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625bb84bc4
scx_lavd tracks task state transitions and updates statistics on each valid transition. However, there's an asymmetry between the runnable/running and stopping/quiescent transitions. In the former, the runnable and running transitions are accounted separately in update_stat_for_enq() and update_stat_for_run(), respectively. However, in the latter, the two transitions are combined together in update_stat_for_stop(). This asymmetry leads to incorrect accounting. For example, a task's load should be added to the cpu's load sum when the task gets enqueued and subtracted when the task is no longer runnable (quiescent). The former is accounted correctly from update_stat_for_enq() but the latter is done whenever the task stops. A task can transit between running and stopping multiple times before becoming quiescent, so the asymmetry can end up subtracting the load of a task which is still running from the cpu's load sum. This patch: - introduces LAVD_TASK_STAT_QUIESCENT and updates transit_task_stat() so that it can handle all valid state transitions including the multiple back and forth transitions between two pairs - QUIESCENT <-> ENQ and RUNNING <-> STOPPING. - restores the symmetry by moving load adjustments part from update_stat_for_stop() to new update_stat_for_quiescent(). This removes a good chunk of ignored transitions. The next patch will take care of the rest. |
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| .. | ||
| scx_lavd | ||
| scx_layered | ||
| scx_rlfifo | ||
| scx_rustland | ||
| scx_rusty | ||
| meson.build | ||
| README.md | ||
RUST SCHEDULERS
Introduction
This directory contains schedulers with user space rust components.
The README in each scheduler directory provides some background and describes the types of workloads or scenarios they're designed to accommodate. For more details on any of these schedulers, please see the header comment in their main.rs or *.bpf.c files.