netdev - [PATCH][net-next] vxlan: reduce dirty cache line in vxlan_find

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <1534649768-24074-1-git-send-email-lirongqing@baidu.com>
Date:   Sun, 19 Aug 2018 11:36:08 +0800
From:   Li RongQing <lirongqing@...du.com>
To:     netdev@...r.kernel.org
Subject: [PATCH][net-next] vxlan: reduce dirty cache line in vxlan_find_mac

vxlan_find_mac() unconditionally set f->used for every packet,
this cause a cache miss for every packet, since remote, hlist
and used of vxlan_fdb share the same cacheline.

With this change f->used is set only if not equal to jiffies
This gives up to 5% speed-up with small packets.

Signed-off-by: Zhang Yu <zhangyu31@...du.com>
Signed-off-by: Li RongQing <lirongqing@...du.com>
---
 drivers/net/vxlan.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
index ababba37d735..e5d236595206 100644
--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -464,7 +464,7 @@ static struct vxlan_fdb *vxlan_find_mac(struct vxlan_dev *vxlan,
 	struct vxlan_fdb *f;
 
 	f = __vxlan_find_mac(vxlan, mac, vni);
-	if (f)
+	if (f && f->used != jiffies)
 		f->used = jiffies;
 
 	return f;
-- 
2.16.2