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31 lines
1.6 KiB
Markdown
31 lines
1.6 KiB
Markdown
# scx_lavd
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This is a single user-defined scheduler used within [sched_ext](https://github.com/sched-ext/scx/tree/main), which is a Linux kernel feature which enables implementing kernel thread schedulers in BPF and dynamically loading them. [Read more about sched_ext](https://github.com/sched-ext/scx/tree/main).
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## Overview
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scx_lavd is a BPF scheduler that implements an LAVD (Latency-criticality Aware
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Virtual Deadline) scheduling algorithm. While LAVD is new and still evolving,
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its core ideas are 1) measuring how much a task is latency critical and 2)
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leveraging the task's latency-criticality information in making various
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scheduling decisions (e.g., task's deadline, time slice, etc.). As the name
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implies, LAVD is based on the foundation of deadline scheduling. This scheduler
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consists of the BPF part and the rust part. The BPF part makes all the
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scheduling decisions; the rust part loads the BPF code and conducts other
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chores (e.g., printing sampled scheduling decisions).
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## Typical Use Case
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scx_lavd is initially motivated by gaming workloads. It aims to improve
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interactivity and reduce stuttering while playing games on Linux. Hence, this
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scheduler's typical use case involves highly interactive applications, such as
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gaming, which requires high throughput and low tail latencies.
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## Production Ready?
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Yes, scx_lavd should be performant across various CPU architectures, but it
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mainly targets single CCX / single-socket systems. It creates a separate
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scheduling domain per-LLC, per-core type (e.g., P or E core on Intel, big or
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LITTLE on ARM), and per-NUMA domain, so the default balanced profile should be
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performant.
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