|author||Cory Benfield <email@example.com>||Mon Dec 04 17:06:49 2017 +0000|
|committer||Cory Benfield <firstname.lastname@example.org>||Mon Dec 04 17:06:49 2017 +0000|
Fully initialize ev.data. On Linux systems, ev.data is an 8-byte field, but this code currently initializes only 4 bytes of the field, leaving the trailing 4 bytes unininitialized. This causes memory safety tools like Valgrind to complain. This patch no longer explicitly initializes .data, ensuring that C structure initialization will force the .data field to be zero initialized. Manual checks of the compiled binary show that the compiler correctly initializes the 4 bytes for u32 only once, so this change incurs minimal overhead.
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