netdev - [PATCH v6 4/7] proc: Reduce cache miss in sctp_snmp_seq

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Message-Id: <1475206144-23228-5-git-send-email-hejianet@gmail.com>
Date:   Fri, 30 Sep 2016 11:29:01 +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 v6 4/7] proc: Reduce cache miss in sctp_snmp_seq_show

This is to use the generic interfaces 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/sctp/proc.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/net/sctp/proc.c b/net/sctp/proc.c
index ef8ba77..09e16c2 100644
--- a/net/sctp/proc.c
+++ b/net/sctp/proc.c
@@ -73,13 +73,17 @@ static const struct snmp_mib sctp_snmp_list[] = {
 /* Display sctp snmp mib statistics(/proc/net/sctp/snmp). */
 static int sctp_snmp_seq_show(struct seq_file *seq, void *v)
 {
+	unsigned long buff[SCTP_MIB_MAX];
 	struct net *net = seq->private;
 	int i;
 
+	memset(buff, 0, sizeof(unsigned long) * SCTP_MIB_MAX);
+
+	snmp_get_cpu_field_batch(buff, sctp_snmp_list,
+				 net->sctp.sctp_statistics);
 	for (i = 0; sctp_snmp_list[i].name != NULL; i++)
 		seq_printf(seq, "%-32s\t%ld\n", sctp_snmp_list[i].name,
-			   snmp_fold_field(net->sctp.sctp_statistics,
-				      sctp_snmp_list[i].entry));
+						buff[i]);
 
 	return 0;
 }
-- 
2.5.5