[dpdk-dev] [PATCH v2] ipsec: optimize with c11 atomic for sa outbound sqn update

Phil Yang phil.yang at arm.com
Thu Apr 23 19:16:27 CEST 2020


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.yang at arm.com>
Reviewed-by: Ruifeng Wang <ruifeng.wang at arm.com>
Reviewed-by: Gavin Hu <gavin.hu at arm.com>
---
v2:
split from the "generic rte atomic APIs deprecate proposal" patchset.


 lib/librte_ipsec/ipsec_sqn.h | 3 ++-
 lib/librte_ipsec/meson.build | 5 +++++
 lib/librte_ipsec/sa.h        | 2 +-
 3 files changed, 8 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/meson.build b/lib/librte_ipsec/meson.build
index fc69970..9335f28 100644
--- a/lib/librte_ipsec/meson.build
+++ b/lib/librte_ipsec/meson.build
@@ -6,3 +6,8 @@ sources = files('esp_inb.c', 'esp_outb.c', 'sa.c', 'ses.c', 'ipsec_sad.c')
 headers = files('rte_ipsec.h', 'rte_ipsec_group.h', 'rte_ipsec_sa.h', 'rte_ipsec_sad.h')
 
 deps += ['mbuf', 'net', 'cryptodev', 'security', 'hash']
+
+# for clang 32-bit compiles we need libatomic for 64-bit atomic ops
+if cc.get_id() == 'clang' and dpdk_conf.get('RTE_ARCH_64') == false
+    ext_deps += cc.find_library('atomic')
+endif
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



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