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From: Ruifeng Wang <Ruifeng.Wang@arm.com>
To: Stephen Hemminger <stephen@networkplumber.org>
Cc: Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>,
	Konstantin Ananyev <konstantin.ananyev@intel.com>,
	"dev@dpdk.org" <dev@dpdk.org>,
	"david.marchand@redhat.com" <david.marchand@redhat.com>,
	"thomas@monjalon.net" <thomas@monjalon.net>,
	"jerinj@marvell.com" <jerinj@marvell.com>, nd <nd@arm.com>,
	Gavin Hu <Gavin.Hu@arm.com>, Steve Capper <Steve.Capper@arm.com>,
	Ola Liljedahl <Ola.Liljedahl@arm.com>, nd <nd@arm.com>
Subject: Re: [dpdk-dev] [PATCH v3 2/2] ring: use wfe to wait for ring tail update on aarch64
Date: Thu, 29 Apr 2021 14:35:35 +0000	[thread overview]
Message-ID: <AM5PR0802MB2465DFAC10C2339F053B34C29E5F9@AM5PR0802MB2465.eurprd08.prod.outlook.com> (raw)
In-Reply-To: <20210428101714.2e5da560@hermes.local>

> -----Original Message-----
> From: Stephen Hemminger <stephen@networkplumber.org>
> Sent: Thursday, April 29, 2021 1:17 AM
> To: Ruifeng Wang <Ruifeng.Wang@arm.com>
> Cc: Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>; Konstantin
> Ananyev <konstantin.ananyev@intel.com>; dev@dpdk.org;
> david.marchand@redhat.com; thomas@monjalon.net; jerinj@marvell.com;
> nd <nd@arm.com>; Gavin Hu <Gavin.Hu@arm.com>; Steve Capper
> <Steve.Capper@arm.com>; Ola Liljedahl <Ola.Liljedahl@arm.com>
> Subject: Re: [dpdk-dev] [PATCH v3 2/2] ring: use wfe to wait for ring tail
> update on aarch64
> 
> On Sun, 25 Apr 2021 05:56:53 +0000
> Ruifeng Wang <ruifeng.wang@arm.com> wrote:
> 
> > Instead of polling for tail to be updated, use wfe instruction.
> >
> > Signed-off-by: Gavin Hu <gavin.hu@arm.com>
> > Signed-off-by: Ruifeng Wang <ruifeng.wang@arm.com>
> > Reviewed-by: Steve Capper <steve.capper@arm.com>
> > Reviewed-by: Ola Liljedahl <ola.liljedahl@arm.com>
> > Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
> > Acked-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
> 
> Looks ok to me, but it does raise an interesting question.
> Shouldn't the original code have been using atomic load to look at ht->tail.
> 
> This another place where "volatile considered harmful" applies.

Do you mean 'volatile' should be removed from rte_wait_until_equal_xxx parameters?


  reply	other threads:[~2021-04-29 14:35 UTC|newest]

Thread overview: 60+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-24  7:07 [dpdk-dev] [PATCH v1 0/2] Use WFE for spinlock and ring Gavin Hu
2020-04-24  7:07 ` [dpdk-dev] [PATCH v1 1/2] spinlock: use wfe to reduce contention on aarch64 Gavin Hu
2020-04-24  7:07 ` [dpdk-dev] [PATCH v1 2/2] ring: use wfe to wait for ring tail update " Gavin Hu
2020-04-24 13:23   ` Ananyev, Konstantin
2020-04-26  8:41     ` Gavin Hu
2020-04-24 14:46   ` Honnappa Nagarahalli
2020-04-26  8:33     ` Gavin Hu
2020-04-26  8:39 ` [dpdk-dev] [PATCH v2 0/2] Use WFE for spinlock and ring Gavin Hu
2020-05-01  9:47   ` Ananyev, Konstantin
2020-05-03 14:54   ` David Marchand
2020-05-03 21:31     ` Honnappa Nagarahalli
2020-09-25 14:30       ` David Marchand
2021-03-25 14:58         ` David Marchand
2021-04-25  6:06           ` Ruifeng Wang
2021-04-25 15:56             ` Thomas Monjalon
2020-04-26  8:39 ` [dpdk-dev] [PATCH v2 1/2] spinlock: use wfe to reduce contention on aarch64 Gavin Hu
2020-04-28 12:22   ` Jerin Jacob
2020-04-26  8:39 ` [dpdk-dev] [PATCH v2 2/2] ring: use wfe to wait for ring tail update " Gavin Hu
2021-04-25  5:56 ` [dpdk-dev] Use WFE for spinlock and ring Ruifeng Wang
2021-04-25  5:56   ` [dpdk-dev] [PATCH v3 1/2] spinlock: use wfe to reduce contention on aarch64 Ruifeng Wang
2021-04-25  5:56   ` [dpdk-dev] [PATCH v3 2/2] ring: use wfe to wait for ring tail update " Ruifeng Wang
2021-04-26  5:38     ` Jerin Jacob
2021-04-28 17:17     ` Stephen Hemminger
2021-04-29 14:35       ` Ruifeng Wang [this message]
2021-04-29 15:05         ` Stephen Hemminger
2021-05-07  8:25           ` Ruifeng Wang
2021-04-28  7:42   ` [dpdk-dev] Use WFE for spinlock and ring David Marchand
2021-04-28  9:30     ` Ruifeng Wang
2021-04-28 11:13       ` Thomas Monjalon
2021-04-29 14:28         ` Ruifeng Wang
2021-04-29 15:20           ` Thomas Monjalon
2021-04-30  9:16             ` Bruce Richardson
2021-04-30 13:41               ` Honnappa Nagarahalli
2021-04-30 14:19                 ` Bruce Richardson
2021-05-07 10:18                   ` Ruifeng Wang
2021-05-07 10:24                     ` Bruce Richardson
2021-07-05  8:51                       ` David Marchand
2021-07-05 10:21                         ` Ruifeng Wang
2021-07-07 14:47   ` Stephen Hemminger
2021-07-08  9:41     ` Ruifeng Wang
2021-07-08 16:58       ` Honnappa Nagarahalli
2021-07-07  5:43 ` [dpdk-dev] [PATCH v4 0/3] " Ruifeng Wang
2021-07-07  5:43   ` [dpdk-dev] [PATCH v4 1/3] spinlock: use wfe to reduce contention on aarch64 Ruifeng Wang
2021-07-07  5:43   ` [dpdk-dev] [PATCH v4 2/3] ring: use wfe to wait for ring tail update " Ruifeng Wang
2021-07-07  5:43   ` [dpdk-dev] [PATCH v4 3/3] build: add option to enable wait until equal Ruifeng Wang
2021-07-07 12:15     ` David Marchand
2021-07-07  5:48 ` [dpdk-dev] [PATCH v4 0/3] Use WFE for spinlock and ring Ruifeng Wang
2021-07-07  5:48   ` [dpdk-dev] [PATCH v4 1/3] spinlock: use wfe to reduce contention on aarch64 Ruifeng Wang
2021-07-07  5:48   ` [dpdk-dev] [PATCH v4 2/3] ring: use wfe to wait for ring tail update " Ruifeng Wang
2021-07-07  5:48   ` [dpdk-dev] [PATCH v4 3/3] build: add option to enable wait until equal Ruifeng Wang
2021-07-07  6:32     ` Thomas Monjalon
2021-07-07  6:46       ` Ruifeng Wang
2021-07-07 12:27         ` Bruce Richardson
2021-07-07 12:36           ` Jerin Jacob
2021-07-08  6:25             ` Ruifeng Wang
2021-07-08  6:32               ` Jerin Jacob
2021-07-08  7:32                 ` Thomas Monjalon
2021-07-08  9:21                   ` Ruifeng Wang
2021-07-08 10:28                     ` Thomas Monjalon
2021-07-09 18:39   ` [dpdk-dev] [PATCH v4 0/3] Use WFE for spinlock and ring Thomas Monjalon

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