--- /dev/null
+/*
+ * Copyright (c) 2013-2014 Apple Inc. All rights reserved.
+ *
+ * @APPLE_LICENSE_HEADER_START@
+ *
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this
+ * file.
+ *
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
+ * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
+ *
+ * @APPLE_LICENSE_HEADER_END@
+ */
+
+#ifndef _SYS_QOS_H
+#define _SYS_QOS_H
+
+#include <sys/cdefs.h>
+#include <Availability.h>
+
+/*!
+ * @typedef qos_class_t
+ *
+ * @abstract
+ * An abstract thread quality of service (QOS) classification.
+ *
+ * @discussion
+ * Thread quality of service (QOS) classes are ordered abstract representations
+ * of the nature of work that is expected to be performed by a pthread, dispatch
+ * queue, or NSOperation. Each class specifies a maximum thread scheduling
+ * priority for that band (which may be used in combination with a relative
+ * priority offset within the band), as well as quality of service
+ * characteristics for timer latency, CPU throughput, I/O throughput, network
+ * socket traffic management behavior and more.
+ *
+ * A best effort is made to allocate available system resources to every QOS
+ * class. Quality of service degredation only occurs during system resource
+ * contention, proportionally to the QOS class. That said, QOS classes
+ * representing user-initiated work attempt to achieve peak throughput while
+ * QOS classes for other work attempt to achieve peak energy and thermal
+ * efficiency, even in the absence of contention. Finally, the use of QOS
+ * classes does not allow threads to supersede any limits that may be applied
+ * to the overall process.
+ */
+
+/*!
+ * @constant QOS_CLASS_USER_INTERACTIVE
+ * @abstract A QOS class which indicates work performed by this thread
+ * is interactive with the user.
+ * @discussion Such work is requested to run at high priority relative to other
+ * work on the system. Specifying this QOS class is a request to run with
+ * nearly all available system CPU and I/O bandwidth even under contention.
+ * This is not an energy-efficient QOS class to use for large tasks. The use of
+ * this QOS class should be limited to critical interaction with the user such
+ * as handling events on the main event loop, view drawing, animation, etc.
+ *
+ * @constant QOS_CLASS_USER_INITIATED
+ * @abstract A QOS class which indicates work performed by this thread
+ * was initiated by the user and that the user is likely waiting for the
+ * results.
+ * @discussion Such work is requested to run at a priority below critical user-
+ * interactive work, but relatively higher than other work on the system. This
+ * is not an energy-efficient QOS class to use for large tasks. Its use
+ * should be limited to operations of short enough duration that the user is
+ * unlikely to switch tasks while waiting for the results. Typical
+ * user-initiated work will have progress indicated by the display of
+ * placeholder content or modal user interface.
+ *
+ * @constant QOS_CLASS_DEFAULT
+ * @abstract A default QOS class used by the system in cases where more specific
+ * QOS class information is not available.
+ * @discussion Such work is requested to run at a priority below critical user-
+ * interactive and user-initiated work, but relatively higher than utility and
+ * background tasks. Threads created by pthread_create() without an attribute
+ * specifying a QOS class will default to QOS_CLASS_DEFAULT. This QOS class
+ * value is not intended to be used as a work classification, it should only be
+ * set when propagating or restoring QOS class values provided by the system.
+ *
+ * @constant QOS_CLASS_UTILITY
+ * @abstract A QOS class which indicates work performed by this thread
+ * may or may not be initiated by the user and that the user is unlikely to be
+ * immediately waiting for the results.
+ * @discussion Such work is requested to run at a priority below critical user-
+ * interactive and user-initiated work, but relatively higher than low-level
+ * system maintenance tasks. The use of this QOS class indicates the work
+ * should be run in an energy and thermally-efficient manner. The progress of
+ * utility work may or may not be indicated to the user, but the effect of such
+ * work is user-visible.
+ *
+ * @constant QOS_CLASS_BACKGROUND
+ * @abstract A QOS class which indicates work performed by this thread was not
+ * initiated by the user and that the user may be unaware of the results.
