From: Frédéric Lécaille <flecaille@haproxy.com>
Date: Fri, 7 Jun 2019 12:25:25 +0000 (+0200)
Subject: MINOR: peers: Optimization for dictionary cache lookup.
X-Git-Tag: v2.0-dev7~24
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b65717fa55fe01e9972e7c809c775d948922a03c;p=thirdparty%2Fhaproxy.git

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 1b260e46c2..1d9123d1d8 100644
--- a/include/types/peers.h
+++ b/include/types/peers.h
@@ -102,6 +102,8 @@ struct dcache_tx {
 	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 7cc817cbc1..10fee312c1 100644
--- a/src/peers.c
+++ b/src/peers.c
@@ -2849,6 +2849,7 @@ static struct dcache_tx *new_dcache_tx(size_t max_entries)
 		goto err;
 
 	d->lru_key = 0;
+	d->prev_lookup = NULL;
 	d->cached_entries = EB_ROOT_UNIQUE;
 	d->entries = entries;
 
@@ -2948,7 +2949,17 @@ static struct ebpt_node *dcache_tx_insert(struct dcache *dc, struct dcache_tx_en
 	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 @@ static struct ebpt_node *dcache_tx_insert(struct dcache *dc, struct dcache_tx_en
 	}
 
 	/* 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;