# HG changeset patch
# User Pierre-Yves David <pierre-yves.david@octobus.net>
# Date 1711460045 0
# Node ID 6e4c8366c5ce836c17d841af2b1fb8215adedbad
# Parent  463e63aa547c48b8f891fcc9a1b3f00ceb376ee9
stream-clone: disable gc for the initial section for the v3 format

The number of small container created turn Python in a gc-frenzy that seriously
impact performance.

This significantly boost performance. The following number comes from a large
private repository using perf::stream-locked-section:

base-line:   35.04 seconds
prev-change: 24.51 seconds (-30%)
prev-change: 20.88 seconds (-40%)
this-change: 14.22 seconds (-60% from baseline; -31% from prev)

diff -r 463e63aa547c -r 6e4c8366c5ce mercurial/streamclone.py
--- a/mercurial/streamclone.py	Tue Mar 26 13:32:46 2024 +0000
+++ b/mercurial/streamclone.py	Tue Mar 26 13:34:05 2024 +0000
@@ -850,7 +850,10 @@
     - ways to adjust the number of expected entries/files ?
     """
 
-    with repo.lock():
+    # Python is getting crazy at all the small container we creates while
+    # considering the files to preserve, disabling the gc while we do so helps
+    # performance a lot.
+    with repo.lock(), util.nogc():
 
         repo.ui.debug(b'scanning\n')