ip: speedup ip link
ip link has quadratic behavior because store_nlmsg()
has a head list pointer and search the end of list.
Provides a head/tail to cut time.
Time with 128000 net devices, to do "ip link show dev xxx"
Before: 2m3.594s
After: 0m2.830s
Signed-off-by: Eric Dumazet <edumazet@google.com>
diff --git a/ip/ipaddress.c b/ip/ipaddress.c
index 9ab65ec..1db7fd0 100644
--- a/ip/ipaddress.c
+++ b/ip/ipaddress.c
@@ -717,6 +717,12 @@
struct nlmsghdr h;
};
+struct nlmsg_chain
+{
+ struct nlmsg_list *head;
+ struct nlmsg_list *tail;
+};
+
static int print_selected_addrinfo(int ifindex, struct nlmsg_list *ainfo, FILE *fp)
{
for ( ;ainfo ; ainfo = ainfo->next) {
@@ -742,9 +748,8 @@
static int store_nlmsg(const struct sockaddr_nl *who, struct nlmsghdr *n,
void *arg)
{
- struct nlmsg_list **linfo = (struct nlmsg_list**)arg;
+ struct nlmsg_chain *lchain = (struct nlmsg_chain *)arg;
struct nlmsg_list *h;
- struct nlmsg_list **lp;
h = malloc(n->nlmsg_len+sizeof(void*));
if (h == NULL)
@@ -753,8 +758,11 @@
memcpy(&h->h, n, n->nlmsg_len);
h->next = NULL;
- for (lp = linfo; *lp; lp = &(*lp)->next) /* NOTHING */;
- *lp = h;
+ if (lchain->tail)
+ lchain->tail->next = h;
+ else
+ lchain->head = h;
+ lchain->tail = h;
ll_remember_index(who, n, NULL);
return 0;
@@ -762,8 +770,8 @@
static int ipaddr_list_or_flush(int argc, char **argv, int flush)
{
- struct nlmsg_list *linfo = NULL;
- struct nlmsg_list *ainfo = NULL;
+ struct nlmsg_chain linfo = { NULL, NULL};
+ struct nlmsg_chain ainfo = { NULL, NULL};
struct nlmsg_list *l, *n;
char *filter_dev = NULL;
int no_link = 0;
@@ -953,7 +961,7 @@
if (filter.family && filter.family != AF_PACKET) {
struct nlmsg_list **lp;
- lp=&linfo;
+ lp = &linfo.head;
if (filter.oneline)
no_link = 1;
@@ -963,7 +971,7 @@
struct ifinfomsg *ifi = NLMSG_DATA(&l->h);
struct nlmsg_list *a;
- for (a=ainfo; a; a=a->next) {
+ for (a = ainfo.head; a; a = a->next) {
struct nlmsghdr *n = &a->h;
struct ifaddrmsg *ifa = NLMSG_DATA(n);
@@ -1010,12 +1018,12 @@
}
}
- for (l=linfo; l; l = n) {
+ for (l = linfo.head; l; l = n) {
n = l->next;
if (no_link || print_linkinfo(NULL, &l->h, stdout) == 0) {
struct ifinfomsg *ifi = NLMSG_DATA(&l->h);
if (filter.family != AF_PACKET)
- print_selected_addrinfo(ifi->ifi_index, ainfo, stdout);
+ print_selected_addrinfo(ifi->ifi_index, ainfo.head, stdout);
}
fflush(stdout);
free(l);
