[dpdk-dev] [PATCH v3] 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. Use c11 atomics with RELAXED ordering for outbound SQN
update instead of rte_atomic ops which enforce unnecessary barriers on
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>
---
v3:
1. since libatomic dependency for 32-bit clang added globally, so remove
the redundant code.
2. collapse union outb to unint64_t outb as the rte_atomic is no needed.

v2:
split from the "generic rte atomic APIs deprecate proposal" patchset.

 lib/librte_ipsec/ipsec_sqn.h | 6 +++---
 lib/librte_ipsec/sa.c        | 2 +-
 lib/librte_ipsec/sa.h        | 5 +----
 3 files changed, 5 insertions(+), 8 deletions(-)

diff --git a/lib/librte_ipsec/ipsec_sqn.h b/lib/librte_ipsec/ipsec_sqn.h
index 0c2f76a..2636cb1 100644
--- a/lib/librte_ipsec/ipsec_sqn.h
+++ b/lib/librte_ipsec/ipsec_sqn.h
@@ -128,10 +128,10 @@ 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, n, __ATOMIC_RELAXED);
        else {
-               sqn = sa->sqn.outb.raw + n;
-               sa->sqn.outb.raw = sqn;
+               sqn = sa->sqn.outb + n;
+               sa->sqn.outb = sqn;
        }
 
        /* overflow */
diff --git a/lib/librte_ipsec/sa.c b/lib/librte_ipsec/sa.c
index ada195c..e59189d 100644
--- a/lib/librte_ipsec/sa.c
+++ b/lib/librte_ipsec/sa.c
@@ -283,7 +283,7 @@ esp_outb_init(struct rte_ipsec_sa *sa, uint32_t hlen)
 {
        uint8_t algo_type;
 
-       sa->sqn.outb.raw = 1;
+       sa->sqn.outb = 1;
 
        algo_type = sa->algo_type;
 
diff --git a/lib/librte_ipsec/sa.h b/lib/librte_ipsec/sa.h
index d22451b..508dd2b 100644
--- a/lib/librte_ipsec/sa.h
+++ b/lib/librte_ipsec/sa.h
@@ -119,10 +119,7 @@ struct rte_ipsec_sa {
         * place from other frequently accesed data.
         */
        union {
-               union {
-                       rte_atomic64_t atom;
-                       uint64_t raw;
-               } outb;
+               uint64_t outb;
                struct {
                        uint32_t rdidx; /* read index */
                        uint32_t wridx; /* write index */
-- 
2.7.4