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From: Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>
To: Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>,
	"dev@dpdk.org" <dev@dpdk.org>,
	Ruifeng Wang <Ruifeng.Wang@arm.com>,
	"jerinj@marvell.com" <jerinj@marvell.com>,
	"hemant.agrawal@nxp.com" <hemant.agrawal@nxp.com>,
	"Ajit Khaparde (ajit.khaparde@broadcom.com)"
	<ajit.khaparde@broadcom.com>,
	"igorch@amazon.com" <igorch@amazon.com>,
	"thomas@monjalon.net" <thomas@monjalon.net>,
	"viacheslavo@mellanox.com" <viacheslavo@mellanox.com>,
	 "arybchenko@solarflare.com" <arybchenko@solarflare.com>,
	"bruce.richardson@intel.com" <bruce.richardson@intel.com>
Cc: nd <nd@arm.com>,
	Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>,
	nd <nd@arm.com>
Subject: Re: [dpdk-dev] [PATCH v2] eal: adjust barriers for IO on Armv8-a
Date: Sat, 27 Jun 2020 19:25:09 +0000	[thread overview]
Message-ID: <DB6PR0802MB2216003B78CE6DD398D51D7898900@DB6PR0802MB2216.eurprd08.prod.outlook.com> (raw)
In-Reply-To: <20200627191208.34520-1-honnappa.nagarahalli@arm.com>

Hi Jerin,
	You had a comment earlier about deprecating rte_cio_[rw]mb. Let me know if you are ok with this patch and I can add those changes (replace references to rte_cio_[rw]mb with rte_io_[rw]mb and a deprecation notice).

Thanks,
Honnappa

> -----Original Message-----
> From: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
> Sent: Saturday, June 27, 2020 2:12 PM
> To: dev@dpdk.org; Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>;
> Ruifeng Wang <Ruifeng.Wang@arm.com>; jerinj@marvell.com;
> hemant.agrawal@nxp.com; Ajit Khaparde (ajit.khaparde@broadcom.com)
> <ajit.khaparde@broadcom.com>; igorch@amazon.com;
> thomas@monjalon.net; viacheslavo@mellanox.com;
> arybchenko@solarflare.com; bruce.richardson@intel.com
> Cc: nd <nd@arm.com>
> Subject: [PATCH v2] eal: adjust barriers for IO on Armv8-a
> 
> Change the barrier APIs for IO to reflect that Armv8-a is other-multi-copy
> atomicity memory model.
> 
> Armv8-a memory model has been strengthened to require other-multi-copy
> atomicity. This property requires memory accesses from an observer to
> become visible to all other observers simultaneously [3]. This means
> 
> a) A write arriving at an endpoint shared between multiple CPUs is
>    visible to all CPUs
> b) A write that is visible to all CPUs is also visible to all other
>    observers in the shareability domain
> 
> This allows for using cheaper DMB instructions in the place of DSB for devices
> that are visible to all CPUs (i.e. devices that DPDK caters to).
> 
> Please refer to [1], [2] and [3] for more information.
> 
> [1]
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id
> =22ec71615d824f4f11d38d0e55a88d8956b7e45f
> [2] https://www.youtube.com/watch?v=i6DayghhA8Q
> [3] https://www.cl.cam.ac.uk/~pes20/armv8-mca/
> 
> Signed-off-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
> Tested-by: Ruifeng Wang <ruifeng.wang@arm.com>
> ---
>  lib/librte_eal/arm/include/rte_atomic_64.h | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/lib/librte_eal/arm/include/rte_atomic_64.h
> b/lib/librte_eal/arm/include/rte_atomic_64.h
> index 7b7099cdc..e42f69edc 100644
> --- a/lib/librte_eal/arm/include/rte_atomic_64.h
> +++ b/lib/librte_eal/arm/include/rte_atomic_64.h
> @@ -1,6 +1,6 @@
>  /* SPDX-License-Identifier: BSD-3-Clause
>   * Copyright(c) 2015 Cavium, Inc
> - * Copyright(c) 2019 Arm Limited
> + * Copyright(c) 2020 Arm Limited
>   */
> 
>  #ifndef _RTE_ATOMIC_ARM64_H_
> @@ -19,11 +19,11 @@ extern "C" {
>  #include <rte_compat.h>
>  #include <rte_debug.h>
> 
> -#define rte_mb() asm volatile("dsb sy" : : : "memory")
> +#define rte_mb() asm volatile("dmb osh" : : : "memory")
> 
> -#define rte_wmb() asm volatile("dsb st" : : : "memory")
> +#define rte_wmb() asm volatile("dmb oshst" : : : "memory")
> 
> -#define rte_rmb() asm volatile("dsb ld" : : : "memory")
> +#define rte_rmb() asm volatile("dmb oshld" : : : "memory")
> 
>  #define rte_smp_mb() asm volatile("dmb ish" : : : "memory")
> 
> @@ -37,9 +37,9 @@ extern "C" {
> 
>  #define rte_io_rmb() rte_rmb()
> 
> -#define rte_cio_wmb() asm volatile("dmb oshst" : : : "memory")
> +#define rte_cio_wmb() rte_wmb()
> 
> -#define rte_cio_rmb() asm volatile("dmb oshld" : : : "memory")
> +#define rte_cio_rmb() rte_rmb()
> 
>  /*------------------------ 128 bit atomic operations -------------------------*/
> 
> --
> 2.17.1


