Chrome Tracing format export for GPU profiling.

Export GPU profiling data in Chrome Tracing JSON format for visualization.

Usage Pattern:

1. Run profiled kernels and collect ProfileEvent list
2. Convert to Chrome Tracing JSON
3. Write to file
4. Open in chrome://tracing

Chrome Tracing Format: { "traceEvents": [ { "name": "kernel_name", "cat": "gpu", "ph": "X", "ts": 1234567.890, "dur": 123.456, "pid": 1, "tid": 1 } ], "displayTimeUnit": "ns" }

Where:

• name: Event name
• cat: Category (always "gpu")
• ph: Phase ("X" for complete events with duration)
• ts: Timestamp in microseconds (start time)
• dur: Duration in microseconds
• pid: Process ID (always 1)
• tid: Thread ID (always 1 for sequential GPU operations)

structure Hesper.Profile.Trace.ChromeTraceEvent : Type

A single event in Chrome Tracing format

• eventName : String
• eventCategory : String
• eventPhase : String
• eventTimestamp : Float
• eventDuration : Float
• eventPid : Nat
• eventTid : Nat

instance Hesper.Profile.Trace.instReprChromeTraceEvent : Repr ChromeTraceEvent

Equations

• Hesper.Profile.Trace.instReprChromeTraceEvent = { reprPrec := Hesper.Profile.Trace.instReprChromeTraceEvent.repr }

def Hesper.Profile.Trace.instReprChromeTraceEvent.repr : ChromeTraceEvent → Nat → Std.Format

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def Hesper.Profile.Trace.ChromeTraceEvent.toJSON (e : ChromeTraceEvent) : String

Convert to JSON object string

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structure Hesper.Profile.Trace.ChromeTrace : Type

Chrome Tracing document containing multiple events

• traceEvents : List ChromeTraceEvent
• displayTimeUnit : String

def Hesper.Profile.Trace.instReprChromeTrace.repr : ChromeTrace → Nat → Std.Format

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instance Hesper.Profile.Trace.instReprChromeTrace : Repr ChromeTrace

Equations

• Hesper.Profile.Trace.instReprChromeTrace = { reprPrec := Hesper.Profile.Trace.instReprChromeTrace.repr }

def Hesper.Profile.Trace.ChromeTrace.toJSON (t : ChromeTrace) : String

Convert to JSON string

Equations

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def Hesper.Profile.Trace.profileEventToTraceEvent (event : ProfileEvent) : ChromeTraceEvent

Convert a ProfileEvent to ChromeTraceEvent.

GPU timestamps are in nanoseconds, Chrome Tracing expects microseconds

Equations

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def Hesper.Profile.Trace.profileEventsToTrace (events : List ProfileEvent) : ChromeTrace

Convert list of ProfileEvents to ChromeTrace.

Events are sorted by start time for better visualization

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def Hesper.Profile.Trace.chromeTraceJSON (events : List ProfileEvent) : String

Generate Chrome Tracing JSON from ProfileEvents

Equations

• Hesper.Profile.Trace.chromeTraceJSON events = (Hesper.Profile.Trace.profileEventsToTrace events).toJSON

def Hesper.Profile.Trace.writeChromeTrace (filepath : String) (events : List ProfileEvent) : IO Unit

Write Chrome Tracing JSON to file.

The resulting file can be loaded in chrome://tracing for visualization.

Example: events <- runProfiledKernels writeChromeTrace "gpu_profile.json" events -- Then open chrome://tracing and load gpu_profile.json

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