linux-kernel - [PATCH v4 5/7] proc: Reduce cache miss in xfrm_statistics_seq

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Message-Id: <1474877355-12920-6-git-send-email-hejianet@gmail.com>
Date:   Mon, 26 Sep 2016 16:09:13 +0800
From:   Jia He <hejianet@...il.com>
To:     netdev@...r.kernel.org
Cc:     linux-sctp@...r.kernel.org, linux-kernel@...r.kernel.org,
        davem@...emloft.net, Alexey Kuznetsov <kuznet@....inr.ac.ru>,
        James Morris <jmorris@...ei.org>,
        Hideaki YOSHIFUJI <yoshfuji@...ux-ipv6.org>,
        Patrick McHardy <kaber@...sh.net>,
        Vlad Yasevich <vyasevich@...il.com>,
        Neil Horman <nhorman@...driver.com>,
        Steffen Klassert <steffen.klassert@...unet.com>,
        Herbert Xu <herbert@...dor.apana.org.au>,
        marcelo.leitner@...il.com, Jia He <hejianet@...il.com>
Subject: [PATCH v4 5/7] proc: Reduce cache miss in xfrm_statistics_seq_show

This is to use the generic interface snmp_get_cpu_field{,64}_batch to
aggregate the data by going through all the items of each cpu sequentially.

Signed-off-by: Jia He <hejianet@...il.com>
---
 net/xfrm/xfrm_proc.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/net/xfrm/xfrm_proc.c b/net/xfrm/xfrm_proc.c
index 9c4fbd8..2b280fc 100644
--- a/net/xfrm/xfrm_proc.c
+++ b/net/xfrm/xfrm_proc.c
@@ -52,10 +52,16 @@ static int xfrm_statistics_seq_show(struct seq_file *seq, void *v)
 {
 	struct net *net = seq->private;
 	int i;
+	unsigned long buff[LINUX_MIB_XFRMMAX];
+
+	memset(buff, 0, sizeof(unsigned long) * LINUX_MIB_XFRMMAX);
+
+	snmp_get_cpu_field_batch(buff, xfrm_mib_list,
+				 net->mib.xfrm_statistics);
 	for (i = 0; xfrm_mib_list[i].name; i++)
 		seq_printf(seq, "%-24s\t%lu\n", xfrm_mib_list[i].name,
-			   snmp_fold_field(net->mib.xfrm_statistics,
-					   xfrm_mib_list[i].entry));
+						buff[i]);
+
 	return 0;
 }
 
-- 
2.5.5