From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754940AbcIFCaf (ORCPT ); Mon, 5 Sep 2016 22:30:35 -0400 Received: from mail-it0-f66.google.com ([209.85.214.66]:35652 "EHLO mail-it0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754632AbcIFCab (ORCPT ); Mon, 5 Sep 2016 22:30:31 -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 v2 2/6] proc: Reduce cache miss in snmp6_seq_show Date: Tue, 6 Sep 2016 10:30:05 +0800 Message-Id: <1473129009-20478-3-git-send-email-hejianet@gmail.com> X-Mailer: git-send-email 2.5.0 In-Reply-To: <1473129009-20478-1-git-send-email-hejianet@gmail.com> References: <1473129009-20478-1-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/ipv6/proc.c | 47 ++++++++++++++++++++++++++++++++++++----------- 1 file changed, 36 insertions(+), 11 deletions(-) diff --git a/net/ipv6/proc.c b/net/ipv6/proc.c index 679253d0..c834646 100644 --- a/net/ipv6/proc.c +++ b/net/ipv6/proc.c @@ -30,6 +30,13 @@ #include #include +#define MAX(a, b) ((u32)(a) >= (u32)(b) ? (a) : (b)) + +#define MAX4(a, b, c, d) \ + MAX(MAX(a, b), MAX(c, d)) +#define SNMP_MIB_MAX MAX4(UDP_MIB_MAX, TCP_MIB_MAX, \ + IPSTATS_MIB_MAX, ICMP_MIB_MAX) + static int sockstat6_seq_show(struct seq_file *seq, void *v) { struct net *net = seq->private; @@ -191,25 +198,43 @@ static void snmp6_seq_show_item(struct seq_file *seq, void __percpu *pcpumib, atomic_long_t *smib, const struct snmp_mib *itemlist) { - int i; - unsigned long val; - - for (i = 0; itemlist[i].name; i++) { - val = pcpumib ? - snmp_fold_field(pcpumib, itemlist[i].entry) : - atomic_long_read(smib + itemlist[i].entry); - seq_printf(seq, "%-32s\t%lu\n", itemlist[i].name, val); + int i, c; + unsigned long buff[SNMP_MIB_MAX]; + + memset(buff, 0, sizeof(unsigned long) * SNMP_MIB_MAX); + + if (pcpumib) { + for_each_possible_cpu(c) + for (i = 0; itemlist[i].name; i++) + buff[i] += snmp_get_cpu_field(pcpumib, c, + itemlist[i].entry); + for (i = 0; itemlist[i].name; i++) + seq_printf(seq, "%-32s\t%lu\n", + itemlist[i].name, buff[i]); + } else { + for (i = 0; itemlist[i].name; i++) + seq_printf(seq, "%-32s\t%lu\n", itemlist[i].name, + atomic_long_read(smib + itemlist[i].entry)); } } static void snmp6_seq_show_item64(struct seq_file *seq, void __percpu *mib, const struct snmp_mib *itemlist, size_t syncpoff) { - int i; + int i, c; + u64 buff[SNMP_MIB_MAX]; + + memset(buff, 0, sizeof(unsigned long) * SNMP_MIB_MAX); + for_each_possible_cpu(c) { + for (i = 0; itemlist[i].name; i++) { + buff[i] += snmp_get_cpu_field64(mib, c, + itemlist[i].entry, + syncpoff); + } + } for (i = 0; itemlist[i].name; i++) - seq_printf(seq, "%-32s\t%llu\n", itemlist[i].name, - snmp_fold_field64(mib, itemlist[i].entry, syncpoff)); + seq_printf(seq, "%-32s\t%llu\n", itemlist[i].name, buff[i]); } static int snmp6_seq_show(struct seq_file *seq, void *v) -- 1.8.3.1