From mboxrd@z Thu Jan 1 00:00:00 1970 From: hejianet Subject: Re: [RFC PATCH v3 3/7] proc: Reduce cache miss in snmp6_seq_show Date: Wed, 14 Sep 2016 11:11:10 +0800 Message-ID: <592fd271-780e-8d35-891b-0fae676b971a@gmail.com> References: <1473402842-1987-1-git-send-email-hejianet@gmail.com> <1473402842-1987-4-git-send-email-hejianet@gmail.com> <20160912190502.GC17689@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, 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 To: Marcelo Return-path: In-Reply-To: <20160912190502.GC17689@localhost.localdomain> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On 9/13/16 3:05 AM, Marcelo wrote: > On Fri, Sep 09, 2016 at 02:33:58PM +0800, Jia He wrote: >> 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 >> --- >> net/ipv6/proc.c | 32 +++++++++++++++++++++++--------- >> 1 file changed, 23 insertions(+), 9 deletions(-) >> >> diff --git a/net/ipv6/proc.c b/net/ipv6/proc.c >> index 679253d0..50ba2c3 100644 >> --- a/net/ipv6/proc.c >> +++ b/net/ipv6/proc.c >> @@ -30,6 +30,11 @@ >> #include >> #include >> >> +#define MAX4(a, b, c, d) \ >> + max_t(u32, max_t(u32, a, b), max_t(u32, 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; >> @@ -192,13 +197,19 @@ static void snmp6_seq_show_item(struct seq_file *seq, void __percpu *pcpumib, >> 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); >> + unsigned long buff[SNMP_MIB_MAX]; >> + >> + memset(buff, 0, sizeof(unsigned long) * SNMP_MIB_MAX); > This memset() could be moved... > >> + >> + if (pcpumib) { > ... here, so it's not executed if it hits the else block. Thanks for the suggestion B.R. Jia >> + snmp_get_cpu_field_batch(buff, itemlist, pcpumib); >> + 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)); >> } >> } >> >> @@ -206,10 +217,13 @@ static void snmp6_seq_show_item64(struct seq_file *seq, void __percpu *mib, >> const struct snmp_mib *itemlist, size_t syncpoff) >> { >> int i; >> + u64 buff64[SNMP_MIB_MAX]; >> + >> + memset(buff64, 0, sizeof(unsigned long) * SNMP_MIB_MAX); >> >> + snmp_get_cpu_field64_batch(buff64, itemlist, mib, 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, buff64[i]); >> } >> >> static int snmp6_seq_show(struct seq_file *seq, void *v) >> -- >> 1.8.3.1 >> >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-sctp" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html >>