Use time.perf_counter() instead of time.time() to measure performance

[simonw]

I do that in a bunch of places: https://ripgrep.datasette.io/-/ripgrep?pattern=time%28%29&literal=on&glob=datasette%2F%2A%2A

https://docs.python.org/3/library/time.html#time.perf_counter

time.``perf_counter() → float

Return the value (in fractional seconds) of a performance counter, i.e. a clock with the highest available resolution to measure a short duration. It does include time elapsed during sleep and is system-wide. The reference point of the returned value is undefined, so that only the difference between the results of consecutive calls is valid.

New in version 3.3.

[simonw]

Three places to fix:

datasette/datasette/tracer.py

Lines 40 to 42 in dcdfb2c

	start = time.time()
	yield
	end = time.time()

datasette/datasette/utils/__init__.py

Lines 139 to 152 in dcdfb2c

	@contextmanager
	def sqlite_timelimit(conn, ms):
	deadline = time.time() + (ms / 1000)
	# n is the number of SQLite virtual machine instructions that will be
	# executed between each check. It's hard to know what to pick here.
	# After some experimentation, I've decided to go with 1000 by default and
	# 1 for time limits that are less than 50ms
	n = 1000
	if ms < 50:
	n = 1
	def handler():
	if time.time() >= deadline:
	return 1

datasette/datasette/views/base.py

Lines 460 to 461 in dcdfb2c

	end = time.time()
	data["query_ms"] = (end - start) * 1000