Use time.perf_counter() instead of time.time(), closes #1157

datasette/tracer.py

@@ -37,9 +37,9 @@ def trace(type, **kwargs):
     if tracer is None:
         yield
         return
-    start = time.time()
+    start = time.perf_counter()
     yield
-    end = time.time()
+    end = time.perf_counter()
     trace_info = {
         "type": type,
         "start": start,
@@ -74,7 +74,7 @@ class AsgiTracer:
         if b"_trace=1" not in scope.get("query_string", b"").split(b"&"):
             await self.app(scope, receive, send)
             return
-        trace_start = time.time()
+        trace_start = time.perf_counter()
         traces = []
 
         accumulated_body = b""
@@ -109,7 +109,7 @@ class AsgiTracer:
                 # We have all the body - modify it and send the result
                 # TODO: What to do about Content-Type or other cases?
                 trace_info = {
-                    "request_duration_ms": 1000 * (time.time() - trace_start),
+                    "request_duration_ms": 1000 * (time.perf_counter() - trace_start),
                     "sum_trace_duration_ms": sum(t["duration_ms"] for t in traces),
                     "num_traces": len(traces),
                     "traces": traces,

datasette/utils/__init__.py

@@ -138,7 +138,7 @@ class CustomJSONEncoder(json.JSONEncoder):
 
 @contextmanager
 def sqlite_timelimit(conn, ms):
-    deadline = time.time() + (ms / 1000)
+    deadline = time.perf_counter() + (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
@@ -148,7 +148,7 @@ def sqlite_timelimit(conn, ms):
         n = 1
 
     def handler():
-        if time.time() >= deadline:
+        if time.perf_counter() >= deadline:
             return 1
 
     conn.set_progress_handler(handler, n)

datasette/views/base.py

@@ -425,7 +425,7 @@ class DataView(BaseView):
             kwargs["default_labels"] = True
 
         extra_template_data = {}
-        start = time.time()
+        start = time.perf_counter()
         status_code = 200
         templates = []
         try:
@@ -457,7 +457,7 @@ class DataView(BaseView):
         except DatasetteError:
             raise
 
-        end = time.time()
+        end = time.perf_counter()
         data["query_ms"] = (end - start) * 1000
         for key in ("source", "source_url", "license", "license_url"):
             value = self.ds.metadata(key)