[dpdk-dev] Using C11 atomic semantic

Honnappa Nagarahalli Honnappa.Nagarahalli at arm.com
Mon Jul 20 21:36:13 CEST 2020


<snip>
> 
> 20/07/2020 17:44, Honnappa Nagarahalli:
> > From: Thomas Monjalon <thomas at monjalon.net>
> > >
> > > In the techboard of April 22, it has been decided to block patches
> > > using rte_atomicNN_xx and rte_smp_*mb APIs, starting DPDK 20.08.
> > > Meeting minutes:
> > > 	http://mails.dpdk.org/archives/dev/2020-April/165143.html
> > > Deprecation notice:
> > > 	http://doc.dpdk.org/guides/rel_notes/deprecation.html
> > >
> > > Some doc has been submitted to help understanding how to manage
> atomics:
> > > 	http://doc
> 	.dpdk.org/guides/prog_guide/writing_efficient_code.html#locks-and-
> > > atomic-operations
> > >
> > > Unfortunately the tool to check new code was merged last week:
> > > 	http://git.dpdk.org/dpdk/commit/?id=f1602b4a86
> > >
> > > As a consequence, I propose to apply the "reject rule" starting DPDK 20.11.
> >
> > As far as I know no patch with rte_atomic has gone in 20.08 so far. Are there
> any patches in RC2/RC3 that need rte_atomic APIs?
> 
> Yes we have the case of an additional call added in 20.08-rc2 in mlx5 (not yet
> converted to C11 atomics).
There is one patch that Phil had put together [1] for mlx5.
Since this is a unconverted module, suggest allowing for 20.08 instead of removing the 'reject rule' patch.

[1] https://patches.dpdk.org/patch/72007/

> 
> > > Can we make this rule better advertised with an announce message?
> >
> > Do you mean an email on dpdk-announce mailing list?
> 
> Yes
> 
> > > Are the current technical explanations enough?
> >
> > The documentation patch you referenced above covers most common cases
> people will encounter. Even the rte_ring/rte_stack algorithms work on the
> same principles.
> >
> > > If not, it would be wonderful to have a blog post explaining the
> > > details, as part of an announce.
> >
> > This is in the works. The plan is to send it to you soon and get it out along
> with the release.
> 
> Great
> 



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