  reply	other threads:[~2020-06-27 19:25 UTC|newest]

Thread overview: 70+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-13 12:38 [dpdk-dev] [PATCH RFC v1 0/6] barrier fix and optimization for mlx5 on aarch64 Gavin Hu
2020-02-13 12:38 ` [dpdk-dev] [PATCH RFC v1 1/6] net/mlx5: relax the barrier for UAR write Gavin Hu
2020-02-13 12:38 ` [dpdk-dev] [PATCH RFC v1 2/6] net/mlx5: use cio barrier before the BF WQE Gavin Hu
2020-02-13 12:38 ` [dpdk-dev] [PATCH RFC v1 3/6] net/mlx5: add missing barrier Gavin Hu
2020-02-13 12:38 ` [dpdk-dev] [PATCH RFC v1 4/6] net/mlx5: add descriptive comment for a barrier Gavin Hu
2020-02-13 12:38 ` [dpdk-dev] [PATCH RFC v1 5/6] net/mlx5: non-cacheable mapping defaulted for aarch64 Gavin Hu
2020-02-13 12:38 ` [dpdk-dev] [PATCH RFC v1 6/6] net/mlx5: relaxed ordering for multi-packet RQ buffer refcnt Gavin Hu
2020-04-10 16:41 ` [dpdk-dev] [PATCH RFC v2 0/7] introduce new barrier class and use it for mlx5 PMD Gavin Hu
2020-04-10 17:20   ` Andrew Rybchenko
2020-04-11  3:46     ` Gavin Hu
2020-04-13  9:51       ` Andrew Rybchenko
2020-04-13 16:46         ` Gavin Hu
2020-05-11 18:06   ` [dpdk-dev] [RFC] eal: adjust barriers for IO on Armv8-a Honnappa Nagarahalli
2020-05-12  6:18     ` Ruifeng Wang
2020-05-12  6:42       ` Jerin Jacob
2020-05-12  8:02         ` Ruifeng Wang
2020-05-12  8:28           ` Jerin Jacob
2020-05-12 21:44           ` Honnappa Nagarahalli
2020-05-13 14:49             ` Jerin Jacob
2020-05-14  1:02               ` Honnappa Nagarahalli
2020-06-27 19:12   ` [dpdk-dev] [PATCH v2] " Honnappa Nagarahalli
2020-06-27 19:25     ` Honnappa Nagarahalli [this message]
2020-06-30  5:13       ` Jerin Jacob
2020-07-03 18:57   ` [dpdk-dev] [PATCH v3 1/3] " Honnappa Nagarahalli
2020-07-03 18:57     ` [dpdk-dev] [PATCH v3 2/3] doc: update armv8-a IO barrier changes Honnappa Nagarahalli
2020-07-05  0:57       ` Jerin Jacob
2020-07-03 18:57     ` [dpdk-dev] [PATCH v3 3/3] doc: update deprecation of CIO barrier APIs Honnappa Nagarahalli
2020-07-05  0:57       ` Jerin Jacob
2020-07-07 20:19       ` Ajit Khaparde
2020-07-08 11:05       ` Ananyev, Konstantin
2020-07-06 23:43   ` [dpdk-dev] [PATCH v4 1/3] eal: adjust barriers for IO on Armv8-a Honnappa Nagarahalli
2020-07-06 23:43     ` [dpdk-dev] [PATCH v4 2/3] doc: update armv8-a IO barrier changes Honnappa Nagarahalli
