[PATCH v3 2/3] winegstreamer: Use thread_count to determine 'max-threads' value.

[Brendan McGrath]

From: Brendan McGrath

GStreamer uses _SC_NPROCESSORS_CONF to determine 'max-threads'. On the
Steam Deck, this is configured to be 16 (which is double its number
of logical cores).

_SC_NPROCESSORS_CONF also disregards a process's CPU affinity, thus it
can create more threads than is useful, which ultimately wastes memory
resources.

Using thread_count to set 'max-threads' addresses both these problems.
---
 dlls/winegstreamer/unix_private.h |  3 +++
 dlls/winegstreamer/unixlib.c      | 17 +++++++++++++++++
 dlls/winegstreamer/wg_parser.c    |  7 +++++++
 dlls/winegstreamer/wg_transform.c |  2 ++
 4 files changed, 29 insertions(+)

diff --git a/dlls/winegstreamer/unix_private.h b/dlls/winegstreamer/unix_private.h
index 6f01b3a5a69..51b418eb513 100644
--- a/dlls/winegstreamer/unix_private.h
+++ b/dlls/winegstreamer/unix_private.h
@@ -31,6 +31,9 @@
 GST_DEBUG_CATEGORY_EXTERN(wine);
 #define GST_CAT_DEFAULT wine

+#define ELEMENT_HAS_PROPERTY(element, property) \
+     (!!g_object_class_find_property(G_OBJECT_CLASS(GST_ELEMENT_GET_CLASS((element))), (property)))
+
 extern NTSTATUS wg_init_gstreamer(void *args);

extern GstStreamType stream_type_from_caps(GstCaps *caps);
diff --git a/dlls/winegstreamer/unixlib.c b/dlls/winegstreamer/unixlib.c
index 354d723d5a3..9b069c1f310 100644
--- a/dlls/winegstreamer/unixlib.c
+++ b/dlls/winegstreamer/unixlib.c
@@ -302,3 +302,20 @@ NTSTATUS wg_init_gstreamer(void *arg)
             gst_version_string(), GST_VERSION_MAJOR, GST_VERSION_MINOR, GST_VERSION_MICRO);
     return STATUS_SUCCESS;
 }
+
+void set_max_threads(GstElement *element)
+{
+    const char *shortname = NULL;
+    GstElementFactory *factory = gst_element_get_factory(element);
+
+    if (factory)
+        shortname = gst_plugin_feature_get_name(GST_PLUGIN_FEATURE(factory));
+
+    if (shortname && strstr(shortname, "avdec_") && ELEMENT_HAS_PROPERTY(element, "max-threads"))
+    {
+        const gint32 MAX_THREADS = 16;
+        gint32 max_threads = MIN(thread_count, MAX_THREADS);
+        GST_DEBUG("%s found, setting max-threads to %d.", shortname, max_threads);
+        g_object_set(element, "max-threads", max_threads, NULL);
+    }
+}
diff --git a/dlls/winegstreamer/wg_parser.c b/dlls/winegstreamer/wg_parser.c
index 7253013b6a3..b4237731b29 100644
--- a/dlls/winegstreamer/wg_parser.c
+++ b/dlls/winegstreamer/wg_parser.c
@@ -567,6 +567,12 @@ static void no_more_pads_cb(GstElement *element, gpointer user)
     pthread_cond_signal(&parser->init_cond);
 }

+static void deep_element_added_cb(GstBin *self, GstBin *sub_bin, GstElement *element, gpointer user)
+{
+    if (element)
+        set_max_threads(element);
+}
+
 static gboolean sink_event_cb(GstPad *pad, GstObject *parent, GstEvent *event)
 {
     struct wg_parser_stream *stream = gst_pad_get_element_private(pad);
@@ -1797,6 +1803,7 @@ static BOOL decodebin_parser_init_gst(struct wg_parser *parser)
     g_signal_connect(element, "autoplug-continue", G_CALLBACK(autoplug_continue_cb), parser);
     g_signal_connect(element, "autoplug-select", G_CALLBACK(autoplug_select_cb), parser);
     g_signal_connect(element, "no-more-pads", G_CALLBACK(no_more_pads_cb), parser);
+    g_signal_connect(element, "deep-element-added", G_CALLBACK(deep_element_added_cb), parser);

pthread_mutex_lock(&parser->mutex);
     parser->no_more_pads = false;
diff --git a/dlls/winegstreamer/wg_transform.c b/dlls/winegstreamer/wg_transform.c
index 08c2c678024..1ca1906e6f6 100644
--- a/dlls/winegstreamer/wg_transform.c
+++ b/dlls/winegstreamer/wg_transform.c
@@ -486,6 +486,8 @@ NTSTATUS wg_transform_create(void *args)
             if (!(element = find_element(GST_ELEMENT_FACTORY_TYPE_DECODER, parsed_caps, sink_caps))
                     || !append_element(transform->container, element, &first, &last))
                 goto out;
+
+            set_max_threads(element);
             break;

case WG_MAJOR_TYPE_AUDIO: