commit b6ff2cd8c5bc1d4e4e61b9138436b507b31c6c7a
author Andrew Svetlov <andrew.svetlov@gmail.com> Sat Jun 15 14:55:52 2019 +0300
committer GitHub <noreply@github.com> Sat Jun 15 14:55:52 2019 +0300
tree 2345d189fd7c1676a13d0e0dbdea6a44c17c65f7
parent 68878140694faa8dc53daeb5d9fee4d60ed2b672

[3.8] Use threadpool for reading from file in sendfile fallback mode (GH-14076) (GH-14102)

(cherry picked from commit 0237265e8287141c40faa8719da3a2d21d511d0d)

Co-authored-by: Andrew Svetlov <andrew.svetlov@gmail.com>

Lib/asyncio/base_events.py

diff --git a/Lib/asyncio/base_events.py b/Lib/asyncio/base_events.py
index 90de858..14b80bd 100644
--- a/Lib/asyncio/base_events.py
+++ b/Lib/asyncio/base_events.py
@@ -1141,7 +1141,7 @@
                     if blocksize <= 0:
                         return total_sent
                 view = memoryview(buf)[:blocksize]
-                read = file.readinto(view)
+                read = await self.run_in_executor(None, file.readinto, view)
                 if not read:
                     return total_sent  # EOF
                 await proto.drain()