Termy — A fast, native terminal

Performance and resource usage

Termy v0.2.18 is a focused performance prerelease that reduces CPU work, retained memory, render-cache overhead, and redundant engine wakeups.

Rendering and memory

Replaced inline shaped-line cache values with pointer-sized shared handles. Empty cache slots shrink from 2,984 bytes to 8 bytes while preserving row-cache reuse.

Release render-cache allocations for inactive tabs, hidden workspaces, and zoom snapshots so background terminals do not retain unnecessary shaped lines, draw operations, and color-cache capacity.

Avoid render timing instrumentation unless performance metrics are enabled.

Lazily initialize process metrics and clipboard reads so hidden diagnostics and unrelated terminal events do not pay for them.

CPU and engine work

Coalesce repeated PTY wakeups into one host signal until the queued event is drained, while preserving correct wakeups across hidden and visible transitions.

Transfer owned keyboard, paste, and mouse buffers directly into the native PTY path instead of copying them again.

Keep native terminal wakeup interest synchronized when switching tabs and workspaces.

Use GPUI's platform application entry point and remove the previous macOS thermal-observer workaround.

Performance diagnostics

Clarified that callback intervals measure idle/activity cadence, not frame latency. A roughly 500 ms callback interval can be healthy while the terminal is idle.

Added separate CPU-side view-build p50/p95/p99 measurements.

Relabeled memory reporting as process RSS so it is not confused with total GPU memory.

Tightened benchmark reporting for idle wakeups, cursor blinking, callback cadence, and displayed frames.

Measured results

Controlled local before/after benchmarks showed:

7.3% lower physical memory in a dense block-grid workload.

29.5% lower resident malloc memory in that workload.

About 5.8% lower CPU usage during steady scrolling.

About 6.2 MiB lower peak process memory during steady scrolling.

Effectively unchanged frame throughput.

Three repeated wakeup events collapse to one host wake signal until drained.

Validation

Full workspace test suite passed across all targets.

Strict workspace Clippy passed with warnings denied.

Release build and Intel macOS target checks passed.

Dependency policy, generated documentation, repository boundaries, formatting, and diff checks passed.

Both termy and termy_cli resolve and compile as version 0.2.18.

## Performance and resource usage Termy v0.2.18 is a focused performance prerelease that reduces CPU work, retained memory, render-cache overhead, and redundant engine wakeups. ### Rendering and memory - Replaced inline shaped-line cache values with pointer-sized shared handles. Empty cache slots shrink from 2,984 bytes to 8 bytes while preserving row-cache reuse. - Release render-cache allocations for inactive tabs, hidden workspaces, and zoom snapshots so background terminals do not retain unnecessary shaped lines, draw operations, and color-cache capacity. - Avoid render timing instrumentation unless performance metrics are enabled. - Lazily initialize process metrics and clipboard reads so hidden diagnostics and unrelated terminal events do not pay for them. ### CPU and engine work - Coalesce repeated PTY wakeups into one host signal until the queued event is drained, while preserving correct wakeups across hidden and visible transitions. - Transfer owned keyboard, paste, and mouse buffers directly into the native PTY path instead of copying them again. - Keep native terminal wakeup interest synchronized when switching tabs and workspaces. - Use GPUI's platform application entry point and remove the previous macOS thermal-observer workaround. ### Performance diagnostics - Clarified that callback intervals measure idle/activity cadence, not frame latency. A roughly 500 ms callback interval can be healthy while the terminal is idle. - Added separate CPU-side view-build p50/p95/p99 measurements. - Relabeled memory reporting as process RSS so it is not confused with total GPU memory. - Tightened benchmark reporting for idle wakeups, cursor blinking, callback cadence, and displayed frames. ### Measured results Controlled local before/after benchmarks showed: - 7.3% lower physical memory in a dense block-grid workload. - 29.5% lower resident malloc memory in that workload. - About 5.8% lower CPU usage during steady scrolling. - About 6.2 MiB lower peak process memory during steady scrolling. - Effectively unchanged frame throughput. - Three repeated wakeup events collapse to one host wake signal until drained. ### Validation - Full workspace test suite passed across all targets. - Strict workspace Clippy passed with warnings denied. - Release build and Intel macOS target checks passed. - Dependency policy, generated documentation, repository boundaries, formatting, and diff checks passed. - Both `termy` and `termy_cli` resolve and compile as version `0.2.18`.