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From: Gavin Hu <gavin.hu@arm.com>
To: dev@dpdk.org
Cc: nd@arm.com, david.marchand@redhat.com, thomas@monjalon.net,
 jerinj@marvell.com, xiaolong.ye@intel.com, Honnappa.Nagarahalli@arm.com,
 ruifeng.wang@arm.com, phil.yang@arm.com, joyce.kong@arm.com,
 steve.capper@arm.com
Date: Fri,  6 Mar 2020 13:04:27 +0800
Message-Id: <20200306050427.66114-4-gavin.hu@arm.com>
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References: <20200306050427.66114-1-gavin.hu@arm.com>
Subject: [dpdk-dev] [PATCH v1 3/3] net/i40e: auto-vectorization to speed up
	Tx free
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Tx mbuf free is a hotspot for i40e on aarch64, as there are no
inter-loop dependencies, it is safe to enable auto-vectorization
to speed up.

This patch showed 2~3% performance lift on ThunderX2 and no degradation
on Arm N1SDP. The test case is single core RFC2544 zero-loss test.

Signed-off-by: Gavin Hu <gavin.hu@arm.com>
Reviewed-by: Steve Capper <steve.capper@arm.com>
---
 drivers/net/i40e/i40e_rxtx_vec_common.h | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/net/i40e/i40e_rxtx_vec_common.h b/drivers/net/i40e/i40e_rxtx_vec_common.h
index 0e6ffa007..fc0fa45d4 100644
--- a/drivers/net/i40e/i40e_rxtx_vec_common.h
+++ b/drivers/net/i40e/i40e_rxtx_vec_common.h
@@ -98,6 +98,11 @@ i40e_tx_free_bufs(struct i40e_tx_queue *txq)
 	if (likely(m != NULL)) {
 		free[0] = m;
 		nb_free = 1;
+#if defined(__clang__)
+#pragma clang loop vectorize(assume_safety)
+#elif defined(__GNUC__)
+#pragma GCC ivdep
+#endif
 		for (i = 1; i < n; i++) {
 			m = rte_pktmbuf_prefree_seg(txep[i].mbuf);
 			if (likely(m != NULL)) {
-- 
2.17.1