napari.utils.perf.PerfEvent

class napari.utils.perf.PerfEvent(name: str, start_ns: int, end_ns: int, category: str | None = None, process_id: int | None = None, thread_id: int | None = None, phase: str = 'X', **kwargs: float)

Bases: object

A performance related event: timer, counter, etc.

Parameters:

• name (str) – The name of this event like “draw”.

• start_ns (int) – Start time in nanoseconds.

• end_ns (int) – End time in nanoseconds.

• category (str) – Comma separated categories such has “render,update”.

• process_id (int) – The process id that produced the event.

• thread_id (int) – The thread id that produced the event.

• phase (str) – The Chrome Tracing “phase” such as “X”, “I”, “C”.

• **kwargs (dict) – Additional keyword arguments for the “args” field of the event.

name

The name of this event like “draw”.

Type:

str

span

The time span when the event happened.

Type:

Span

category

Comma separated categories such as “render,update”.

Type:

str

origin

The process and thread that produced the event.

Type:

Origin

args

Arbitrary keyword arguments for this event.

Type:

dict

phase

The Chrome Tracing phase (event type):

“X” - Complete Events “I” - Instant Events “C” - Counter Events

Type:

str

Notes

The time stamps are from perf_counter_ns() and do not indicate time of day. The origin is arbitrary, but subtracting two counters results in a valid span of wall clock time. If start is the same as the end the event was instant.

Google the phrase “Trace Event Format” for the full Chrome Tracing spec.

Methods

update_end_ns(end_ns)

Update our end_ns with this new end_ns.

Attributes

duration_ms	Duration in milliseconds.
duration_ns	Duration in nanoseconds.
duration_us	Duration in microseconds.
start_ms	Start time in milliseconds.
start_us	Start time in microseconds.

Details

property duration_ms: float

Duration in milliseconds.

property duration_ns: int

Duration in nanoseconds.

property duration_us: float

Duration in microseconds.

property start_ms: float

Start time in milliseconds.

property start_us: float

Start time in microseconds.

update_end_ns(end_ns: int) → None

Update our end_ns with this new end_ns.

end_ns

The new ending time in nanoseconds.

Type:

int