[dpdk-dev] [PATCH v3 06/12] ipsec: optimize with c11 atomic for sa outbound sqn update

[Phil Yang]

For SA outbound packets, rte_atomic64_add_return is used to generate
SQN atomically. This introduced an unnecessary full barrier by calling
the '__sync' builtin implemented rte_atomic_XX API on aarch64. This
patch optimized it with c11 atomic and eliminated the expensive barrier
for aarch64.

Signed-off-by: Phil Yang <phil.y...@arm.com>
Reviewed-by: Ruifeng Wang <ruifeng.w...@arm.com>
Reviewed-by: Gavin Hu <gavin...@arm.com>
---
 lib/librte_ipsec/ipsec_sqn.h | 3 ++-
 lib/librte_ipsec/sa.h        | 2 +-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/lib/librte_ipsec/ipsec_sqn.h b/lib/librte_ipsec/ipsec_sqn.h
index 0c2f76a..e884af7 100644
--- a/lib/librte_ipsec/ipsec_sqn.h
+++ b/lib/librte_ipsec/ipsec_sqn.h
@@ -128,7 +128,8 @@ esn_outb_update_sqn(struct rte_ipsec_sa *sa, uint32_t *num)
 
        n = *num;
        if (SQN_ATOMIC(sa))
-               sqn = (uint64_t)rte_atomic64_add_return(&sa->sqn.outb.atom, n);
+               sqn = __atomic_add_fetch(&sa->sqn.outb.atom, n,
+                       __ATOMIC_RELAXED);
        else {
                sqn = sa->sqn.outb.raw + n;
                sa->sqn.outb.raw = sqn;
diff --git a/lib/librte_ipsec/sa.h b/lib/librte_ipsec/sa.h
index d22451b..cab9a2e 100644
--- a/lib/librte_ipsec/sa.h
+++ b/lib/librte_ipsec/sa.h
@@ -120,7 +120,7 @@ struct rte_ipsec_sa {
         */
        union {
                union {
-                       rte_atomic64_t atom;
+                       uint64_t atom;
                        uint64_t raw;
                } outb;
                struct {
-- 
2.7.4