As the number of flows grows so does the length of time taken to update the
statistics of all facets. It has been obvserved that this becomes a performance
problem. This patch mitiages this effect by only dumping a limited number of
facets at a time.
Signed-off-by: Simon Horman <ho...@verge.net.au>
---
Since the last time that I tested this code (changest
279320b8276011df3667478de6750d5a40d0c6eb, "rhel: Add ability to enable bridge
compatibility mode in /etc/sysconfig/openvswitch") it seems that the cost of
dumping statistics has increased. I suspect that this relates to the
introducation of subfacet_find(). In any case I believe that a higher cost of
dumping stats makes a stronger case for the change introduced in this patch.
The previously posted version of this patch used a limit of 100,000 facets per
statistics dump. This revision uses a limit of 20,000 subfacets per dump.
Empirically these two revisions appear to exhibit the same performance.
---
ofproto/ofproto-dpif.c | 28 ++++++++++++++++++++++------
1 files changed, 22 insertions(+), 6 deletions(-)
diff --git a/ofproto/ofproto-dpif.c b/ofproto/ofproto-dpif.c
index ea5ed1e..e2a3939 100644
--- a/ofproto/ofproto-dpif.c
+++ b/ofproto/ofproto-dpif.c
@@ -345,6 +345,7 @@ struct subfacet {
/* Owners. */
struct hmap_node hmap_node; /* In struct ofproto_dpif 'subfacets' list. */
struct list list_node; /* In struct facet's 'facets' list. */
+ struct list may_expire; /* Potential expiry list. */
struct facet *facet; /* Owning facet. */
/* Key.
@@ -507,6 +508,7 @@ struct ofproto_dpif {
/* Facets. */
struct hmap facets;
struct hmap subfacets;
+ struct list expirable_subfacets;
/* Revalidation. */
struct table_dpif tables[N_TABLES];
@@ -659,6 +661,7 @@ construct(struct ofproto *ofproto_, int *n_tablesp)
hmap_init(&ofproto->facets);
hmap_init(&ofproto->subfacets);
+ list_init(&ofproto->expirable_subfacets);
for (i = 0; i < N_TABLES; i++) {
struct table_dpif *table = &ofproto->tables[i];
@@ -2916,12 +2919,18 @@ static void
update_stats(struct ofproto_dpif *p)
{
const struct dpif_flow_stats *stats;
- struct dpif_flow_dump dump;
+ static struct dpif_flow_dump dump;
const struct nlattr *key;
size_t key_len;
+ static bool complete = true;
+ int count = 20000;
- dpif_flow_dump_start(&dump, p->dpif);
- while (dpif_flow_dump_next(&dump, &key, &key_len, NULL, NULL, &stats)) {
+ if (complete) {
+ dpif_flow_dump_start(&dump, p->dpif);
+ complete = false;
+ }
+ while (--count &&
+ dpif_flow_dump_next(&dump, &key, &key_len, NULL, NULL, &stats)) {
struct subfacet *subfacet;
subfacet = subfacet_find(p, key, key_len);
@@ -2944,6 +2953,7 @@ update_stats(struct ofproto_dpif *p)
subfacet->dp_packet_count = stats->n_packets;
subfacet->dp_byte_count = stats->n_bytes;
+ list_insert(&p->expirable_subfacets, &subfacet->may_expire);
subfacet_update_time(subfacet, stats->used);
facet_account(facet);
facet_push_stats(facet);
@@ -2963,7 +2973,10 @@ update_stats(struct ofproto_dpif *p)
dpif_flow_del(p->dpif, key, key_len, NULL);
}
}
- dpif_flow_dump_done(&dump);
+ if (count) {
+ dpif_flow_dump_done(&dump);
+ complete = true;
+ }
}
/* Calculates and returns the number of milliseconds of idle time after which
@@ -3060,11 +3073,12 @@ expire_subfacets(struct ofproto_dpif *ofproto, int
dp_max_idle)
long long int cutoff = time_msec() - dp_max_idle;
struct subfacet *subfacet, *next_subfacet;
- HMAP_FOR_EACH_SAFE (subfacet, next_subfacet, hmap_node,
- &ofproto->subfacets) {
+ LIST_FOR_EACH_SAFE (subfacet, next_subfacet, may_expire,
+ &ofproto->expirable_subfacets) {
if (subfacet->used < cutoff) {
subfacet_destroy(subfacet);
}
+ list_remove(&subfacet->may_expire);
}
}
@@ -3739,6 +3753,7 @@ subfacet_create(struct facet *facet, enum odp_key_fitness
key_fitness,
subfacet = xzalloc(sizeof *subfacet);
hmap_insert(&ofproto->subfacets, &subfacet->hmap_node, key_hash);
list_push_back(&facet->subfacets, &subfacet->list_node);
+ list_init(&subfacet->may_expire);
subfacet->facet = facet;
subfacet->used = time_msec();
subfacet->key_fitness = key_fitness;
@@ -3780,6 +3795,7 @@ subfacet_destroy__(struct subfacet *subfacet)
subfacet_uninstall(subfacet);
hmap_remove(&ofproto->subfacets, &subfacet->hmap_node);
+ list_remove(&subfacet->may_expire);
list_remove(&subfacet->list_node);
free(subfacet->key);
free(subfacet->actions);
--
1.7.4.1
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