From: Peter Hurley <peter@hurleysoftware.com>
To: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>
Cc: Jakub Jelinek <jakub@redhat.com>,
Mikael Pettersson <mikpelinux@gmail.com>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Richard Henderson <rth@twiddle.net>,
Oleg Nesterov <oleg@redhat.com>,
Miroslav Franc <mfranc@redhat.com>,
Paul Mackerras <paulus@samba.org>,
linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
linux-arch@vger.kernel.org, Tony Luck <tony.luck@intel.com>,
linux-ia64@vger.kernel.org
Subject: Re: bit fields && data tearing
Date: Thu, 04 Sep 2014 15:42:35 -0400 [thread overview]
Message-ID: <5408C0AB.6050801@hurleysoftware.com> (raw)
In-Reply-To: <20140904175044.4697aee4@alan.etchedpixels.co.uk>
On 09/04/2014 12:50 PM, One Thousand Gnomes wrote:
>> Besides updating the documentation, it may make sense to do something
>> arch-specific. Just bumping out storage on arches that don't need it
>> seems wasteful, as does generating bus locks on arches that don't need it.
>> Unfortunately, the code churn looks unavoidable.
>
> The arch specific is pretty much set_bit and friends. Bus locks on a
> locally owned cache line should not be very expensive on anything vaguely
> modern, while uniprocessor boxes usually only have to generate set_bit
> as a single instruction so it is interrupt safe.
Or we could give up on the Alpha.
It's not just the non-atomic bytes; we could do away with the
read_barrier_depends() which hardly any code gets correctly anyway.
Regards,
Peter Hurley
WARNING: multiple messages have this Message-ID (diff)
From: Peter Hurley <peter@hurleysoftware.com>
To: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>
Cc: Jakub Jelinek <jakub@redhat.com>,
Mikael Pettersson <mikpelinux@gmail.com>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Richard Henderson <rth@twiddle.net>,
Oleg Nesterov <oleg@redhat.com>,
Miroslav Franc <mfranc@redhat.com>,
Paul Mackerras <paulus@samba.org>,
linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
linux-arch@vger.kernel.org, Tony Luck <tony.luck@intel.com>,
linux-ia64@vger.kernel.org
Subject: Re: bit fields && data tearing
Date: Thu, 04 Sep 2014 19:42:35 +0000 [thread overview]
Message-ID: <5408C0AB.6050801@hurleysoftware.com> (raw)
In-Reply-To: <20140904175044.4697aee4@alan.etchedpixels.co.uk>
On 09/04/2014 12:50 PM, One Thousand Gnomes wrote:
>> Besides updating the documentation, it may make sense to do something
>> arch-specific. Just bumping out storage on arches that don't need it
>> seems wasteful, as does generating bus locks on arches that don't need it.
>> Unfortunately, the code churn looks unavoidable.
>
> The arch specific is pretty much set_bit and friends. Bus locks on a
> locally owned cache line should not be very expensive on anything vaguely
> modern, while uniprocessor boxes usually only have to generate set_bit
> as a single instruction so it is interrupt safe.
Or we could give up on the Alpha.
It's not just the non-atomic bytes; we could do away with the
read_barrier_depends() which hardly any code gets correctly anyway.
Regards,
Peter Hurley
WARNING: multiple messages have this Message-ID (diff)
From: Peter Hurley <peter@hurleysoftware.com>
To: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>
Cc: Jakub Jelinek <jakub@redhat.com>,
Mikael Pettersson <mikpelinux@gmail.com>,
Tony Luck <tony.luck@intel.com>,
linux-ia64@vger.kernel.org, Oleg Nesterov <oleg@redhat.com>,
linux-kernel@vger.kernel.org, Paul Mackerras <paulus@samba.org>,
linux-arch@vger.kernel.org,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
linuxppc-dev@lists.ozlabs.org, Miroslav Franc <mfranc@redhat.com>,
Richard Henderson <rth@twiddle.net>
Subject: Re: bit fields && data tearing
Date: Thu, 04 Sep 2014 15:42:35 -0400 [thread overview]
Message-ID: <5408C0AB.6050801@hurleysoftware.com> (raw)
In-Reply-To: <20140904175044.4697aee4@alan.etchedpixels.co.uk>
On 09/04/2014 12:50 PM, One Thousand Gnomes wrote:
>> Besides updating the documentation, it may make sense to do something
>> arch-specific. Just bumping out storage on arches that don't need it
>> seems wasteful, as does generating bus locks on arches that don't need it.
>> Unfortunately, the code churn looks unavoidable.
