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From: David Laight <David.Laight@ACULAB.COM>
To: 'Benjamin Herrenschmidt' <benh@kernel.crashing.org>,
	Jason Gunthorpe <jgg@ziepe.ca>
Cc: Sinan Kaya <okaya@codeaurora.org>, Oliver <oohall@gmail.com>,
	"open list:LINUX FOR POWERPC (32-BIT AND 64-BIT)"
	<linuxppc-dev@lists.ozlabs.org>,
	"linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>
Subject: RE: RFC on writel and writel_relaxed
Date: Mon, 26 Mar 2018 11:08:45 +0000	[thread overview]
Message-ID: <58ce5b83f40f4775bec1be8db66adb0d@AcuMS.aculab.com> (raw)
In-Reply-To: <1521854626.16434.359.camel@kernel.crashing.org>

> > This is a super performance critical operation for most drivers and
> > directly impacts network performance.

Perhaps there ought to be writel_nobarrier() (etc) that never contain
any barriers at all.
This might mean that they are always just the memory operation,
but it would make it more obvious what the driver was doing.

The driver would then be explicitly responsible for all the rmb(), wmb()
and mmiowb() (etc).
Performance critical paths could then avoid all the extra barriers.

	David



WARNING: multiple messages have this Message-ID (diff)
From: David Laight <David.Laight@ACULAB.COM>
To: 'Benjamin Herrenschmidt' <benh@kernel.crashing.org>,
	Jason Gunthorpe <jgg@ziepe.ca>
Cc: Sinan Kaya <okaya@codeaurora.org>,
	"open list:LINUX FOR POWERPC (32-BIT AND 64-BIT)"
	<linuxppc-dev@lists.ozlabs.org>, Oliver <oohall@gmail.com>,
	"linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>
Subject: RE: RFC on writel and writel_relaxed
Date: Mon, 26 Mar 2018 11:08:45 +0000	[thread overview]
Message-ID: <58ce5b83f40f4775bec1be8db66adb0d@AcuMS.aculab.com> (raw)
In-Reply-To: <1521854626.16434.359.camel@kernel.crashing.org>
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  reply	other threads:[~2018-03-26 11:08 UTC|newest]

