Commit Graph

7 Commits

Author SHA1 Message Date
Michael Eischer 19afad8a09 restore: support sparse restores also on windows 2022-09-24 21:39:39 +02:00
Michael Eischer 34fe1362da restorer: move zeroPrefixLen to restic package 2022-09-24 21:39:39 +02:00
Michael Eischer 5b6a77058a Enable sparseness only conditionally
We can either preallocate storage for a file or sparsify it. This
detects a pack file as sparse if it contains an all zero block or
consists of only one block. As the file sparsification is just an
approximation, hide it behind a `--sparse` parameter.
2022-09-24 21:20:00 +02:00
greatroar 5d4568d393 Write sparse files in restorer
This writes files by using (*os.File).Truncate, which resolves to the
truncate system call on Unix.

Compared to the naive loop,

	for _, b := range p {
		if b != 0 {
			return false
		}
	}

the optimized allZero is about 10× faster:

name       old time/op    new time/op     delta
AllZero-8    1.09ms ± 1%     0.09ms ± 1%    -92.10%  (p=0.000 n=10+10)

name       old speed      new speed       delta
AllZero-8  3.84GB/s ± 1%  48.59GB/s ± 1%  +1166.51%  (p=0.000 n=10+10)
2022-09-24 21:18:48 +02:00
Michael Eischer c60540b196 add go:build headers everywhere 2022-03-28 22:23:47 +02:00
Michael Eischer 603bb0e309 restore: Use proper context while loading snapshot 2020-10-09 22:37:56 +02:00
Igor Fedorenko bda8d7722e restorer: Optimize empty file restore
don't create fileInfo structs for empty files. this saves memory.
this also avoids extra serial scan of all fileInfo, which should
make restore faster and more consistent.

Signed-off-by: Igor Fedorenko <igor@ifedorenko.com>
2018-10-14 17:39:42 +02:00