2020-07-07  8:36       ` David Marchand
2020-07-07 18:37         ` Honnappa Nagarahalli
2020-07-06 23:43     ` [dpdk-dev] [PATCH v4 3/3] doc: update deprecation of CIO barrier APIs Honnappa Nagarahalli
2020-07-07  8:39       ` David Marchand
2020-07-07 20:14       ` David Christensen
2020-07-08 11:49       ` David Marchand
2020-04-10 16:41 ` [dpdk-dev] [PATCH RFC v2 1/7] eal: introduce new class of barriers for DMA use cases Gavin Hu
2020-04-10 16:41 ` [dpdk-dev] [PATCH RFC v2 2/7] net/mlx5: dmb for immediate doorbell ring on aarch64 Gavin Hu
2020-04-10 16:41 ` [dpdk-dev] [PATCH RFC v2 3/7] net/mlx5: relax barrier to order UAR writes " Gavin Hu
2020-04-10 16:41 ` [dpdk-dev] [PATCH RFC v2 4/7] net/mlx5: relax barrier for aarch64 Gavin Hu
2020-04-10 16:41 ` [dpdk-dev] [PATCH RFC v2 5/7] net/mlx5: add descriptive comment for a barrier Gavin Hu
2020-04-10 16:41 ` [dpdk-dev] [PATCH RFC v2 6/7] net/mlx5: relax ordering for multi-packet RQ buffer refcnt Gavin Hu
2020-06-23  8:26   ` [dpdk-dev] [PATCH v3] net/mlx5: relaxed " Phil Yang
2020-07-13  3:02     ` Phil Yang
2020-07-20 23:21       ` Alexander Kozyrev
2020-07-21  1:55         ` Phil Yang
2020-07-21  3:58           ` Alexander Kozyrev
2020-07-21  4:03             ` Honnappa Nagarahalli
2020-07-21  4:11               ` Alexander Kozyrev
2020-07-22 12:06                 ` Phil Yang
2020-07-23  4:47         ` Honnappa Nagarahalli
2020-07-23  6:11           ` Phil Yang
2020-07-23 16:53             ` Alexander Kozyrev
2020-07-27 14:52               ` Phil Yang
2020-08-06  2:43                 ` Alexander Kozyrev
2020-08-11  5:20                   ` Honnappa Nagarahalli
2020-09-02 21:52                     ` Alexander Kozyrev
2020-09-03  2:55                       ` Phil Yang
2020-09-09 13:29                         ` Alexander Kozyrev
2020-09-10  1:34                           ` Honnappa Nagarahalli
2020-09-03  2:53     ` [dpdk-dev] [PATCH v4] " Phil Yang
2020-09-10  1:30       ` Honnappa Nagarahalli
2020-09-10  1:36         ` Alexander Kozyrev
2020-09-29 15:22           ` Phil Yang
2020-09-30 12:44             ` Slava Ovsiienko
2020-09-30 12:52               ` Raslan Darawsheh
2020-09-30 13:57       ` Raslan Darawsheh
2020-04-10 16:41 ` [dpdk-dev] [PATCH RFC v2 7/7] doc: clarify one configuration in mlx5 guide Gavin Hu

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