From 740cecb24f52a945c0d40d6073ff0b2acc5c0616 Mon Sep 17 00:00:00 2001 From: Jerin Jacob Date: Mon, 12 Feb 2018 18:43:43 +0530 Subject: [PATCH] ethdev: fix data alignment The struct rte_eth_dev_data is used in ethdev fastpath routines and it not aligned to cache line size. This patch fixes the ethdev data alignment. The alignment was broken from the "first public release" changeset where ethdev data address was aligned only to the first port. Remaining ports alignment was defined by the size of the struct (rte_eth_dev_data). This scheme is not guaranteed to be cache line aligned all the time. "ethdev: add port ownership" change set introduced a rte_eth_dev_shared_data container for port ownership change, This resulted in rte_eth_dev->data memory for the first port also as cache unaligned. Added a compiler alignment attribute to make sure rte_eth_dev->data always cache aligned so that CPU/compiler 1) Avoid sharing the element with another cache line 2) Can load/store the elements in struct rte_eth_dev_data as naturally aligned. Some platform like thunderX could see performance regression of 1% at "ethdev: add port ownership" change set with 1 port/1 queue l3fwd application and this patch fixes that regression. example command: sudo ./examples/l3fwd/build/l3fwd -c 0xff00 -- -p 0x1 --config="(0,0,9)" Fixes: af75078fece3 ("first public release") Fixes: 5b7ba31148a8 ("ethdev: add port ownership") Cc: stable@dpdk.org Signed-off-by: Jerin Jacob Signed-off-by: Pavan Nikhilesh Acked-by: Thomas Monjalon --- lib/librte_ether/rte_ethdev_core.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/lib/librte_ether/rte_ethdev_core.h b/lib/librte_ether/rte_ethdev_core.h index 315b317232..e5681e4668 100644 --- a/lib/librte_ether/rte_ethdev_core.h +++ b/lib/librte_ether/rte_ethdev_core.h @@ -601,7 +601,7 @@ struct rte_eth_dev_data { struct rte_vlan_filter_conf vlan_filter_conf; /**< VLAN filter configuration. */ struct rte_eth_dev_owner owner; /**< The port owner. */ -}; +} __rte_cache_aligned; /** * @internal -- 2.20.1