Thread overview: 216+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-03-21  3:07 RFC on writel and writel_relaxed Sinan Kaya
2018-03-21  3:40 ` Oliver
2018-03-21  3:40   ` Oliver
2018-03-21 13:53   ` Sinan Kaya
2018-03-21 13:53     ` Sinan Kaya
2018-03-21 13:58     ` Sinan Kaya
2018-03-21 13:58       ` Sinan Kaya
2018-03-26 13:43       ` Arnd Bergmann
2018-03-26 13:43         ` Arnd Bergmann
2018-03-26 16:00         ` Sinan Kaya
2018-03-26 16:00           ` Sinan Kaya
2018-03-21 14:35     ` David Laight
2018-03-21 14:35       ` David Laight
2018-03-21 15:04       ` Sinan Kaya
2018-03-22  5:24       ` Oliver
2018-03-22  8:20         ` Gabriel Paubert
2018-03-22  8:20           ` Gabriel Paubert
2018-03-22  9:25           ` Oliver
2018-03-22  9:25             ` Oliver
2018-03-22 11:25             ` Gabriel Paubert
2018-03-22 11:25               ` Gabriel Paubert
2018-03-22 10:37         ` David Laight
2018-03-22 10:37           ` David Laight
2018-03-22  4:24     ` Benjamin Herrenschmidt
2018-03-22  4:24       ` Benjamin Herrenschmidt
2018-03-22 10:15       ` Oliver
2018-03-22 10:15         ` Oliver
2018-03-22 13:52         ` Benjamin Herrenschmidt
2018-03-22 13:52           ` Benjamin Herrenschmidt
2018-03-22 17:51           ` Sinan Kaya
2018-03-22 17:51             ` Sinan Kaya
2018-03-23  0:16             ` Benjamin Herrenschmidt
2018-03-23  0:16               ` Benjamin Herrenschmidt
2018-03-23 13:42               ` Sinan Kaya
2018-03-23 13:42                 ` Sinan Kaya
2018-03-24  1:22                 ` Benjamin Herrenschmidt
2018-03-24  1:22                   ` Benjamin Herrenschmidt
2018-03-24 15:06                   ` Sinan Kaya
2018-03-24 15:06                     ` Sinan Kaya
2018-03-26 11:44               ` Will Deacon
2018-03-26 11:44                 ` Will Deacon
2018-03-26 12:11                 ` okaya
2018-03-26 12:11                   ` okaya
2018-03-26 12:42                   ` Sinan Kaya
2018-03-26 12:42                     ` Sinan Kaya
2018-03-23 16:35           ` Jason Gunthorpe
2018-03-23 16:35             ` Jason Gunthorpe
2018-03-24  1:23             ` Benjamin Herrenschmidt
2018-03-24  1:23               ` Benjamin Herrenschmidt
2018-03-26 11:08               ` David Laight [this message]
2018-03-26 11:08                 ` David Laight
2018-03-26 16:54                 ` Jason Gunthorpe
2018-03-26 16:54                   ` Jason Gunthorpe
2018-03-26 19:44                   ` Arnd Bergmann
2018-03-26 19:44                     ` Arnd Bergmann
2018-03-26 20:25                     ` Jason Gunthorpe
2018-03-26 20:25                       ` Jason Gunthorpe
2018-03-26 20:43                       ` Arnd Bergmann
2018-03-26 20:43                         ` Arnd Bergmann
2018-03-26 21:09                         ` Jason Gunthorpe
2018-03-26 21:09                           ` Jason Gunthorpe
2018-03-26 21:30                           ` Arnd Bergmann
2018-03-26 21:30                             ` Arnd Bergmann
2018-03-26 21:46                             ` Sinan Kaya
2018-03-26 21:46                               ` Sinan Kaya
2018-03-26 22:01                               ` Benjamin Herrenschmidt
2018-03-26 22:01                                 ` Benjamin Herrenschmidt
2018-03-26 22:08                                 ` Sinan Kaya
2018-03-26 22:08                                   ` Sinan Kaya
2018-03-26 22:28                                   ` Benjamin Herrenschmidt
2018-03-26 22:28                                     ` Benjamin Herrenschmidt
2018-03-26 22:27                                 ` Jason Gunthorpe
2018-03-26 22:27                                   ` Jason Gunthorpe
2018-03-26 22:36                                   ` Benjamin Herrenschmidt
2018-03-26 22:36                                     ` Benjamin Herrenschmidt
2018-03-26 22:42                                     ` Benjamin Herrenschmidt
2018-03-26 22:42                                       ` Benjamin Herrenschmidt
2018-03-26 22:50                                     ` Jason Gunthorpe
2018-03-26 22:50                                       ` Jason Gunthorpe
2018-03-26 23:59                                       ` Benjamin Herrenschmidt
2018-03-26 23:59                                         ` Benjamin Herrenschmidt
2018-03-27  1:39                                         ` Jason Gunthorpe
2018-03-27  1:39                                           ` Jason Gunthorpe
2018-03-27  7:56                                   ` Arnd Bergmann
2018-03-27  7:56                                     ` Arnd Bergmann
2018-03-27  8:56                                     ` Benjamin Herrenschmidt
2018-03-27  8:56                                       ` Benjamin Herrenschmidt
2018-03-27  9:44                                       ` Arnd Bergmann
2018-03-27  9:44                                         ` Arnd Bergmann
2018-03-27 10:00                                         ` Will Deacon
2018-03-27 10:00                                           ` Will Deacon
2018-03-27 11:23                                         ` Benjamin Herrenschmidt
2018-03-27 11:23                                           ` Benjamin Herrenschmidt
