MINOR: peers: Optimization for dictionary cache lookup.
When we look up an dictionary entry in the cache used upon transmission
we store the last result in ->prev_lookup of struct dcache_tx so that
to compare it with the subsequent entries to look up and save performances.
diff --git a/include/types/peers.h b/include/types/peers.h
index 1b260e4..1d9123d 100644
--- a/include/types/peers.h
+++ b/include/types/peers.h
@@ -102,6 +102,8 @@
unsigned int lru_key;
/* An array of entries to store pointers to dictionary entries. */
struct ebpt_node *entries;
+ /* The previous lookup result. */
+ struct ebpt_node *prev_lookup;
/* ebtree to store the previous entries. */
struct eb_root cached_entries;
};
diff --git a/src/peers.c b/src/peers.c
index 7cc817c..10fee31 100644
--- a/src/peers.c
+++ b/src/peers.c
@@ -2849,6 +2849,7 @@
goto err;
d->lru_key = 0;
+ d->prev_lookup = NULL;
d->cached_entries = EB_ROOT_UNIQUE;
d->entries = entries;
@@ -2948,7 +2949,17 @@
struct ebpt_node *o;
dc_tx = dc->tx;
- o = dcache_tx_lookup_value(dc_tx, i);
+
+ if (dc_tx->prev_lookup && dc_tx->prev_lookup->key == i->entry.key) {
+ o = dc_tx->prev_lookup;
+ } else {
+ o = dcache_tx_lookup_value(dc_tx, i);
+ if (o) {
+ /* Save it */
+ dc_tx->prev_lookup = o;
+ }
+ }
+
if (o) {
/* Copy the ID. */
i->id = o - dc->tx->entries;
@@ -2956,7 +2967,7 @@
}
/* The new entry to put in cache */
- o = &dc_tx->entries[dc_tx->lru_key];
+ dc_tx->prev_lookup = o = &dc_tx->entries[dc_tx->lru_key];
ebpt_delete(o);
o->key = i->entry.key;