The parser and looking up config keys in the map should both be faster
due to using ByteString.
I had hoped this would speed up startup time, but any improvement to
that was too small to measure. Seems worth keeping though.
Note that the parser breaks up the ByteString, but a config map ends up
pointing to the config as read, which is retained in memory until every
value from it is no longer used. This can change memory usage
patterns marginally, but won't affect git-annex.
While L.toStrict copies, profiling showed it was only around 0.3% of
git-annex find runtime. Does not seem worth optimising that, which would
probably involve either a major refactoring, or a use of
UnsafeInterleaveIO.
Also, it seems to me that the latter would need to read chunks, and
preappend the leftover part to the next chunk. But a strict ByteString
append itself is a copy, so I'm not convinced that would be faster than
L.toStrict.
Finally builds (oh the agoncy of making it build), but still very
unmergable, only Command.Find is included and lots of stuff is badly
hacked to make it compile.
Benchmarking vs master, this git-annex find is significantly faster!
Specifically:
num files old new speedup
48500 4.77 3.73 28%
12500 1.36 1.02 66%
20 0.075 0.074 0% (so startup time is unchanged)
That's without really finishing the optimization. Things still to do:
* Eliminate all the fromRawFilePath, toRawFilePath, encodeBS,
decodeBS conversions.
* Use versions of IO actions like getFileStatus that take a RawFilePath.
* Eliminate some Data.ByteString.Lazy.toStrict, which is a slow copy.
* Use ByteString for parsing git config to speed up startup.
It's likely several of those will speed up git-annex find further.
And other commands will certianly benefit even more.
Goal is to make git-annex faster by using ByteString for all the
worktree traversal. For now, this is focusing on Command.Find,
in order to benchmark how much it helps. (All other commands are
temporarily disabled)
Currently in a very bad unbuildable in-between state.
This will speed up the common case where a Key is deserialized from
disk, but is then serialized to build eg, the path to the annex object.
Previously attempted in 4536c93bb2
and reverted in 96aba8eff7.
The problems mentioned in the latter commit are addressed now:
Read/Show of KeyData is backwards-compatible with Read/Show of Key from before
this change, so Types.Distribution will keep working.
The Eq instance is fixed.
Also, Key has smart constructors, avoiding needing to remember to update
the cached serialization.
Used git-annex benchmark:
find is 7% faster
whereis is 3% faster
get when all files are already present is 5% faster
Generally, the benchmarks are running 0.1 seconds faster per 2000 files,
on a ram disk in my laptop.
Note from Joey:
git-annex still supports git 2.1, but operates in a degraded fashion.
It would be better for backports of the debian package to also
backport a newer git. This dependency is mostly expressing that,
also that any users who might upgrade git-annex should also upgrade
git.
Also worth noting that the i386ancient autobuilder has git 2.1 on it
(best I have been able to manage there), but luckily the epoch is
bumped to 2, so the dependencies will still be satisfied.
Used to work but was broken in version 7.20181031, specifically commit
5ab0f48ffb.
That this was not noticed over at least 1 daylight savings time zone
changes makes me wonder if the TSDelta stuff is still needed.
Perhaps the mtime on Windows no longer changes when the time zone is changed?
(cherry picked from commit 09ee6b0ccb)
* benchmark: Changed --databases to take a parameter specifiying the size
of the database to benchmark.
* benchmark --databases: Display size of the populated database.
* benchmark --databases: Improve the "addAssociatedFile to (new)"
benchmark to really add new values, not overwriting old values.
Eliminated some dead code. In other cases, exported a currently unused
function, since it was a logical part of the API.
Of course this improves the API documentation. It may also sometimes
let ghc optimize code better, since it can know a function is internal
to a module.
364 modules still to go, according to
git grep -E 'module [A-Za-z.]+ where'
It's not necessary. And if the bare repo somehow has a pointer
file in it with the same name as a file in HEAD, that file would be
populated, which would be surprising since the file is not really under
git's control.
