[RFC PATCH v2 3/6] proc: Reduce cache miss in sctp_snmp_seq_show
From: Jia He <hidden>
Date: 2016-09-06 02:30:42
Also in:
linux-sctp, lkml
Subsystem:
networking [general], sctp protocol, the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Marcelo Ricardo Leitner, Xin Long, Linus Torvalds
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 <redacted> --- 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