On Thu, Jul 8, 2021 at 11:55 AM Ruifeng Wang <[email protected]> wrote: > > > -----Original Message----- > > From: Jerin Jacob <[email protected]> > > Sent: Wednesday, July 7, 2021 8:37 PM > > To: Bruce Richardson <[email protected]> > > Cc: Ruifeng Wang <[email protected]>; [email protected]; Jan > > Viktorin <[email protected]>; [email protected]; [email protected]; > > [email protected]; nd <[email protected]>; Honnappa Nagarahalli > > <[email protected]> > > Subject: Re: [dpdk-dev] [PATCH v4 3/3] build: add option to enable wait > > until > > equal > > > > On Wed, Jul 7, 2021 at 5:57 PM Bruce Richardson > > <[email protected]> wrote: > > > > > > On Wed, Jul 07, 2021 at 06:46:33AM +0000, Ruifeng Wang wrote: > > > > > -----Original Message----- > > > > > From: Thomas Monjalon <[email protected]> > > > > > Sent: Wednesday, July 7, 2021 2:32 PM > > > > > To: Ruifeng Wang <[email protected]> > > > > > Cc: Jan Viktorin <[email protected]>; [email protected]; > > > > > Bruce Richardson <[email protected]>; [email protected]; > > > > > [email protected]; nd <[email protected]>; Honnappa > > Nagarahalli > > > > > <[email protected]> > > > > > Subject: Re: [PATCH v4 3/3] build: add option to enable wait until > > > > > equal > > > > > > > > > > 07/07/2021 07:48, Ruifeng Wang: > > > > > > Introduce a meson option 'use_wfe' to select wait until equal > > > > > > method. > > > > > > 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. > > We had decided that each platform needs to enable it after some testing. > > > > > > > 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. > If a SoC needs to enable the option by default, an entry and be added to the > SoC flags. > > The key difference here is whether this option need to be exposed to the top > level config.
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.