+ * @discussion Such work is requested to run at a priority below other work.
+ * The use of this QOS class indicates the work should be run in the most energy
+ * and thermally-efficient manner.
+ *
+ * @constant QOS_CLASS_UNSPECIFIED
+ * @abstract A QOS class value which indicates the absence or removal of QOS
+ * class information.
+ * @discussion As an API return value, may indicate that threads or pthread
+ * attributes were configured with legacy API incompatible or in conflict with
+ * the QOS class system.
+ */
+
+#define __QOS_ENUM(name, type, ...) enum { __VA_ARGS__ }; typedef type name##_t
+#define __QOS_CLASS_AVAILABLE(...)
+
+#if defined(__cplusplus) || defined(__OBJC__) || __LP64__
+#if defined(__has_feature) && defined(__has_extension)
+#if __has_feature(objc_fixed_enum) || __has_extension(cxx_strong_enums)
+#undef __QOS_ENUM
+#define __QOS_ENUM(name, type, ...) typedef enum : type { __VA_ARGS__ } name##_t
+#endif
+#endif
+#if __has_feature(enumerator_attributes)
+#undef __QOS_CLASS_AVAILABLE
+#define __QOS_CLASS_AVAILABLE __API_AVAILABLE
+#endif
+#endif
+
+__QOS_ENUM(qos_class, unsigned int,
+ QOS_CLASS_USER_INTERACTIVE
+ __QOS_CLASS_AVAILABLE(macos(10.10), ios(8.0)) = 0x21,
+ QOS_CLASS_USER_INITIATED
+ __QOS_CLASS_AVAILABLE(macos(10.10), ios(8.0)) = 0x19,
+ QOS_CLASS_DEFAULT
+ __QOS_CLASS_AVAILABLE(macos(10.10), ios(8.0)) = 0x15,
+ QOS_CLASS_UTILITY
+ __QOS_CLASS_AVAILABLE(macos(10.10), ios(8.0)) = 0x11,
+ QOS_CLASS_BACKGROUND
+ __QOS_CLASS_AVAILABLE(macos(10.10), ios(8.0)) = 0x09,
+ QOS_CLASS_UNSPECIFIED
+ __QOS_CLASS_AVAILABLE(macos(10.10), ios(8.0)) = 0x00,
+);
+
+#undef __QOS_ENUM
+
+/*!
+ * @constant QOS_MIN_RELATIVE_PRIORITY
+ * @abstract The minimum relative priority that may be specified within a
+ * QOS class. These priorities are relative only within a given QOS class
+ * and meaningful only for the current process.
+ */
+#define QOS_MIN_RELATIVE_PRIORITY (-15)
+
+/* Userspace (only) definitions */
+
+#ifndef KERNEL
+
+__BEGIN_DECLS
+
+/*!
+ * @function qos_class_self
+ *
+ * @abstract
+ * Returns the requested QOS class of the current thread.
+ *
+ * @return
+ * One of the QOS class values in qos_class_t.
+ */
+__API_AVAILABLE(macos(10.10), ios(8.0))
+qos_class_t
+qos_class_self(void);
+
+/*!
+ * @function qos_class_main
+ *
+ * @abstract
+ * Returns the initial requested QOS class of the main thread.
+ *
+ * @discussion
+ * The QOS class that the main thread of a process is created with depends on
+ * the type of process (e.g. application or daemon) and on how it has been
+ * launched.
+ *
+ * This function returns that initial requested QOS class value chosen by the
+ * system to enable propagation of that classification to matching work not
+ * executing on the main thread.
+ *
+ * @return
+ * One of the QOS class values in qos_class_t.
+ */
+__API_AVAILABLE(macos(10.10), ios(8.0))
+qos_class_t
+qos_class_main(void);
+
+__END_DECLS
+
+#endif // KERNEL
+
+#endif // _SYS_QOS_H
projects / apple / libpthread.git / blobdiff