>
> The arch specific is pretty much set_bit and friends. Bus locks on a
> locally owned cache line should not be very expensive on anything vaguely
> modern, while uniprocessor boxes usually only have to generate set_bit
> as a single instruction so it is interrupt safe.
Or we could give up on the Alpha.
It's not just the non-atomic bytes; we could do away with the
read_barrier_depends() which hardly any code gets correctly anyway.
Regards,
Peter Hurley
next prev parent reply other threads:[~2014-09-04 19:42 UTC|newest]
Thread overview: 311+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-12 18:13 bit fields && data tearing Oleg Nesterov
2014-07-12 18:13 ` Oleg Nesterov
2014-07-12 20:51 ` Oleg Nesterov
2014-07-12 20:51 ` Oleg Nesterov
2014-07-12 23:34 ` Benjamin Herrenschmidt
2014-07-12 23:34 ` Benjamin Herrenschmidt
2014-07-13 12:29 ` Oleg Nesterov
2014-07-13 12:29 ` Oleg Nesterov
2014-07-13 13:15 ` Peter Hurley
2014-07-13 13:15 ` Peter Hurley
2014-07-13 22:25 ` Benjamin Herrenschmidt
2014-07-13 22:25 ` Benjamin Herrenschmidt
2014-07-15 13:54 ` Peter Hurley
2014-07-15 13:54 ` Peter Hurley
2014-07-15 15:02 ` Richard Henderson
2014-07-15 15:02 ` Richard Henderson
2014-09-03 22:51 ` Peter Hurley
2014-09-03 22:51 ` Peter Hurley
2014-09-03 22:51 ` Peter Hurley
2014-09-03 23:11 ` Benjamin Herrenschmidt
2014-09-03 23:11 ` Benjamin Herrenschmidt
2014-09-03 23:11 ` Benjamin Herrenschmidt
2014-09-03 23:11 ` Benjamin Herrenschmidt
2014-09-04 8:43 ` David Laight
2014-09-04 8:43 ` David Laight
2014-09-04 8:43 ` David Laight
2014-09-04 8:43 ` David Laight
2014-09-04 9:52 ` Benjamin Herrenschmidt
2014-09-04 9:52 ` Benjamin Herrenschmidt
2014-09-04 9:52 ` Benjamin Herrenschmidt
2014-09-04 22:14 ` H. Peter Anvin
2014-09-04 22:14 ` H. Peter Anvin
2014-09-04 22:14 ` H. Peter Anvin
2014-09-05 0:59 ` Peter Hurley
2014-09-05 0:59 ` Peter Hurley
2014-09-05 0:59 ` Peter Hurley
2014-09-05 2:08 ` H. Peter Anvin
2014-09-05 2:08 ` H. Peter Anvin
2014-09-05 2:08 ` H. Peter Anvin
2014-09-05 8:16 ` Michael Cree
2014-09-05 8:16 ` Michael Cree
2014-09-05 8:16 ` Michael Cree
2014-09-05 8:16 ` Michael Cree
2014-09-05 18:09 ` Paul E. McKenney
2014-09-05 18:09 ` Paul E. McKenney
2014-09-05 18:31 ` Paul E. McKenney
2014-09-05 18:31 ` Paul E. McKenney
2014-09-05 19:52 ` Peter Zijlstra
2014-09-05 19:52 ` Peter Zijlstra
2014-09-05 19:52 ` Peter Zijlstra
2014-09-05 20:01 ` Peter Hurley
2014-09-05 20:01 ` Peter Hurley
2014-09-05 20:01 ` Peter Hurley
2014-09-05 20:12 ` Peter Zijlstra
2014-09-05 20:12 ` Peter Zijlstra
2014-09-05 20:12 ` Peter Zijlstra
2014-09-05 20:15 ` H. Peter Anvin
2014-09-05 20:15 ` H. Peter Anvin
2014-09-05 20:15 ` H. Peter Anvin
2014-09-05 20:19 ` Paul E. McKenney
2014-09-05 20:19 ` Paul E. McKenney
2014-09-05 20:19 ` Paul E. McKenney
2014-09-05 18:50 ` Peter Hurley
2014-09-05 18:50 ` Peter Hurley
2014-09-05 19:05 ` Paul E. McKenney
2014-09-05 19:05 ` Paul E. McKenney
2014-09-05 19:05 ` Paul E. McKenney
