
2008-04-04 12:30 ` Andrea Arcangeli
2008-04-04 20:20 ` [ofa-general] [PATCH] mmu notifier #v11 Andrea Arcangeli
2008-04-04 22:06 ` Christoph Lameter
2008-04-05 0:23 ` [ofa-general] " Andrea Arcangeli
2008-04-07 5:45 ` Christoph Lameter
2008-04-07 6:02 ` [ofa-general] " Andrea Arcangeli
2008-04-02 21:53 ` [ofa-general] Re: [patch 1/9] EMM Notifier: The notifier calls Andrea Arcangeli
2008-04-02 21:54 ` Christoph Lameter
2008-04-02 22:09 ` Andrea Arcangeli
2008-04-02 23:04 ` Christoph Lameter
2008-04-01 20:55 ` [ofa-general] [patch 2/9] Move tlb flushing into free_pgtables Christoph Lameter
2008-04-01 20:55 ` [ofa-general] [patch 3/9] Convert i_mmap_lock to i_mmap_sem Christoph Lameter
2008-04-01 20:55 ` [patch 4/9] Remove tlb pointer from the parameters of unmap vmas Christoph Lameter
2008-04-01 20:55 ` [patch 5/9] Convert anon_vma lock to rw_sem and refcount Christoph Lameter
2008-04-02 17:50 ` Andrea Arcangeli
2008-04-02 18:15 ` Christoph Lameter [this message]
2008-04-02 21:56 ` [ofa-general] " Andrea Arcangeli
2008-04-02 21:56 ` Christoph Lameter
2008-04-02 22:12 ` Andrea Arcangeli
2008-04-01 20:55 ` [patch 6/9] This patch exports zap_page_range as it is needed by XPMEM Christoph Lameter
2008-04-01 20:55 ` [patch 7/9] Locking rules for taking multiple mmap_sem locks Christoph Lameter
2008-04-01 20:55 ` [patch 8/9] XPMEM: The device driver Christoph Lameter
2008-04-01 20:55 ` [patch 9/9] XPMEM: Simple example Christoph Lameter
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