Merge branch 'master' of ssh://git-annex.branchable.com

doc/bugs/importtree_spends_hours_reading_cidsdb/comment_11_a3fc6b67529ddce9e79c0e72996259ad._comment

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+[[!comment format=mdwn
+ username="jgoerzen"
+ avatar="http://cdn.libravatar.org/avatar/090740822c9dcdb39ffe506b890981b4"
+ subject="comment 11"
+ date="2023-06-02T21:44:53Z"
+ content="""
+So I ran your script on the same dataset that I was using.
+
+I was rather surprised that it rocketed through in 15 minutes.  I then ran a subsequent git annex sync, which after a few minutes started showing the same pread64 behavior as before.
+
+Perhaps your improvements have been helping here?
+
+I went back to my original full script and thought: let's time each git-annex call.
+
+```
+#!/bin/bash
+
+set -euo pipefail
+
+if [ -z \"$2\" ]; then
+        echo \"Syntax: $0 REPO DRIVE\"
+        exit 5
+fi
+
+REPO=\"$1\"
+DRIVE=\"$2\"
+DRIVEBASE=\"/acrypt/no-backup/jgoerzen/git-annex-testing\"
+
+set -x
+cd /acrypt/git-annex/repos
+mkdir $REPO
+cd $REPO
+git init
+git config annex.thin true
+git annex init 'local hub'
+# use newer belowgit annex wanted . \"include=mtree exclude=$REPO/*\"
+git annex wanted . \"include=* and exclude=$REPO/*\"
+
+# Now initialize things.
+touch mtree
+time git annex add mtree
+time git annex sync
+time git annex adjust --unlock-present
+
+time git annex initremote source type=directory directory=/acrypt/git-annex/bind-ro/$REPO importtree=yes encryption=none
+
+time git annex enableremote source directory=/acrypt/git-annex/bind-ro/$REPO
+git config remote.source.annex-readonly true
+git config remote.source.annex-tracking-branch main:$REPO # (says to put the files in the \"$REPO\" directory)
+git config annex.securehashesonly true
+git config annex.genmetadata true
+git config annex.diskreserve 100M
+
+time git annex sync
+
+# Now set up the clone
+
+cd $DRIVEBASE/$DRIVE/git-annex
+time git clone /acrypt/git-annex/repos/$REPO
+cd $REPO
+git config annex.thin true
+git annex init \"alexandria:Goerzen3\"
+time git annex adjust --unlock  # NTFS doesn't like symlinks
+time git annex sync
+
+cd /acrypt/git-annex/repos/$REPO
+git remote add $DRIVE $DRIVEBASE/$DRIVE/git-annex/$REPO
+time git annex sync $DRIVE
+git annex group $DRIVE archivedrive
+git annex wanted $DRIVE 'include=mtree* or standard' # 'standard and include=mtree*'
+time git annex sync
+
+cd $DRIVEBASE/$DRIVE/git-annex/$REPO
+time git annex sync
+git annex enableremote source directory=/acrypt/git-annex/bind-ro/$REPO
+git config remote.source.annex-readonly true
+git config remote.source.annex-tracking-branch main:$REPO # (says to put the files in the \"$REPO\" directory)
+git config annex.securehashesonly true
+git config annex.genmetadata true
+git config annex.diskreserve 100M
+
+time git annex sync --content
+time git annex get --auto
+
+cd /acrypt/git-annex/repos/$REPO
+time git annex sync
+```
+
+In this script:
+
+First sync (this is before the initremote so it is doing pretty much nothing):
+
+real    0m0.075s
+user    0m0.027s
+sys     0m0.045s
+
+Second sync (this is after initremote/enableremote):
+
+real    15m1.417s
+user    7m10.770s
+sys     5m59.405s
+
+[ that correlates closely with how long it took to run your script ]
+
+Third sync (this is after the clone/init/adjust):
+
+real    0m6.606s
+user    0m1.908s
+sys     0m4.632s
+
+Fourth sync (git annex sync $DRIVE):
+real    0m1.066s
+user    0m0.634s
+sys     0m0.647s
+
+Fifth sync (after the group/wanted):
+real    113m32.988s
+user    55m21.012s
+sys     58m40.752s
+
+Sixth sync:
+real    0m1.180s
+user    0m0.819s
+sys     0m0.514s
+
+Seventh sync (git annex sync --content):
+real    112m29.594s
+user    55m13.650s
+sys     57m52.259s
+
+Eigth sync (back at the original repo):
+real    110m3.099s
+user    51m32.468s
+sys     58m53.885s
+
+"""]]