[1/7] ring: replace rte atomics with GCC builtin atomics
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Commit Message
Replace the use of rte_atomic.h types and functions, instead use GCC
supplied C++11 memory model builtins.
Signed-off-by: Tyler Retzlaff <roretzla@linux.microsoft.com>
---
lib/ring/rte_ring_core.h | 1 -
lib/ring/rte_ring_generic_pvt.h | 10 ++++++----
2 files changed, 6 insertions(+), 5 deletions(-)
Comments
On Fri, Mar 17, 2023 at 01:19:42PM -0700, Tyler Retzlaff wrote:
> Replace the use of rte_atomic.h types and functions, instead use GCC
> supplied C++11 memory model builtins.
>
> Signed-off-by: Tyler Retzlaff <roretzla@linux.microsoft.com>
> ---
> lib/ring/rte_ring_core.h | 1 -
> lib/ring/rte_ring_generic_pvt.h | 10 ++++++----
> 2 files changed, 6 insertions(+), 5 deletions(-)
>
> diff --git a/lib/ring/rte_ring_core.h b/lib/ring/rte_ring_core.h
> index 82b2370..b9c7860 100644
> --- a/lib/ring/rte_ring_core.h
> +++ b/lib/ring/rte_ring_core.h
> @@ -31,7 +31,6 @@
> #include <rte_config.h>
> #include <rte_memory.h>
> #include <rte_lcore.h>
> -#include <rte_atomic.h>
> #include <rte_branch_prediction.h>
> #include <rte_memzone.h>
> #include <rte_pause.h>
> diff --git a/lib/ring/rte_ring_generic_pvt.h b/lib/ring/rte_ring_generic_pvt.h
> index 5acb6e5..f9a15b6 100644
> --- a/lib/ring/rte_ring_generic_pvt.h
> +++ b/lib/ring/rte_ring_generic_pvt.h
> @@ -92,8 +92,9 @@
> if (is_sp)
> r->prod.head = *new_head, success = 1;
> else
> - success = rte_atomic32_cmpset(&r->prod.head,
> - *old_head, *new_head);
> + success = __atomic_compare_exchange_n(&r->prod.head,
> + old_head, *new_head, 0,
> + __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST);
> } while (unlikely(success == 0));
> return n;
> }
> @@ -162,8 +163,9 @@
> rte_smp_rmb();
> success = 1;
> } else {
> - success = rte_atomic32_cmpset(&r->cons.head, *old_head,
> - *new_head);
> + success = __atomic_compare_exchange_n(&r->cons.head,
> + old_head, *new_head, 0,
> + __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST);
> }
> } while (unlikely(success == 0));
> return n;
just something i noticed and not related to this change.
i note that old_head for both __rte_ring_move_prod_head and
__rte_ring_move_con_head are performing a non-atomic load to
initialize `*old_head` probably not the best idea.
@@ -31,7 +31,6 @@
#include <rte_config.h>
#include <rte_memory.h>
#include <rte_lcore.h>
-#include <rte_atomic.h>
#include <rte_branch_prediction.h>
#include <rte_memzone.h>
#include <rte_pause.h>
@@ -92,8 +92,9 @@
if (is_sp)
r->prod.head = *new_head, success = 1;
else
- success = rte_atomic32_cmpset(&r->prod.head,
- *old_head, *new_head);
+ success = __atomic_compare_exchange_n(&r->prod.head,
+ old_head, *new_head, 0,
+ __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST);
} while (unlikely(success == 0));
return n;
}
@@ -162,8 +163,9 @@
rte_smp_rmb();
success = 1;
} else {
- success = rte_atomic32_cmpset(&r->cons.head, *old_head,
- *new_head);
+ success = __atomic_compare_exchange_n(&r->cons.head,
+ old_head, *new_head, 0,
+ __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST);
}
} while (unlikely(success == 0));
return n;