From: "Burakov, Anatoly" <anatoly.burakov@intel.com>
To: Thomas Monjalon <thomas@monjalon.net>,
Jerin Jacob Kollanukkaran <jerinj@marvell.com>,
David Marchand <david.marchand@redhat.com>
Cc: dev <dev@dpdk.org>, Ben Walker <benjamin.walker@intel.com>
Subject: Re: [dpdk-dev] [EXT] Re: [PATCH] bus/pci: fix IOVA as VA mode selection
Date: Tue, 9 Jul 2019 16:06:17 +0100 [thread overview]
Message-ID: <5fa3c363-d942-33d8-4baf-3d91653bbdf9@intel.com> (raw)
In-Reply-To: <2073381.Trv6OtLvPF@xps>
On 09-Jul-19 4:04 PM, Thomas Monjalon wrote:
> 09/07/2019 16:37, Burakov, Anatoly:
>> My view would be to always run in IOVA as VA by default and only falling
>> back to IOVA as PA if there is a need to do that. Yet, it seems that
>> whenever i try to bring this up, the response (not necessarily from you,
>> so this is not directed at you specifically) seems to be that because of
>> hotplug, we have to start in the "safest" (from device support point of
>> view) mode - that is, in IOVA as PA. Seeing how, as you claim, some
>> devices require IOVA as VA, then IOVA as PA is no longer the "safe"
>> default that all devices will support. Perhaps we can use this
>> opportunity to finally make IOVA as VA the default :)
>
> That's a good point Anatoly. We need to decide what is the safest default.
>
> About the capabilities flags, please let's agree that we want
> to express 3 cases, so we need 2 flags.
We do agree on this.
> About the preference of a mode for a device, if a mode is really
> bad for a device, I suggest to not advertise it in capabilities.
Yes, agree with that as well.
>
> In order to take a better decision, we need a summary of the
> decision algorithm per layer, involving kernel driver capabilities
> and memory capabilities.
>
This needs to be documented very well, as this seems to be a source of
great confusion for us all. If all was spelled out in the docs, we
wouldn't need this long discussion to figure out that we actually agree :D
--
Thanks,
Anatoly
next prev parent reply other threads:[~2019-07-09 15:06 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-08 14:24 [dpdk-dev] " jerinj
2019-07-08 18:39 ` David Marchand
2019-07-08 19:13 ` [dpdk-dev] [EXT] " Jerin Jacob Kollanukkaran
2019-07-09 8:39 ` Bruce Richardson
2019-07-09 9:05 ` Jerin Jacob Kollanukkaran
2019-07-09 9:32 ` Bruce Richardson
2019-07-09 9:44 ` Burakov, Anatoly
2019-07-09 11:13 ` Jerin Jacob Kollanukkaran
2019-07-09 11:40 ` Burakov, Anatoly
2019-07-09 12:11 ` Jerin Jacob Kollanukkaran
2019-07-09 13:30 ` Burakov, Anatoly
2019-07-09 13:50 ` Burakov, Anatoly
2019-07-09 14:19 ` Jerin Jacob Kollanukkaran
2019-07-09 14:00 ` Jerin Jacob Kollanukkaran
2019-07-09 14:37 ` Burakov, Anatoly
2019-07-09 15:04 ` Thomas Monjalon
2019-07-09 15:06 ` Burakov, Anatoly [this message]
2019-07-09 17:50 ` Jerin Jacob Kollanukkaran
2019-07-10 8:09 ` David Marchand
2019-07-09 14:54 ` Burakov, Anatoly
2019-07-09 14:58 ` Jerin Jacob Kollanukkaran
2019-07-09 15:02 ` Burakov, Anatoly
2019-07-09 15:12 ` Thomas Monjalon
2019-07-09 15:18 ` Burakov, Anatoly
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