[dpdk-dev] [PATCH v2 0/8] use GCC's C11 atomic builtins for test

[Honnappa Nagarahalli]

<snip>
> 
> On Tue, Jun 15, 2021 at 09:54:51PM -0500, Joyce Kong wrote:
> > Since C11 memory model is adopted in DPDK now[1], use GCC's atomic
> > builtins in test cases.
> 
> as previously discussed these atomics are not "C11" they are direct use of gcc
> builtins. please don't incorporate C11 into the title of the patches or commit
> messages since it isn't.
GCC supports 2 types of built-in atomics, __atomic_xxx[1] and __sync_xxx [2]. We need a way to distinguish between them. We are using "C11" as [1] says they match C++11 memory model.

[1] https://gcc.gnu.org/onlinedocs/gcc/_005f_005fatomic-Builtins.html
[2] https://gcc.gnu.org/onlinedocs/gcc-4.1.1/gcc/Atomic-Builtins.html

> 
> please do not integrate a patch that directly uses gcc builtins and extensions
> please maintain abstractions under the rte_ namespace.
This is just another wrapper which is not required according to the current requirements we are working with.

> specifically this patch substantially increases coupling to a single compiler
> implementation reducing portability.
> 
> as previously requested, please establish at a minimum macros in the rte_
> namespace for this.
This needs to be discussed at the Techboard. I have CCed the Techboard. The Techboard meets once in 2 weeks. The details are at [3]. Next meeting is on 6/30 at 10am CST. Can you please attend and make your case?

Alternately, you can send an email to techboard at dpdk.org explaining your case and we will debate and make a decision.

[3] https://core.dpdk.org/techboard/

> 
> thanks.
> 
> >
> > [1]
> > https://www.dpdk.org/blog/2021/03/26/dpdk-adopts-the-c11-memory-
> model/
> >
> > v2:
> >  Use rte_wait_until_equal() instead of original sync loops.
> >  <David Marchand>
> >
> > v1:
> >  The initial version.
> >
> > Joyce Kong (8):
> >   test/ticketlock: use GCC atomic builtins for lcores sync
> >   test/spinlock: use GCC atomic builtins for lcores sync
> >   test/rwlock: use GCC atomic builtins for lcores sync
> >   test/mcslock: use GCC atomic builtins for lcores sync
> >   test/mempool: remove unused variable for lcores sync
> >   test/mempool_perf: use GCC atomic builtins for lcores sync
> >   test/service_cores: use GCC atomic builtins for lock sync
> >   test/rcu: use GCC atomic builtins for data sync
> >
> >  app/test/test_mcslock.c       | 14 +++--
> >  app/test/test_mempool.c       |  5 --
> >  app/test/test_mempool_perf.c  | 11 ++--
> > app/test/test_rcu_qsbr_perf.c | 98 +++++++++++++++++------------------
> >  app/test/test_rwlock.c        | 10 ++--
> >  app/test/test_service_cores.c | 36 +++++++------
> >  app/test/test_spinlock.c      |  9 ++--
> >  app/test/test_ticketlock.c    | 10 ++--
> >  8 files changed, 91 insertions(+), 102 deletions(-)
> >
> > --
> > 2.17.1