2018-03-27 12:22                                           ` okaya
2018-03-27 12:22                                             ` okaya
2018-03-27 14:12                                             ` Jason Gunthorpe
2018-03-27 14:12                                               ` Jason Gunthorpe
2018-03-27 21:27                                               ` Benjamin Herrenschmidt
2018-03-27 21:27                                                 ` Benjamin Herrenschmidt
2018-03-27  9:57                                       ` Will Deacon
2018-03-27  9:57                                         ` Will Deacon
2018-03-27 10:05                                         ` Arnd Bergmann
2018-03-27 10:05                                           ` Arnd Bergmann
2018-03-27 10:09                                           ` Will Deacon
2018-03-27 10:09                                             ` Will Deacon
2018-03-27 10:53                                             ` Arnd Bergmann
2018-03-27 10:53                                               ` Arnd Bergmann
2018-03-27 11:02                                               ` Will Deacon
2018-03-27 11:02                                                 ` Will Deacon
2018-03-27 11:05                                                 ` Arnd Bergmann
2018-03-27 11:05                                                   ` Arnd Bergmann
2018-03-27 11:25                                                 ` Benjamin Herrenschmidt
2018-03-27 11:25                                                   ` Benjamin Herrenschmidt
2018-03-27 13:20                                                 ` David Laight
2018-03-27 13:20                                                   ` David Laight
2018-03-27 13:46                                                 ` Sinan Kaya
2018-03-27 13:46                                                   ` Sinan Kaya
2018-03-27 14:36                                                   ` Will Deacon
2018-03-27 14:36                                                     ` Will Deacon
2018-03-27 21:29                                                     ` Benjamin Herrenschmidt
2018-03-27 21:29                                                       ` Benjamin Herrenschmidt
2018-03-28  8:53                                                       ` Will Deacon
2018-03-28  8:53                                                         ` Will Deacon
2018-03-28  9:00                                                         ` David Laight
2018-03-28  9:00                                                           ` David Laight
2018-03-28  9:09                                                           ` Will Deacon
2018-03-28  9:09                                                             ` Will Deacon
2018-03-28  9:56                                                             ` Benjamin Herrenschmidt
2018-03-28  9:56                                                               ` Benjamin Herrenschmidt
2018-03-28  9:50                                                         ` Benjamin Herrenschmidt
2018-03-28  9:50                                                           ` Benjamin Herrenschmidt
2018-03-28  9:55                                                           ` Arnd Bergmann
2018-03-28  9:55                                                             ` Arnd Bergmann
2018-03-28 10:01                                                             ` Benjamin Herrenschmidt
2018-03-28 10:01                                                               ` Benjamin Herrenschmidt
2018-03-28 10:13                                                               ` Will Deacon
2018-03-28 10:13                                                                 ` Will Deacon
2018-03-28 16:57                                                                 ` Jason Gunthorpe
2018-03-28 16:57                                                                   ` Jason Gunthorpe
2018-03-29  9:19                                                                   ` Will Deacon
2018-03-29  9:19                                                                     ` Will Deacon
2018-03-29 14:45                                                                     ` Jason Gunthorpe
2018-03-29 14:45                                                                       ` Jason Gunthorpe
2018-03-29 14:58                                                                       ` David Laight
2018-03-29 14:58                                                                         ` David Laight
2018-03-29 16:40                                                                         ` Jason Gunthorpe
2018-03-29 16:40                                                                           ` Jason Gunthorpe
2018-03-27 21:24                                                   ` Benjamin Herrenschmidt
2018-03-27 21:24                                                     ` Benjamin Herrenschmidt
2018-03-27 11:21                                         ` Benjamin Herrenschmidt
2018-03-27 11:21                                           ` Benjamin Herrenschmidt
