Crate measureme

This crate provides a library for high-performance event tracing which is used by the Rust compiler's unstable -Z self-profile feature.

The output of a tracing session will be three files:

1. A .events file which contains all of the traced events.
2. A .string_data file which contains all the strings referenced by events.
3. A .string_index file which maps StringId values to offsets into the .string_data file.

Writing event trace files

The main entry point for writing event trace files is the Profiler struct.

To create a Profiler, call the Profiler::new() function and provide a Path with the directory and file name for the trace files.

To record an event, call the Profiler::record_instant_event() method, passing a few arguments:

• event_kind: a StringId which assigns an arbitrary category to the event
• event_id: a StringId which specifies the name of the event
• thread_id: a u32 id of the thread which is recording this event

Alternatively, events can also be recorded via the Profiler::start_recording_interval_event() method. This method records a "start" event and returns a TimingGuard object that will automatically record the corresponding "end" event when it is dropped.

To create a StringId, call one of the string allocation methods:

• Profiler::alloc_string(): allocates a string and returns the StringId that refers to it
• Profiler::alloc_string_with_reserved_id(): allocates a string using the specified StringId. It is up to the caller to make sure the specified StringId hasn't already been used.

Re-exports

pub use crate::event_id::EventId;

pub use crate::event_id::EventIdBuilder;

pub use crate::stringtable::SerializableString;

pub use crate::stringtable::StringComponent;

pub use crate::stringtable::StringId;

pub use crate::stringtable::StringTableBuilder;

Modules

event_id
file_header	All binary files generated by measureme have a simple file header that consists of a 4 byte file magic string and a 4 byte little-endian version number.
rustc	This module contains functionality specific to to the measureme integration with rustc
stringtable	A string table implementation with a tree-like encoding.

Structs

Addr
ByteVecSink	A SerializationSink that writes to an internal Vec<u8> and can be converted into this raw Vec<u8>. This implementation is only meant to be used for testing and is not very efficient.
FileSerializationSink
MmapSerializationSink
Profiler
ProfilerFiles
RawEvent	RawEvent is how events are stored on-disk. If you change this struct, make sure that you increment file_header::CURRENT_FILE_FORMAT_VERSION.
TimingGuard	When dropped, this TimingGuard will record an "end" event in the Profiler it was created by.

Constants

MAX_INSTANT_TIMESTAMP	The max instant timestamp we can represent with the 48 bits available.
MAX_INTERVAL_TIMESTAMP	The max interval timestamp we can represent with the 48 bits available. The highest value is reserved for the INSTANT_TIMESTAMP_MARKER.

Traits

SerializationSink