2014-09-05 19:24 ` Peter Hurley
2014-09-05 19:24 ` Peter Hurley
2014-09-05 19:24 ` Peter Hurley
2014-09-05 20:09 ` Paul E. McKenney
2014-09-05 20:09 ` Paul E. McKenney
2014-09-05 20:09 ` Paul E. McKenney
2014-09-05 20:09 ` Paul E. McKenney
2014-09-05 19:38 ` Marc Gauthier
2014-09-05 19:38 ` Marc Gauthier
2014-09-05 19:38 ` Marc Gauthier
2014-09-05 20:14 ` Peter Hurley
2014-09-05 20:14 ` Peter Hurley
2014-09-05 20:14 ` Peter Hurley
2014-09-05 20:34 ` H. Peter Anvin
2014-09-05 20:34 ` H. Peter Anvin
2014-09-05 20:34 ` H. Peter Anvin
2014-09-05 20:42 ` Michael Cree
2014-09-05 20:42 ` Michael Cree
2014-09-05 20:42 ` Michael Cree
2014-09-05 20:43 ` Paul E. McKenney
2014-09-05 20:43 ` Paul E. McKenney
2014-09-05 20:43 ` Paul E. McKenney
2014-09-05 20:48 ` Thomas Gleixner
2014-09-05 20:48 ` Thomas Gleixner
2014-09-05 20:48 ` Thomas Gleixner
2014-09-05 21:05 ` Paul E. McKenney
2014-09-05 21:05 ` Paul E. McKenney
2014-09-05 21:05 ` Paul E. McKenney
2014-09-05 20:39 ` Michael Cree
2014-09-05 20:39 ` Michael Cree
2014-09-05 20:39 ` Michael Cree
2014-09-05 21:12 ` Peter Hurley
2014-09-05 21:12 ` Peter Hurley
2014-09-05 21:27 ` Michael Cree
2014-09-05 21:27 ` Michael Cree
2014-09-05 21:27 ` Michael Cree
2014-09-05 20:42 ` Paul E. McKenney
2014-09-05 20:42 ` Paul E. McKenney
2014-09-05 20:42 ` Paul E. McKenney
2014-09-05 2:08 ` H. Peter Anvin
2014-09-05 2:08 ` H. Peter Anvin
2014-09-05 2:08 ` H. Peter Anvin
2014-09-05 2:08 ` H. Peter Anvin
2014-09-05 15:31 ` Peter Hurley
2014-09-05 15:31 ` Peter Hurley
2014-09-05 15:31 ` Peter Hurley
2014-09-05 15:41 ` H. Peter Anvin
2014-09-05 15:41 ` H. Peter Anvin
2014-09-05 15:41 ` H. Peter Anvin
2014-09-08 17:52 ` One Thousand Gnomes
2014-09-08 17:52 ` One Thousand Gnomes
2014-09-08 17:52 ` One Thousand Gnomes
2014-09-08 17:59 ` H. Peter Anvin
2014-09-08 17:59 ` H. Peter Anvin
2014-09-08 17:59 ` H. Peter Anvin
2014-09-08 19:17 ` One Thousand Gnomes
2014-09-08 19:17 ` One Thousand Gnomes
2014-09-08 19:17 ` One Thousand Gnomes
2014-09-09 11:18 ` Peter Hurley
2014-09-09 11:18 ` Peter Hurley
2014-09-09 11:18 ` Peter Hurley
2014-09-08 22:47 ` Peter Hurley
2014-09-08 22:47 ` Peter Hurley
2014-09-08 22:47 ` Peter Hurley
2014-09-09 1:59 ` Paul E. McKenney
2014-09-09 1:59 ` Paul E. McKenney
2014-09-09 1:59 ` Paul E. McKenney
2014-09-09 11:14 ` Peter Hurley
2014-09-09 11:14 ` Peter Hurley
2014-09-09 11:14 ` Peter Hurley
2014-09-11 10:04 ` One Thousand Gnomes
2014-09-11 10:04 ` One Thousand Gnomes
2014-09-11 10:04 ` One Thousand Gnomes
2014-09-11 16:16 ` Paul E. McKenney
2014-09-11 16:16 ` Paul E. McKenney
2014-09-11 16:16 ` Paul E. McKenney
2014-09-11 20:01 ` Peter Hurley
2014-09-11 20:01 ` Peter Hurley
2014-09-11 20:01 ` Peter Hurley
2014-09-14 23:24 ` One Thousand Gnomes
2014-09-14 23:24 ` One Thousand Gnomes
2014-09-14 23:24 ` One Thousand Gnomes
2014-09-22 19:51 ` Paul E. McKenney
2014-09-22 19:51 ` Paul E. McKenney
2014-09-22 19:51 ` Paul E. McKenney
2014-09-23 18:19 ` Peter Hurley
