| commit | 6af83dfd47369cf7aa4fd86973dd6c7fdcd32713 | [log] [tgz] |
|---|---|---|
| author | Corey Tabaka <eieio@google.com> | Thu Apr 25 09:00:11 2019 +0000 |
| committer | CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org> | Thu Apr 25 09:00:11 2019 +0000 |
| tree | 3a20d74b8dfe7730bcac391da59a03ae96da1004 | |
| parent | 1f889682b01c4442e3336ff81e8805c6741101b7 [diff] |
[kernel][sched] Tweak fair priority curve and preemption / latency.
- Switch to an exponential priority-to-weight curve to yield a ~65%
bandwidth increase to priority 24 (high priority) over priority 16
(default priority), and a constant ~10% difference between adjacent
priorities.
- Tweak the bandwidth adjustment to use the start of the current time
slice when changing the task rate so that preemptions happen faster
when high priority work is available.
- Adjust the target latency to provide a time slice more similar to the
previous scheduler when a high priority thread competes with lower
priority threads.
- Minor refactor to remove weight-to-priority conversions, which would
require a fixed-point logarithm to compute the inverse of the
exponential term.
- Optimize the priority-to-weight conversion using a constant table.
Bug: MTWN-269
Bug: ZX-3504
Test: Detailed tracing of synthetic workload; observe ratios of
bandwidth between priority 16 and priority 24 tasks.
Change-Id: I596c45cf3d8c94f93c986508f9ec1007624ac9f3
Pink + Purple == Fuchsia (a new operating system)
Fuchsia is a modular, capability-based operating system. Fuchsia runs on modern 64-bit Intel and ARM processors.
Fuchsia is an open source project with a code of conduct that we expect everyone who interacts with the project to respect.
See Getting Started.
See the documentation.