The benchmark was actually testing the speed of index lookups.
name old time/op new time/op delta
SaveAndEncrypt-8 101ns ± 2% 31505824ns ± 1% +31311591.31% (p=0.000 n=10+10)
name old speed new speed delta
SaveAndEncrypt-8 41.7TB/s ± 2% 0.0TB/s ± 1% -100.00% (p=0.000 n=10+10)
name old alloc/op new alloc/op delta
SaveAndEncrypt-8 1.00B ± 0% 20989508.40B ± 0% +2098950740.00% (p=0.000 n=10+10)
name old allocs/op new allocs/op delta
SaveAndEncrypt-8 0.00 123.00 ± 0% +Inf% (p=0.000 n=10+9)
(The actual speed is ca. 131MiB/s.)
A side remark to the definition of Index.blob:
Another possibility would have been to use:
blob map[restic.BlobHandle]*indexEntry
This would have led to the following sizes:
key: 32 + 1 = 33 bytes
value: 8 bytes
indexEntry: 8 + 4 + 4 = 16 bytes
each packID: 32 bytes
To save N index entries, we would therefore have needed:
N * OF * (33 + 8) bytes + N * 16 + N * 32 bytes / BP = N * 82 bytes
More precicely, using a pointer instead of a direct entry is the better memory choice if:
OF * 8 bytes + entrysize < OF * entrysize <=> entrysize > 8 bytes * OF/(OF-1)
Under the assumption of OF=1.5, this means using pointers would have been the better choice
if sizeof(indexEntry) > 24 bytes.
- The SaveBlob method now checks for duplicates.
- Moves handling of pending blobs to MasterIndex.
-> also cleans up pending index entries when they are saved in the index
-> when using SaveBlob no need to care about index any longer
- Always check for full index and save it when storing packs.
-> removes the need of an index uploader
-> also removes the verbose "uploaded intermediate index" messages
- The Flush method now also saves the index
- Fix race condition when checking and saving full/non-finalized indexes
When loading a blob, restic first looks up pack files containing the
blob. To avoid unnecessary work an already cached pack file is preferred.
However, if there is only a single pack file to choose from (which is
the normal case) sorting the one-element list won't change anything.
Therefore avoid the unnecessary cache check in that case.
The previous benchmark spent much of its time allocating RNGs and
generating too many random numbers. It now spends 90% of its time
hashing and half of the rest writing to files.
name old time/op new time/op delta
PackerManager-8 319ms ± 1% 247ms ± 1% -22.48% (p=0.000 n=20+18)
name old speed new speed delta
PackerManager-8 143MB/s ± 1% 213MB/s ± 1% +48.63% (p=0.000 n=10+18)
name old alloc/op new alloc/op delta
PackerManager-8 635kB ± 0% 92kB ± 0% -85.48% (p=0.000 n=10+19)
name old allocs/op new allocs/op delta
PackerManager-8 1.64k ± 0% 1.43k ± 0% -12.76% (p=0.000 n=10+20)
The pool was used improperly, causing more allocations to be
performed than without it.
name old time/op new time/op delta
SaveAndEncrypt-8 36.8ms ± 2% 36.9ms ± 2% ~ (p=0.218 n=10+10)
name old speed new speed delta
SaveAndEncrypt-8 114MB/s ± 2% 114MB/s ± 2% ~ (p=0.218 n=10+10)
name old alloc/op new alloc/op delta
SaveAndEncrypt-8 21.1MB ± 0% 21.0MB ± 0% -0.44% (p=0.000 n=10+10)
name old allocs/op new allocs/op delta
SaveAndEncrypt-8 79.0 ± 0% 77.0 ± 0% -2.53% (p=0.000 n=10+10)
I was running "golangci-lint" and found this two warnings
internal/checker/checker.go:135:18: (*Checker).LoadIndex$3 - result 0 (error) is always nil (unparam)
final := func() error {
^
internal/repository/repository.go:457:18: (*Repository).LoadIndex$3 - result 0 (error) is always nil (unparam)
final := func() error {
^
It turns out that these functions are used only in "RunWorkers(...)",
which is used only two times in whole project right after this "final"
functions.
And because these "final" functions always return "nil", I've
descided, that it would be better to remove requriments for "final" func
to return error to avoid magick "return nil" at their end.
Restic used to quit if the repository password was typed incorrectly once.
Restic will now ask the user again for the repository password if typed incorrectly.
The user will now get three tries to input the correct password before restic quits.
This commit changes the signatures for repository.LoadAndDecrypt and
utils.LoadAll to allow passing in a []byte as the buffer to use. This
buffer is enlarged as needed, and returned back to the caller for
further use.
In later commits, this allows reducing allocations by reusing a buffer
for multiple calls, e.g. in a worker function.
As mentioned in issue [#1560](https://github.com/restic/restic/pull/1560#issuecomment-364689346)
this changes the signature for `backend.Save()`. It now takes a
parameter of interface type `RewindReader`, so that the backend
implementations or our `RetryBackend` middleware can reset the reader to
the beginning and then retry an upload operation.
The `RewindReader` interface also provides a `Length()` method, which is
used in the backend to get the size of the data to be saved. This
removes several ugly hacks we had to do to pull the size back out of the
`io.Reader` passed to `Save()` before. In the `s3` and `rest` backend
this is actively used.