2018-03-27  9:42                                     ` Will Deacon
2018-03-27  9:42                                       ` Will Deacon
2018-03-27 11:20                                       ` Benjamin Herrenschmidt
2018-03-27 11:20                                         ` Benjamin Herrenschmidt
2018-03-27 11:24                                         ` Will Deacon
2018-03-27 11:24                                           ` Will Deacon
2018-03-27 14:24                                       ` Jason Gunthorpe
2018-03-27 14:24                                         ` Jason Gunthorpe
2018-03-27 14:16                                     ` Jason Gunthorpe
2018-03-27 14:16                                       ` Jason Gunthorpe
2018-03-26 22:00                             ` Benjamin Herrenschmidt
2018-03-26 22:00                               ` Benjamin Herrenschmidt
2018-03-27 14:46                               ` Sinan Kaya
2018-03-27 15:01                                 ` Jose Abreu
2018-03-27 15:10                                 ` Will Deacon
2018-03-27 18:54                                   ` Alexander Duyck
2018-03-27 19:54                                     ` Arnd Bergmann
2018-03-27 19:54                                       ` Arnd Bergmann
2018-03-27 20:46                                       ` Arnd Bergmann
2018-03-27 20:46                                         ` Arnd Bergmann
2018-03-27 21:33                                     ` Benjamin Herrenschmidt
2018-03-28  0:39                                       ` Linus Torvalds
2018-03-28  1:03                                         ` Benjamin Herrenschmidt
2018-03-28  2:51                                           ` Linus Torvalds
2018-03-28  3:24                                             ` Sinan Kaya
2018-03-28  4:41                                               ` Benjamin Herrenschmidt
2018-03-28  6:14                                               ` Linus Torvalds
2018-03-28 11:41                                                 ` okaya
2018-03-28 15:13                                                   ` Benjamin Herrenschmidt
2018-03-28 15:55                                                     ` David Miller
2018-03-28 16:23                                                       ` Nicholas Piggin
2018-03-28 21:31                                                         ` Benjamin Herrenschmidt
2018-03-28 22:09                                                           ` Nicholas Piggin
2018-03-29  9:20                                                           ` Will Deacon
2018-03-29 13:56                                                       ` Sinan Kaya
2018-03-29 14:04                                                         ` David Miller
2018-03-29 16:29                                                         ` Arnd Bergmann
2018-03-29 16:59                                                           ` Sinan Kaya
2018-03-30  1:40                                                         ` Benjamin Herrenschmidt
2018-04-02 13:01                                                           ` Sinan Kaya
2018-03-28  4:33                                             ` Benjamin Herrenschmidt
2018-03-28  6:26                                               ` Linus Torvalds
2018-03-28  6:42                                                 ` Benjamin Herrenschmidt
2018-03-28  6:53                                                   ` Linus Torvalds
2018-03-28  6:53                                                     ` Linus Torvalds
2018-03-28  6:53                                                     ` Linus Torvalds
2018-03-28  6:56                                                     ` Benjamin Herrenschmidt
2018-03-28  7:11                                                       ` Arnd Bergmann
2018-03-28  7:42                                                         ` Benjamin Herrenschmidt
2018-03-28  9:07                                                   ` Will Deacon
2018-03-28  9:56                                                     ` Benjamin Herrenschmidt
2018-03-28 10:13                                                       ` Aw: " Lino Sanfilippo
2018-03-28 10:20                                                         ` Benjamin Herrenschmidt
2018-03-28 11:30                                                       ` David Laight
2018-03-28 11:30                                                         ` David Laight
2018-03-28 15:12                                                         ` Benjamin Herrenschmidt
2018-03-28 16:16                                                           ` David Laight
2018-03-28 16:16                                                             ` David Laight
2018-03-28  1:21                                   ` Benjamin Herrenschmidt
2018-03-27 21:35                                 ` Benjamin Herrenschmidt
2018-03-26 21:26                   ` Benjamin Herrenschmidt
2018-03-26 21:26                     ` Benjamin Herrenschmidt
2018-03-27 21:54 Alexander Duyck
2018-03-27 22:35 ` Sinan Kaya
2018-03-27 23:43 ` Benjamin Herrenschmidt

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