Support

System requirements

• macOS 14 (Sonoma) or later
• Apple Silicon or Intel Mac
• Trace files recorded on Linux with LTTng (CTF format recommended for all overlays)

Getting started

No Linux box handy? Download the trace-irq sample (zip) — scheduler, IRQ, and wakeup events (~180 KB).

1. Install Corelapse from the Mac App Store.
2. Record a trace on your Linux target with LTTng.
3. Copy the session folder to your Mac (scp, rsync, or shared folder).
4. In Corelapse, choose File → Open Trace… (⌘O).
5. Select the session root — the folder that contains kernel/ (and ust/ if you recorded userspace events).
6. Use the toolbar to toggle IRQ, Wakeup, Futex, and Mutex overlays (Full Access).

In-app recording recipes and navigation shortcuts are in Help → Corelapse Help (⌘?) inside the app.

What to record for each overlay

• Scheduler timeline (free) — kernel sched_switch
• Wakeups — kernel sched_wakeup
• IRQ bands — kernel irq_handler_entry, irq_handler_exit
• Futex bands — kernel --syscall futex
• Pthread mutex bands — UST lttng_ust_pthread:* with LD_PRELOAD=liblttng-ust-pthread-wrapper.so

Minimum scheduler-only recording:

sudo lttng create my-session
sudo lttng enable-event -k sched_switch
sudo lttng start
# … run workload …
sudo lttng stop
sudo lttng destroy my-session

Full Access (in-app purchase)

The free version includes the full per-CPU scheduler timeline, process filtering, navigation, and measurements. Full Access unlocks IRQ, wakeup, futex, and pthread mutex overlays with a one-time purchase.

• Restore purchases: open the upgrade sheet or Settings and tap Restore Purchases. You must be signed in with the same Apple ID used to buy Full Access.
• Refunds: handled by Apple. Request a refund through reportaproblem.apple.com.
• Testing purchases in Xcode: use a StoreKit Configuration file in the Run scheme (Edit Scheme → Run → Options).

Common issues

Empty IRQ / Futex / Mutex overlays
The trace may not include those events. Re-record with the matching LTTng events enabled (see in-app Help for full recipes). Babeltrace text dumps support scheduler viewing only; premium overlays require CTF.

Mutex overlay empty but futex shows activity
Kernel futex tracing and UST pthread mutex tracing are separate. Mutex bands need lttng-ust, the pthread wrapper, and an ust/ directory in the session.

“No sched_switch events found”
Open the CTF folder that contains scheduler events — usually the session root or its kernel/ subdirectory — not an unrelated folder.

Trace opens slowly or feels heavy
Large sessions with millions of events take time to parse. Filter to one process or TID, hide idle, and zoom to the time range you care about.

Scroll / zoom not working on the timeline
Use ⌘ or ⌥ + scroll to zoom, Shift + scroll to pan in time, and pinch on a trackpad. Plain scroll moves vertically across CPU lanes.

Reporting a bug

When contacting support, please include:

• macOS version and Corelapse version (Settings or About)
• What you expected vs. what happened
• How the trace was recorded (LTTng commands or recipe used)
• Whether the issue is with a specific overlay or the base timeline
• A small sample trace or anonymized screenshot if possible

Email info@corelapse.co or post in Discord.

Legal

Privacy Policy · LTTng is a project of EfficiOS; Corelapse is an independent trace viewer and is not affiliated with EfficiOS.