Improve performance with copy_file_range(2)#161
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sylvestre merged 2 commits intouutils:mainfrom Sep 30, 2025
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This is more realistic and allows to benchmark copy_file_range(2) performance.
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On file systems supporting reflinks or extent remapping, such
as XFS, Btrfs, NFS, regions of files that are not modified are
processed without any copying — with O(1) cost.
While at it:
- Correct the use of write(2) to handle partial writes and
report appropriate errors.
- Improve buffer sizing.
These are the benchmark results
no-op-short copy-file-range is 1.17 times faster than main
access-log-no-op copy-file-range is 2.91 times faster than main
access-log-no-subst copy-file-range is 1.56 times faster than main
access-log-subst copy-file-range is 1.03 times faster than main
access-log-no-del copy-file-range is 1.59 times faster than main
access-log-all-del copy-file-range is 1.06 times faster than main
access-log-translit copy-file-range is 1.05 times faster than main
access-log-complex-sub copy-file-range is 1.04 times faster than main
access-log-append copy-file-range is 1.05 times faster than main
remove-cr copy-file-range is 1.03 times faster than main
genome-subst copy-file-range is 1.08 times faster than main
number-fix copy-file-range is 1.03 times faster than main
long-script main is similarly fast as copy-file-range
hanoi main is 1.03 times faster than copy-file-range
factorial copy-file-range is 1.03 times faster than main
On suported file systems (XFS, BTRFS), output files with no or few in-place
modifications share large blocks with the input file, as can be seen
in the following example.
$ xfs_io -c 'fiemap -v' lines.txt
lines.txt:
EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS
0: [0..857199]: 11917304..12774503 857200 0x2000
1: [857200..857207]: 12774504..12774511 8 0x1
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ready for review ? :) |
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Author
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@sylvestre yes, ready, thanks! |
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