Re: [dpdk-dev] [PATCH 0/3] add lock-free stack support discovery

["Stanisław Kardach" <kda@semihalf.com>]

On Mon, 3 May 2021, 16:28 Olivier Matz, <olivier.matz@6wind.com> wrote:

> On Mon, May 03, 2021 at 04:21:25PM +0200, David Marchand wrote:
> > On Mon, Apr 12, 2021 at 10:29 AM Stanislaw Kardach <kda@semihalf.com>
> wrote:
> > >
> > > The lock-free stack implementation (RTE_STACK_F_LF) is supported only
> on a
> > > subset of platforms, namely x86_64 and arm64. Platforms supporting
> 128b atomics
> > > have to opt-in to a generic or C11 implementations. All other
> platforms use a
> > > stubbed implementation for push/pop operations which are basically
> NOPs.
> > > However rte_stack_create() will not fail and application can proceed
> assuming
> > > it has a working lock-free stack.
> > >
> > > This means that among other things the stack_lf fast and perf tests
> will fail
> > > as if implementation is wrong (which one can argue is). Therefore this
> patchset
> > > tries to give user a way to check whether a lock_free is supported or
> not both
> > > at compile time (build flag) and at runtime (ENOTSUP errno in
> rte_stack_create).
> > >
> > > I have added cc to stable@dpdk.org because check-git-log.sh suggested
> it. I'm
> > > not sure if adding a binary compatible change to API is worth
> stable@dpdk.org.
> > >
> > > Cc: stable@dpdk.org
> >
> > The issue was hit while porting to a new architecture.
> > The feature is broken in existing stable releases and it won't get
> > fixed by this change.
> >
> > I'd rather not backport it.
> >
> > Opinions?
>
> Agreed.
>
Agreed.

>