Re: [PATCH v4 08/10] test-pmd: declare lcore_count atomic

[Andre Muezerie <andremue@linux.microsoft.com>]

On Fri, Feb 21, 2025 at 08:40:17AM +0000, Konstantin Ananyev wrote:
> 
> 
> > Compiling with MSVC results in the error below:
> > 
> > app/test/test_ring_perf.c(197): error C7712: address argument to atomic
> >     operation must be a pointer to an atomic integer,
> >     'volatile unsigned int *' is not valid
> > 
> > The fix is to mark lcore_count as atomic.
> > 
> > Signed-off-by: Andre Muezerie <andremue@linux.microsoft.com>
> > Signed-off-by: Chengwen Feng <fengchengwen@huawei.com>
> > ---
> >  app/test/test_ring_perf.c | 6 +-----
> >  1 file changed, 1 insertion(+), 5 deletions(-)
> > 
> > diff --git a/app/test/test_ring_perf.c b/app/test/test_ring_perf.c
> > index 57cd04a124..366e256323 100644
> > --- a/app/test/test_ring_perf.c
> > +++ b/app/test/test_ring_perf.c
> > @@ -34,7 +34,7 @@ struct lcore_pair {
> >  	unsigned c1, c2;
> >  };
> > 
> > -static volatile unsigned lcore_count = 0;
> > +static RTE_ATOMIC(unsigned int) lcore_count;
> 
> But for not-MSVC builds RTE_ATOMIC() by default means nothing.
> If you are removing volatile, then I think, you need to fix the code to ensure
> that all reads/writes to this var are done with atomic ops.
> Or have both -  volatile and RTE_ATOMIC()

Good point.
I'll use both volatile and RTE_ATOMIC() in the next series.

> 
> 
> >  static void
> >  test_ring_print_test_string(unsigned int api_type, int esize,
> > @@ -193,11 +193,7 @@ enqueue_dequeue_bulk_helper(const unsigned int flag, struct thread_params *p)
> >  	unsigned int n_remaining;
> >  	const unsigned int bulk_n = bulk_sizes[p->ring_params->bulk_sizes_i];
> > 
> > -#ifdef RTE_USE_C11_MEM_MODEL
> >  	if (rte_atomic_fetch_add_explicit(&lcore_count, 1, rte_memory_order_relaxed) + 1 != 2)
> > -#else
> > -	if (__sync_add_and_fetch(&lcore_count, 1) != 2)
> > -#endif
> >  		while(lcore_count != 2)
> >  			rte_pause();
> > 
> > --
> > 2.48.1.vfs.0.0
> >