commit 9bada8971173345ceb37ed1a47b00a01a4dd48cf
author Paolo Bonzini <pbonzini@redhat.com> Wed Nov 25 22:23:32 2015 +0100
committer Markus Armbruster <armbru@redhat.com> Thu Nov 26 10:07:07 2015 +0100
tree aa81d4f867c5eb59e4af390ef0c9d8da8f4c2131
parent 95385fe9ace7db156b924da6b6f5c9082b68ba68

qjson: surprise, allocating 6 QObjects per token is expensive

Replace the contents of the tokens GQueue with a simple struct.  This cuts
the amount of memory allocated by tests/check-qjson from ~500MB to ~20MB,
and the execution time from 600ms to 80ms on my laptop.  Still a lot (some
could be saved by using an intrusive list, such as QSIMPLEQ, instead of
the GQueue), but the savings are already massive and the right thing to
do would probably be to get rid of json-streamer completely.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <1448300659-23559-5-git-send-email-pbonzini@redhat.com>
[Straightforwardly rebased on my patches]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>

qobject/json-streamer.c

diff --git a/qobject/json-streamer.c b/qobject/json-streamer.c
index f7a3e78..e87230d 100644
--- a/qobject/json-streamer.c
+++ b/qobject/json-streamer.c
@@ -11,10 +11,6 @@
  *
  */
 
-#include "qapi/qmp/qlist.h"
-#include "qapi/qmp/qstring.h"
-#include "qapi/qmp/qint.h"
-#include "qapi/qmp/qdict.h"
 #include "qemu-common.h"
 #include "qapi/qmp/json-lexer.h"
 #include "qapi/qmp/json-streamer.h"
@@ -34,7 +30,7 @@
                                        JSONTokenType type, int x, int y)
 {
     JSONMessageParser *parser = container_of(lexer, JSONMessageParser, lexer);
-    QDict *dict;
+    JSONToken *token;
 
     switch (type) {
     case JSON_LCURLY:
@@ -53,15 +49,16 @@
         break;
     }
 
-    dict = qdict_new();
-    qdict_put(dict, "type", qint_from_int(type));
-    qdict_put(dict, "token", qstring_from_str(input->str));
-    qdict_put(dict, "x", qint_from_int(x));
-    qdict_put(dict, "y", qint_from_int(y));
+    token = g_malloc(sizeof(JSONToken) + input->len + 1);
+    token->type = type;
+    memcpy(token->str, input->str, input->len);
+    token->str[input->len] = 0;
+    token->x = x;
+    token->y = y;
 
     parser->token_size += input->len;
 
-    g_queue_push_tail(parser->tokens, dict);
+    g_queue_push_tail(parser->tokens, token);
 
     if (type == JSON_ERROR) {
         goto out_emit_bad;