From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755509AbcH2QEt (ORCPT ); Mon, 29 Aug 2016 12:04:49 -0400 Received: from mail-it0-f65.google.com ([209.85.214.65]:34945 "EHLO mail-it0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755308AbcH2QEq (ORCPT ); Mon, 29 Aug 2016 12:04:46 -0400 From: Jia He To: netdev@vger.kernel.org Cc: linux-sctp@vger.kernel.org, linux-kernel@vger.kernel.org, davem@davemloft.net, Alexey Kuznetsov , James Morris , Hideaki YOSHIFUJI , Patrick McHardy , Vlad Yasevich , Neil Horman , Steffen Klassert , Herbert Xu , Jia He Subject: [RFC PATCH 3/6] proc: Reduce cache miss in sctp_snmp_seq_show Date: Tue, 30 Aug 2016 00:03:57 +0800 Message-Id: <1472486640-1111-4-git-send-email-hejianet@gmail.com> X-Mailer: git-send-email 2.5.0 In-Reply-To: <1472486640-1111-1-git-send-email-hejianet@gmail.com> References: <1472486640-1111-1-git-send-email-hejianet@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This patch exchanges the two loop for collecting the percpu statistics data. This can reduce cache misses by going through all the items of each cpu sequentially. Signed-off-by: Jia He --- net/sctp/proc.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/net/sctp/proc.c b/net/sctp/proc.c index ef8ba77..085fb95 100644 --- a/net/sctp/proc.c +++ b/net/sctp/proc.c @@ -74,12 +74,19 @@ static const struct snmp_mib sctp_snmp_list[] = { static int sctp_snmp_seq_show(struct seq_file *seq, void *v) { struct net *net = seq->private; - int i; + int i, c; + unsigned long buff[SCTP_MIB_MAX]; + memset(buff, 0, sizeof(unsigned long) * SCTP_MIB_MAX); + + for_each_possible_cpu(c) + for (i = 0; sctp_snmp_list[i].name != NULL; i++) + buff[i] += snmp_get_cpu_field( + net->sctp.sctp_statistics, + c, sctp_snmp_list[i].entry); 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; } -- 1.8.3.1