commit | 930ff62792f5ea3be91270b2ac650d646dbd459b | [log] [tgz] |
---|---|---|
author | David Grove <groved@us.ibm.com> | Mon May 29 16:45:44 2017 -0400 |
committer | David Grove <groved@us.ibm.com> | Fri Jun 02 23:20:16 2017 -0400 |
tree | 7a0923a57a8b6204a5e17020898b6742c06f7eed | |
parent | acb1b1eb34e93a91d59c355def56fb2a8754f45c [diff] |
Convert dispatch_workq from legacy priorities to qos Update dispatch_workq (DISPATCH_USE_INTERNAL_WORKQUEUE) to use QoS-based constants instead of legacy priorities. Enhance monitoring code to count runnable threads from highest QoS to lowest and to suppress voluntary oversubscription for lower QoS queues if the total count of runnable worker threads is already over the desired threshold.
Grand Central Dispatch (GCD or libdispatch) provides comprehensive support for concurrent code execution on multicore hardware.
libdispatch is currently available on all Darwin platforms. This project aims to make a modern version of libdispatch available on all other Swift platforms. To do this, we will implement as much of the portable subset of the API as possible, using the existing open source C implementation.
libdispatch on Darwin is a combination of logic in the xnu
kernel alongside the user-space Library. The kernel has the most information available to balance workload across the entire system. As a first step, however, we believe it is useful to bring up the basic functionality of the library using user-space pthread primitives on Linux. Eventually, a Linux kernel module could be developed to support more informed thread scheduling.
A port of libdispatch to Linux has been completed. On Linux, since Swift 3, swift-corelibs-libdispatch has been included in all Swift releases and is used by other swift-corelibs projects.
Opportunities to contribute and on-going work include:
For detailed instructions on building and installing libdispatch, see INSTALL.md
For detailed instructions on testing libdispatch, see TESTING.md