Re: [PATCH v5 0/6] replace rte atomics with GCC builtin atomics

[Tyler Retzlaff <roretzla@linux.microsoft.com>]

On Fri, Jun 09, 2023 at 05:01:53PM +0200, David Marchand wrote:
> On Tue, Jun 6, 2023 at 11:45 PM Tyler Retzlaff
> <roretzla@linux.microsoft.com> wrote:
> >
> > Replace the use of rte_atomic.h types and functions, instead use GCC
> > supplied C++11 memory model builtins.
> >
> > This series covers the libraries and drivers that are built on Windows.
> >
> > The code has be converted to use the __atomic builtins but there are
> > additional during conversion I notice that there may be some issues
> > that need to be addressed.
> >
> > I'll comment in the patches where my concerns are so the maintainers
> > may comment.
> >
> > v5:
> >   * use relaxed ordering for counter increments in net/ring patch
> >   * remove note comments from net/ring patch
> >
> > v4:
> >
> >   * drop patch for lib/ring it will be provided by ARM / Honnappa
> >   * rebase for changes in dma/idxd merge
> >   * adapt __atomic_fetch_sub(...) - 1 == 0 to be (__atomic_fetch_sub(...) == 1)
> >     as per feedback.
> >   * drop one /* NOTE: review for potential ordering optimization */ since
> >     the note reference non-critical to perf control path.
> >
> >   note:
> >
> >   Remainder of the NOTE comments have been retained since there
> >   seems to be no consensus but stronger opinion/argument to keep
> >   expressed. while I generally agree that changes should not
> >   include ``TODO'' style comments I also agree that without these
> >   comments in your face people are very unlikely to feel compelled
> >   to make the review they are trying to solicit without them. if
> >   it is absolute that the series won't be merged with them then I
> >   will remove them, but please be explicit soon.
> >
> > v3:
> >   * style, don't use c99 comments
> >
> > v2:
> >   * comment code where optimizations may be possible now that memory
> >     order can be specified.
> >   * comment code where operations should potentially be atomic so that
> >     maintainers can review.
> >   * change a couple of variables labeled as counters to be unsigned.
> >
> > Tyler Retzlaff (6):
> >   stack: replace rte atomics with GCC builtin atomics
> >   dma/idxd: replace rte atomics with GCC builtin atomics
> >   net/ice: replace rte atomics with GCC builtin atomics
> >   net/ixgbe: replace rte atomics with GCC builtin atomics
> >   net/null: replace rte atomics with GCC builtin atomics
> >   net/ring: replace rte atomics with GCC builtin atomics
> >
> >  drivers/dma/idxd/idxd_internal.h |  3 +--
> >  drivers/dma/idxd/idxd_pci.c      | 11 ++++++-----
> >  drivers/net/ice/ice_dcf.c        |  1 -
> >  drivers/net/ice/ice_dcf_ethdev.c |  1 -
> >  drivers/net/ice/ice_ethdev.c     | 12 ++++++++----
> >  drivers/net/ixgbe/ixgbe_bypass.c |  1 -
> >  drivers/net/ixgbe/ixgbe_ethdev.c | 18 ++++++++++++------
> >  drivers/net/ixgbe/ixgbe_ethdev.h |  3 ++-
> >  drivers/net/ixgbe/ixgbe_flow.c   |  1 -
> >  drivers/net/ixgbe/ixgbe_rxtx.c   |  1 -
> >  drivers/net/null/rte_eth_null.c  | 28 ++++++++++++++++++----------
> >  drivers/net/ring/rte_eth_ring.c  | 20 ++++++++++----------
> >  lib/stack/rte_stack_lf_generic.h | 16 +++++++++-------
> >  13 files changed, 66 insertions(+), 50 deletions(-)
> 
> I am not really enthousiastic about those NOTE:.
> I would prefer we get an explicit go/nogo from each maintainers, but
> this did not happen.
> I think that this indicates that those NOTE: will rot in the code now.
> 
> Thomas proposed to track those NOTE: in the release announce mail and
> that we ping maintainers regularly.
> Let's see how it goes.

Let's leave it for one release cycle, if with the the announce mail
maintainers take no action within that time I'll commit to going
through and cleaning them out before 23.11 rc1.

> 
> I am merging this series so we can progress on the $SUBJECT.
> Series applied, thanks.

Thanks David, this will allow forward progress.

> 
> 
> Tyler, about the patch on the ring library that was dropped by got no
> viable alternative, I'll wait for a decision from ARM and you.

I'll wait for Honnappa to follow up and we'll decide what to do when he
does.

> 
> -- 
> David Marchand