-----Original Message-----
From: Thomas Monjalon <redacted>
Sent: Thursday, July 8, 2021 3:33 PM
To: Ruifeng Wang <redacted>; Jerin Jacob
[off-list ref]
Cc: Bruce Richardson <redacted>; Jan Viktorin
[off-list ref]; jerinj@marvell.com; dev@dpdk.org;
david.marchand@redhat.com; nd [off-list ref]; Honnappa Nagarahalli
[off-list ref]
Subject: Re: [dpdk-dev] [PATCH v4 3/3] build: add option to enable wait until
equal

08/07/2021 08:32, Jerin Jacob:

quoted

On Thu, Jul 8, 2021 at 11:55 AM Ruifeng Wang [off-list ref]

wrote:

quoted

quoted

From: Jerin Jacob <redacted>

quoted

On Wed, Jul 7, 2021 at 5:57 PM Bruce Richardson
[off-list ref] wrote:

quoted

On Wed, Jul 07, 2021 at 06:46:33AM +0000, Ruifeng Wang wrote:

quoted

From: Thomas Monjalon <redacted>

quoted

07/07/2021 07:48, Ruifeng Wang:

quoted

Introduce a meson option 'use_wfe' to select wait until equal

method.

quoted

quoted

quoted

quoted

quoted

quoted

quoted

The default is disable. Traditional polling loop is used.
When enabled, architecture specific mechanism is relied on
to do the wait.

Why do we need an option?
Can it be automatic to enable it when supported?

The problem is inconsistency in performance on different Arm

platforms.

quoted

quoted

quoted

We had decided that each platform needs to enable it after some

testing.

quoted

quoted

quoted

quoted

quoted

Can that not be done via variables in the cross-file for the
builds, or via automatic detection if it's a native build? Is it
likely that individual users of DPDK will be knowledgable enough
to use this option

correctly?

+1 to add this in cross-file instead of the top of config option
+as
scope if is only for arm64 builds.

Currently this option is in config/arm/meson.build (flags_common).
SoCs can build with this option enabled/disabled. And the ability is
available for both native build and cross build as cross build also goes

through meson.build.

quoted

quoted

If a SoC needs to enable the option by default, an entry and be added to

the SoC flags.

quoted

quoted

The key difference here is whether this option need to be exposed to

the top level config.

quoted

In the view of limiting top-level config options and it is specific to
Arm, I think, it better to be a cross file only option.

+1, sorry for the late notice.
I would advocate to take this patch in 21.08-rc2.

If the decision is not to expose this option in top-level config, we can just drop 3/3 patch.
Do I need to send a new version?