2 Commits

Author	SHA1	Message	Date
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