self-profile-events

The -Zself-profile-events compiler flag controls what events are recorded by the self-profiler when it is enabled via the -Zself-profile flag.

This flag takes a comma delimited list of event types to record.

For example:

$ rustc -Zself-profile -Zself-profile-events=default,args

Event types

  • query-provider

    • Traces each query used internally by the compiler.

  • generic-activity

    • Traces other parts of the compiler not covered by the query system.

  • query-cache-hit

    • Adds tracing information that records when the in-memory query cache is "hit" and does not need to re-execute a query which has been cached.
    • Disabled by default because this significantly increases the trace file size.

  • query-blocked

    • Tracks time that a query tries to run but is blocked waiting on another thread executing the same query to finish executing.
    • Query blocking only occurs when the compiler is built with parallel mode support.

  • incr-cache-load

    • Tracks time that is spent loading and deserializing query results from the incremental compilation on-disk cache.

  • query-keys

    • Adds a serialized representation of each query's query key to the tracing data.
    • Disabled by default because this significantly increases the trace file size.

  • function-args

    • Adds additional tracing data to some generic-activity events.
    • Disabled by default for parity with query-keys.

  • llvm

    • Adds tracing information about LLVM passes and codegeneration.
    • Disabled by default because this significantly increases the trace file size.

Event synonyms

  • none

    • Disables all events. Equivalent to the self-profiler being disabled.

  • default

    • The default set of events which stikes a balance between providing detailed tracing data and adding additional overhead to the compilation.

  • args

    • Equivalent to query-keys and function-args.

  • all

    • Enables all events.

Examples

Enable the profiler and capture the default set of events (both invocations are equivalent):

$ rustc -Zself-profile
$ rustc -Zself-profile -Zself-profile-events=default

Enable the profiler and capture the default events and their arguments:

$ rustc -Zself-profile -Zself-profile-events=default,args