2014-09-23 18:19 ` Peter Hurley
2014-09-23 18:19 ` Peter Hurley
2014-09-23 18:39 ` One Thousand Gnomes
2014-09-23 18:39 ` One Thousand Gnomes
2014-09-23 18:39 ` One Thousand Gnomes
2014-09-23 18:39 ` One Thousand Gnomes
2014-09-08 18:13 ` James Bottomley
2014-09-08 18:13 ` James Bottomley
2014-09-08 18:13 ` James Bottomley
2014-09-10 20:18 ` H. Peter Anvin
2014-09-10 20:18 ` H. Peter Anvin
2014-09-10 20:18 ` H. Peter Anvin
2014-09-10 21:10 ` Rob Landley
2014-09-10 21:10 ` Rob Landley
2014-09-10 21:10 ` Rob Landley
2014-09-04 8:57 ` Mikael Pettersson
2014-09-04 8:57 ` Mikael Pettersson
2014-09-04 8:57 ` Mikael Pettersson
2014-09-04 8:57 ` Mikael Pettersson
2014-09-04 9:09 ` Jakub Jelinek
2014-09-04 9:09 ` Jakub Jelinek
2014-09-04 9:09 ` Jakub Jelinek
2014-09-04 12:24 ` Peter Hurley
2014-09-04 12:24 ` Peter Hurley
2014-09-04 12:24 ` Peter Hurley
2014-09-04 12:29 ` Jakub Jelinek
2014-09-04 12:29 ` Jakub Jelinek
2014-09-04 12:29 ` Jakub Jelinek
2014-09-04 16:50 ` One Thousand Gnomes
2014-09-04 16:50 ` One Thousand Gnomes
2014-09-04 16:50 ` One Thousand Gnomes
2014-09-04 16:50 ` One Thousand Gnomes
2014-09-04 19:42 ` Peter Hurley [this message]
2014-09-04 19:42 ` Peter Hurley
2014-09-04 19:42 ` Peter Hurley
2014-09-04 22:16 ` H. Peter Anvin
2014-09-04 22:16 ` H. Peter Anvin
2014-09-04 22:16 ` H. Peter Anvin
2014-09-05 0:17 ` Paul E. McKenney
2014-09-05 0:17 ` Paul E. McKenney
2014-09-05 0:17 ` Paul E. McKenney
2014-09-05 1:57 ` Peter Hurley
2014-09-05 1:57 ` Peter Hurley
2014-09-05 1:57 ` Peter Hurley
2014-09-05 2:11 ` James Bottomley
2014-09-05 2:11 ` James Bottomley
2014-09-05 2:11 ` James Bottomley
2014-09-05 2:47 ` Peter Hurley
2014-09-05 2:47 ` Peter Hurley
2014-09-05 2:47 ` Peter Hurley
2014-09-05 4:06 ` Paul E. McKenney
2014-09-05 4:06 ` Paul E. McKenney
2014-09-05 4:06 ` Paul E. McKenney
2014-09-05 8:30 ` David Laight
2014-09-05 8:30 ` David Laight
2014-09-05 8:30 ` David Laight
2014-09-05 8:30 ` David Laight
2014-09-05 12:31 ` Peter Hurley
2014-09-05 12:31 ` Peter Hurley
2014-09-05 12:31 ` Peter Hurley
2014-09-05 12:37 ` David Laight
2014-09-05 12:37 ` David Laight
2014-09-05 12:37 ` David Laight
2014-09-05 12:37 ` David Laight
2014-09-05 16:17 ` Peter Hurley
2014-09-05 16:17 ` Peter Hurley
2014-09-05 16:17 ` Peter Hurley
2014-09-25 16:12 ` Pavel Machek
2014-09-25 16:12 ` Pavel Machek
2014-09-25 16:12 ` Pavel Machek
2014-09-07 5:07 ` James Bottomley
2014-09-07 5:07 ` James Bottomley
2014-09-07 5:07 ` James Bottomley
2014-09-07 16:21 ` Paul E. McKenney
2014-09-07 16:21 ` Paul E. McKenney
2014-09-07 16:21 ` Paul E. McKenney
2014-09-07 19:04 ` James Bottomley
2014-09-07 19:04 ` James Bottomley
2014-09-07 19:04 ` James Bottomley
2014-09-07 20:41 ` Peter Hurley
2014-09-07 20:41 ` Peter Hurley
2014-09-07 20:41 ` Peter Hurley
2014-09-08 5:50 ` James Bottomley
2014-09-08 5:50 ` James Bottomley
2014-09-08 5:50 ` James Bottomley
2014-09-08 20:45 ` Chris Metcalf
2014-09-08 20:45 ` Chris Metcalf
2014-09-08 20:45 ` Chris Metcalf
2014-09-08 20:45 ` Chris Metcalf
2014-09-08 22:43 ` James Bottomley
2014-09-08 22:43 ` James Bottomley
2014-09-08 22:43 ` James Bottomley
2014-09-09 2:27 ` H. Peter Anvin
2014-09-09 2:27 ` H. Peter Anvin
2014-09-09 2:27 ` H. Peter Anvin
2014-09-09 2:27 ` H. Peter Anvin
2014-09-09 8:11 ` Arnd Bergmann
2014-09-09 8:11 ` Arnd Bergmann
2014-09-09 8:11 ` Arnd Bergmann
2014-09-08 23:30 ` Peter Hurley
2014-09-08 23:30 ` Peter Hurley
2014-09-08 23:30 ` Peter Hurley
2014-09-09 2:56 ` James Bottomley
2014-09-09 2:56 ` James Bottomley
2014-09-09 2:56 ` James Bottomley
2014-09-09 3:20 ` H. Peter Anvin
2014-09-09 3:20 ` H. Peter Anvin
2014-09-09 3:20 ` H. Peter Anvin
2014-09-09 4:30 ` H. Peter Anvin
2014-09-09 4:30 ` H. Peter Anvin
2014-09-09 4:30 ` H. Peter Anvin
2014-09-09 4:30 ` H. Peter Anvin
2014-09-09 10:40 ` Peter Hurley
2014-09-09 10:40 ` Peter Hurley
2014-09-09 10:40 ` Peter Hurley
2014-09-10 21:48 ` James Bottomley
2014-09-10 21:48 ` James Bottomley
2014-09-10 21:48 ` James Bottomley
2014-09-10 23:50 ` Peter Hurley
2014-09-10 23:50 ` Peter Hurley
2014-09-10 23:50 ` Peter Hurley
2014-09-11 10:23 ` Will Deacon
2014-09-11 10:23 ` Will Deacon
2014-09-11 10:23 ` Will Deacon
2014-09-07 23:00 ` Paul E. McKenney
2014-09-07 23:00 ` Paul E. McKenney
2014-09-07 23:00 ` Paul E. McKenney
2014-09-07 23:17 ` H. Peter Anvin
2014-09-07 23:17 ` H. Peter Anvin
2014-09-07 23:17 ` H. Peter Anvin
2014-09-07 23:36 ` Paul E. McKenney
2014-09-07 23:36 ` Paul E. McKenney
2014-09-07 23:36 ` Paul E. McKenney
2014-09-07 23:39 ` H. Peter Anvin
2014-09-07 23:39 ` H. Peter Anvin
2014-09-07 23:39 ` H. Peter Anvin
2014-09-08 5:56 ` James Bottomley
2014-09-08 5:56 ` James Bottomley
2014-09-08 5:56 ` James Bottomley
2014-09-08 18:12 ` H. Peter Anvin
2014-09-08 18:12 ` H. Peter Anvin
2014-09-08 18:12 ` H. Peter Anvin
2014-09-08 19:09 ` James Bottomley
2014-09-08 19:09 ` James Bottomley
2014-09-08 19:09 ` James Bottomley
2014-09-08 19:12 ` H. Peter Anvin
2014-09-08 19:12 ` H. Peter Anvin
2014-09-08 19:12 ` H. Peter Anvin
2014-09-08 19:12 ` H. Peter Anvin
2014-09-08 19:12 ` H. Peter Anvin
2014-09-08 19:12 ` H. Peter Anvin
2014-09-08 19:12 ` H. Peter Anvin
2014-09-08 22:39 ` James Bottomley
2014-09-08 22:39 ` James Bottomley
2014-09-08 22:39 ` James Bottomley
2014-09-09 2:30 ` H. Peter Anvin
2014-09-09 2:30 ` H. Peter Anvin
2014-09-09 2:30 ` H. Peter Anvin
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=5408C0AB.6050801@hurleysoftware.com \
--to=peter@hurleysoftware.com \
--cc=benh@kernel.crashing.org \
--cc=gnomes@lxorguk.ukuu.org.uk \
--cc=jakub@redhat.com \
--cc=linux-arch@vger.kernel.org \
--cc=linux-ia64@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=mfranc@redhat.com \
--cc=mikpelinux@gmail.com \
--cc=oleg@redhat.com \
--cc=paulmck@linux.vnet.ibm.com \
--cc=paulus@samba.org \
--cc=rth@twiddle.net \
--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 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.