From: Will Deacon <will.deacon@arm.com>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: ralf@linux-mips.org, tony.luck@intel.com, fenghua.yu@intel.com,
linux-arch@vger.kernel.org
Subject: Re: Fw: Getting an early start on C++ standards issues...
Date: Fri, 26 Feb 2016 15:22:38 +0000 [thread overview]
Message-ID: <20160226152238.GE29125@arm.com> (raw)
In-Reply-To: <20160226145057.GA6734@linux.vnet.ibm.com>
On Fri, Feb 26, 2016 at 06:50:57AM -0800, Paul E. McKenney wrote:
> Hello!
Hi Paul,
> Do ARM, MIPS, and IA64 data/address/control dependencies apply to loads
> and stores from vector instructions? The use case appears to be that the
> dependency chain is headed by a normal load instruction, and a dependency
> to a later vector load/store is desired.
>
> Any other weakly ordered architectures with vector instructions?
We certainly have instructions that don't honour address dependencies,
for example LDNP (load non-temporal pair), and these could be used by
variants of memcpy. x86 has something similar with MOVNTDQA[1].
It's highly likely that we'd consider similar relaxations for extensions
to our vector instructions in future revisions of the ARM architecture,
so I don't think we should generally rely on address dependencies
providing order for vectorised code.
Will
[1] http://www.felixcloutier.com/x86/MOVNTDQA.html
next prev parent reply other threads:[~2016-02-26 15:22 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-26 14:50 Fw: Getting an early start on C++ standards issues Paul E. McKenney
2016-02-26 15:22 ` Will Deacon [this message]
2016-02-26 21:33 ` Paul E. McKenney
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=20160226152238.GE29125@arm.com \
--to=will.deacon@arm.com \
--cc=fenghua.yu@intel.com \
--cc=linux-arch@vger.kernel.org \
--cc=paulmck@linux.vnet.ibm.com \
--cc=ralf@linux-mips.org \
--cc=tony.luck@intel.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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox