The ETA restic displays was based on a rate computed across the entire
backup operation. Often restic can progress at uneven rates. In the worst
case, restic progresses over most of the backup at a very high rate and
then finds new data to back up. The displayed ETA is then unrealistic and
never adapts.
Restic now estimates the transfer rate based on a sliding window, with the
goal of adapting to observed changes in rate. To avoid wild changes in the
estimate, several heuristics are used to keep the sliding window wide
enough to be relatively stable.
This reverts commit f1c388c623fee735871067b912e6f5632f33f772.
For an uninitialized indexmap the returned size was `-1` which is
unexpected and could cause problems.
In order to change the backend initialization in `global.go` to be able
to generically call cfg.ApplyEnvironment() for supported backends, the
`interface{}` returned by `ParseConfig` must contain a pointer to the
configuration.
An alternative would be to use reflection to convert the type from
`interface{}(Config)` to `interface{}(*Config)` (from value to pointer
type). However, this would just complicate the type mess further.
The index used by restic consumes a major part of the total memory
usage. This leads to an unnecessarily large amount of memory that
contains ephemeral objects that are only used for a short time.
Modifies format module to add options for human readable storage size formatting, using size parsing already in ui/format.
Cmd flag --human-readable added to ls and find commands.
Additional option added to formatNode to support printing size in regular or new human readable format
Iterating through the indexmap according to the bucket order has the
problem that all indexEntries are accessed in random order which is
rather cache inefficient.
As we already keep a list of all allocated blocks, just iterate through
it. This allows iterating through a batch of indexEntries without random
memory accesses. In addition, the packID will likely remain similar
across multiple blobs as all blobs of a pack file are added as a single
batch.
This data structure reduces the wasted memory to O(sqrt(n)). The
top-layer of the hashed array tree (HAT) also has a size of O(sqrt(n)),
which makes it cache efficient. The top-layer should be small enough to
easily fit into the CPU cache and thus only adds little overhead
compared to directly accessing an index entry via a pointer.
The indexEntry objects are now allocated in a separate array. References
to an indexEntry are now stored as array indices. This has the benefit
of allowing the garbage collector to ignore the indexEntry objects as
these do not contain pointers and are part of a single large allocation.
New and its helpers used to create the cache directories several times
over. They now only do so once. The added test ensures that the cache is
produced in a consistent state when parts are deleted.
