From 466577ba65c6c4aa9b14e6232e7d1dbed37511e7 Mon Sep 17 00:00:00 2001
From: Ruben Kerkhof <ruben@rubenkerkhof.com>
Date: Tue, 19 Feb 2019 11:58:26 +0100
Subject: [PATCH] Reduce the nr of allocations when parsing types.db

We allocate a number of times for each line in types.db.
Since plugin_register_dataset() makes a copy of the dataset anyway, we
can create the dataset on the stack instead of the heap.

This reduces the number of calloc calls on my system from 624 to 337
when running collectd -T with the default types.db.
---
 src/daemon/types_list.c | 30 +++++++++++-------------------
 1 file changed, 11 insertions(+), 19 deletions(-)

diff --git a/src/daemon/types_list.c b/src/daemon/types_list.c
index 9c610409..20df457a 100644
--- a/src/daemon/types_list.c
+++ b/src/daemon/types_list.c
@@ -96,8 +96,6 @@ static int parse_ds(data_source_t *dsrc, char *buf, size_t buf_len) {
 static void parse_line(char *buf) {
   char *fields[64];
   size_t fields_num;
-  data_set_t *ds;
-
   fields_num = strsplit(buf, fields, 64);
   if (fields_num < 2)
     return;
@@ -106,33 +104,27 @@ static void parse_line(char *buf) {
   if (fields[0][0] == '#')
     return;
 
-  ds = calloc(1, sizeof(*ds));
-  if (ds == NULL)
-    return;
+  data_set_t ds = {0};
 
-  sstrncpy(ds->type, fields[0], sizeof(ds->type));
+  sstrncpy(ds.type, fields[0], sizeof(ds.type));
 
-  ds->ds_num = fields_num - 1;
-  ds->ds = calloc(ds->ds_num, sizeof(*ds->ds));
-  if (ds->ds == NULL) {
-    sfree(ds);
+  ds.ds_num = fields_num - 1;
+  ds.ds = calloc(ds.ds_num, sizeof(*ds.ds));
+  if (ds.ds == NULL)
     return;
-  }
 
-  for (size_t i = 0; i < ds->ds_num; i++)
-    if (parse_ds(ds->ds + i, fields[i + 1], strlen(fields[i + 1])) != 0) {
+  for (size_t i = 0; i < ds.ds_num; i++)
+    if (parse_ds(ds.ds + i, fields[i + 1], strlen(fields[i + 1])) != 0) {
       ERROR("types_list: parse_line: Cannot parse data source #%" PRIsz
             " of data set %s",
-            i, ds->type);
-      sfree(ds->ds);
-      sfree(ds);
+            i, ds.type);
+      sfree(ds.ds);
       return;
     }
 
-  plugin_register_data_set(ds);
+  plugin_register_data_set(&ds);
 
-  sfree(ds->ds);
-  sfree(ds);
+  sfree(ds.ds);
 } /* void parse_line */
 
 static void parse_file(FILE *fh) {
-- 
2.11.0