Merge remote-tracking branch 'remotes/mjt/tags/trivial-patches-fetch' into staging

[qemu.git] / iothread.c

diff --git a/iothread.c b/iothread.c
index 7bedde87e98fc61c1a2214145995fe8c542c60fa..beeb8705344071e9198510a3a99a1291e9a15523 100644 (file)
--- a/iothread.c
+++ b/iothread.c
@@ -30,6 +30,12 @@ typedef ObjectClass IOThreadClass;
 #define IOTHREAD_CLASS(klass) \
    OBJECT_CLASS_CHECK(IOThreadClass, klass, TYPE_IOTHREAD)
 
+/* Benchmark results from 2016 on NVMe SSD drives show max polling times around
+ * 16-32 microseconds yield IOPS improvements for both iodepth=1 and iodepth=32
+ * workloads.
+ */
+#define IOTHREAD_POLL_MAX_NS_DEFAULT 32768ULL
+
 static __thread IOThread *my_iothread;
 
 AioContext *qemu_get_current_aio_context(void)
@@ -71,6 +77,13 @@ static int iothread_stop(Object *object, void *opaque)
     return 0;
 }
 
+static void iothread_instance_init(Object *obj)
+{
+    IOThread *iothread = IOTHREAD(obj);
+
+    iothread->poll_max_ns = IOTHREAD_POLL_MAX_NS_DEFAULT;
+}
+
 static void iothread_instance_finalize(Object *obj)
 {
     IOThread *iothread = IOTHREAD(obj);
@@ -215,6 +228,7 @@ static const TypeInfo iothread_info = {
     .parent = TYPE_OBJECT,
     .class_init = iothread_class_init,
     .instance_size = sizeof(IOThread),
+    .instance_init = iothread_instance_init,
     .instance_finalize = iothread_instance_finalize,
     .interfaces = (InterfaceInfo[]) {
         {TYPE_USER_CREATABLE},
@@ -254,6 +268,9 @@ static int query_one_iothread(Object *object, void *opaque)
     info = g_new0(IOThreadInfo, 1);
     info->id = iothread_get_id(iothread);
     info->thread_id = iothread->thread_id;
+    info->poll_max_ns = iothread->poll_max_ns;
+    info->poll_grow = iothread->poll_grow;
+    info->poll_shrink = iothread->poll_shrink;
 
     elem = g_new0(IOThreadInfoList, 1);
     elem->value = info;