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From: Jerin Jacob <jerinjacobk@gmail.com>
To: "Gavin Hu (Arm Technology China)" <Gavin.Hu@arm.com>
Cc: Sunil Kumar Kori <skori@marvell.com>,
	"jerinj@marvell.com" <jerinj@marvell.com>,
	 Nithin Dabilpuram <ndabilpuram@marvell.com>,
	Vamsi Attunuru <vattunuru@marvell.com>,
	 "dev@dpdk.org" <dev@dpdk.org>, Harman Kalra <hkalra@marvell.com>,
	 Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>,
	nd <nd@arm.com>
Subject: Re: [dpdk-dev] [PATCH v3 2/2] common/octeontx2: add polling based response mbox message
Date: Tue, 17 Dec 2019 16:44:07 +0530	[thread overview]
Message-ID: <CALBAE1Op+G5a+SUne4V+B4eq6+m0z9_APktZQkH8M5fkCma34A@mail.gmail.com> (raw)
In-Reply-To: <VI1PR08MB537696E37E73B088EFD987988F500@VI1PR08MB5376.eurprd08.prod.outlook.com>

> > +mbox_poll(struct otx2_mbox *mbox, uint32_t wait)
> > +{
> > +     uint32_t timeout = 0, sleep = 1;
> > +     uint64_t rsp_reg = 0;
> > +     uintptr_t reg_addr;
> > +
> > +     reg_addr = mbox->reg_base + mbox->intr_offset;
> > +     while (!rsp_reg) {
> The first iteration of (!rsp_reg) always evaluate to 'true'.
> Why not use do .. while to save one iteration?
> > +             rte_rmb();
> Rte_rmb is overkill, how is reg_addr mapped(what is the memory attribute? WC? cacheable? )
> If it is a PCI mmaped region, then rte_io_barrier is okay, I am proposing to relax the io barrier for aarch64 as a compiler barrier.
>  http://patches.dpdk.org/patch/61662/

It is the device memory and Linux kernel(_CPU_ not IO) is updating the
memory on the other side. I think,
we would need rte_smp_rmb() here. Since it was slow-path code, added
the full barrier here.
I think it is OK to change rte_smp_rmb() not to rte_io_* version. Correct?

  reply	other threads:[~2019-12-17 11:14 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-25 11:35 [dpdk-dev] [PATCH 1/5] drivers/octeontx2: allow experimental symbols Sunil Kumar Kori
2019-11-25 11:35 ` [dpdk-dev] [PATCH v3 2/5] eal: add API to check if its interrupt context Sunil Kumar Kori
2019-11-25 11:35 ` [dpdk-dev] [PATCH 3/5] common/octeontx2: add interrupt offset to mbox structure Sunil Kumar Kori
2019-11-25 11:35 ` [dpdk-dev] [PATCH 4/5] common/octeontx2: add polling based response mbox message Sunil Kumar Kori
2019-11-25 11:35 ` [dpdk-dev] [PATCH 5/5] common/octeontx2: enhancing mbox APIs to get response Sunil Kumar Kori
2019-11-26  6:15 ` [dpdk-dev] [PATCH v2 1/5] drivers/octeontx2: allow experimental symbols Sunil Kumar Kori
2019-11-26 16:21   ` Thomas Monjalon
2019-11-27  8:34     ` [dpdk-dev] [EXT] " Sunil Kumar Kori
2019-11-27  9:42       ` Thomas Monjalon
2019-11-27 10:22   ` [dpdk-dev] [PATCH v2 1/4] eal: add API to check if its interrupt context Sunil Kumar Kori
2019-11-27 10:22     ` [dpdk-dev] [PATCH v2 2/4] common/octeontx2: add interrupt offset to mbox structure Sunil Kumar Kori
2019-11-27 10:22     ` [dpdk-dev] [PATCH v2 3/4] common/octeontx2: add polling based response mbox message Sunil Kumar Kori
2019-11-27 10:22     ` [dpdk-dev] [PATCH v2 4/4] drivers/octeontx2: enhancing mbox APIs to get response Sunil Kumar Kori
2019-11-28  0:03     ` [dpdk-dev] [PATCH v2 1/4] eal: add API to check if its interrupt context Stephen Hemminger
2019-11-28  8:10       ` [dpdk-dev] [EXT] " Harman Kalra
2019-11-28 16:45         ` Stephen Hemminger
2019-12-04 16:23           ` Harman Kalra
2019-12-16 10:39     ` [dpdk-dev] [PATCH v3 1/2] " Sunil Kumar Kori
2019-12-16 10:39       ` [dpdk-dev] [PATCH v3 2/2] common/octeontx2: add polling based response mbox message Sunil Kumar Kori
2019-12-17  8:02         ` Gavin Hu (Arm Technology China)
2019-12-17 11:14           ` Jerin Jacob [this message]
2019-12-18  2:45             ` Gavin Hu
2019-12-17 10:42         ` [dpdk-dev] [PATCH v4 1/2] eal: add API to check if its interrupt context Sunil Kumar Kori
2019-12-17 10:42           ` [dpdk-dev] [PATCH v4 2/2] common/octeontx2: add polling based response mbox message Sunil Kumar Kori
2019-12-17 16:53         ` [dpdk-dev] [PATCH v4 1/2] eal: add API to check if its interrupt context Sunil Kumar Kori
2019-12-17 16:53           ` [dpdk-dev] [PATCH v4 2/2] common/octeontx2: add polling based response mbox message Sunil Kumar Kori
2019-12-18  2:54             ` Gavin Hu
2019-12-18  7:07           ` [dpdk-dev] [PATCH v5 1/2] eal: add API to check if its interrupt context Sunil Kumar Kori
2019-12-18  7:07             ` [dpdk-dev] [PATCH v5 2/2] common/octeontx2: add polling based response mbox message Sunil Kumar Kori
2019-12-20  6:56               ` [dpdk-dev] [PATCH v6 1/2] eal: add API to check if its interrupt context Sunil Kumar Kori
2019-12-20  6:56                 ` [dpdk-dev] [PATCH v6 2/2] common/octeontx2: add polling based response mbox message Sunil Kumar Kori
2020-01-14  8:41                   ` Jerin Jacob
2020-01-14 10:17                     ` Thomas Monjalon
2020-01-14  9:04                   ` [dpdk-dev] [PATCH v7 1/2] eal: add API to check if its interrupt context Sunil Kumar Kori
2020-01-14  9:04                     ` [dpdk-dev] [PATCH v7 2/2] common/octeontx2: add polling based response mbox message Sunil Kumar Kori
2020-01-21  8:37                       ` Sunil Kumar Kori
2020-02-06 15:35                     ` [dpdk-dev] [PATCH v7 1/2] eal: add API to check if its interrupt context David Marchand
2020-01-14  8:37                 ` [dpdk-dev] [PATCH v6 " Jerin Jacob

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