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.
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.
This does not change the overall license of the git-annex program, which
was already AGPL due to a number of sources files being AGPL already.
Legally speaking, I'm adding a new license under which these files are
now available; I already released their current contents under the GPL
license. Now they're dual licensed GPL and AGPL. However, I intend
for all my future changes to these files to only be released under the
AGPL license, and I won't be tracking the dual licensing status, so I'm
simply changing the license statement to say it's AGPL.
(In some cases, others wrote parts of the code of a file and released it
under the GPL; but in all cases I have contributed a significant portion
of the code in each file and it's that code that is getting the AGPL
license; the GPL license of other contributors allows combining with
AGPL code.)
This reverts commit 4536c93bb2.
That broke Read/Show of a Key, and unfortunately Key is read in at least
one place; the GitAnnexDistribution data type.
It would be worth bringing this optimisation back, but it would need
either a custom Read/Show instance that preserves back-compat, or
wrapping Key in a data type that contains the serialization, or changing
how GitAnnexDistribution is serialized.
Also, the Eq instance would need to compare keys with and without a
cached seralization the same.
It used to, but that was lost in the bytestring conversion recently.
20 * 4 = 80, but I only increased it to 64, which would be up to 16
4-byte unicode characters.
The builder produces a lazy ByteString, and L.toStrict has to copy it,
but needing to use the builder is no longer to common case; the
serialization will normally be cached already as a strict ByteString,
and this avoids keyFile' needing to use L.toStrict . serializeKey'
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.
It means that every place a Key has any of its fields changed, the cache
has to be dropped. I've grepped and found them all. But, it would be
better to avoid that gotcha somehow..
What these generate is not really suitable to be used as a filename,
which is why keyFile and fileKey further escape it. These are just
serializing Keys.
Also removed a quickcheck test that was very unlikely to test anything
useful, since it relied on random chance creating something that looks
like a serialized key. The other test is sufficient for testing what
that was intended to test anyway.
The new parser is significantly stricter than the old one:
The old file2key allowed the fields to come in any order,
but the new one requires the fixed order that git-annex has always used.
Hopefully this will not cause any breakage.
And the old file2key allowed eg SHA1-m1-m2-m3-m4-m5-m6--xxxx
while the new does not allow duplication of fields. This could potentially
improve security, because allowing lots of extra junk like that in a key
could potentially be used in a SHA1 collision attack, although the current
attacks need binary data and not this kind of structured numeric data.
Speed improved of course, and fairly substantially, in microbenchmarks:
benchmarking old/key2file
time 2.264 μs (2.257 μs .. 2.273 μs)
1.000 R² (1.000 R² .. 1.000 R²)
mean 2.265 μs (2.260 μs .. 2.275 μs)
std dev 21.17 ns (13.06 ns .. 39.26 ns)
benchmarking new/key2file'
time 1.744 μs (1.741 μs .. 1.747 μs)
1.000 R² (1.000 R² .. 1.000 R²)
mean 1.745 μs (1.742 μs .. 1.751 μs)
std dev 13.55 ns (9.099 ns .. 21.89 ns)
benchmarking old/file2key
time 6.114 μs (6.102 μs .. 6.129 μs)
1.000 R² (1.000 R² .. 1.000 R²)
mean 6.118 μs (6.106 μs .. 6.143 μs)
std dev 55.00 ns (30.08 ns .. 100.2 ns)
benchmarking new/file2key'
time 1.791 μs (1.782 μs .. 1.801 μs)
1.000 R² (0.999 R² .. 1.000 R²)
mean 1.792 μs (1.785 μs .. 1.804 μs)
std dev 32.46 ns (20.59 ns .. 50.82 ns)
variance introduced by outliers: 19% (moderately inflated)
As long as all code imports Utility.Aeson rather than Data.Aeson,
and no Strings that may contain utf-8 characters are used for eg, object
keys via T.pack, this is guaranteed to fix the problem everywhere that
git-annex generates json.
It's kind of annoying to need to wrap ToJSON with a ToJSON', especially
since every data type that has a ToJSON instance has to be ported over.
However, that only took 50 lines of code, which is worth it to ensure full
coverage. I initially tried an alternative approach of a newtype FileEncoded,
which had to be used everywhere a String was fed into aeson, and chasing
down all the sites would have been far too hard. Did consider creating an
intentionally overlapping instance ToJSON String, and letting ghc fail
to build anything that passed in a String, but am not sure that wouldn't
pollute some library that git-annex depends on that happens to use ToJSON
String internally.
This commit was supported by the NSF-funded DataLad project.
QuickCheck added an Arbitrary instance for CTime aka EpochTime. However,
while git-annex's instance disallowed times before the epoch, QuickCheck's
does not. So, rather than using its instance, convert from an Integer.
This commit was sponsored by Thomas Hochstein on Patreon.
Yesterday's SHA1 collision attack could be used to generate eg:
SHA256-sfoo--whatever.good
SHA256-sfoo--whatever.bad
Such that they collide. A repository with the good one could have the
bad one swapped in and signed commits would still verify.
I've already mitigated this.
Where before the "name" of a key and a backend was a string, this makes
it a concrete data type.
This is groundwork for allowing some varieties of keys to be disabled
in file2key, so git-annex won't use them at all.
Benchmarks ran in my big repo:
old git-annex info:
real 0m3.338s
user 0m3.124s
sys 0m0.244s
new git-annex info:
real 0m3.216s
user 0m3.024s
sys 0m0.220s
new git-annex find:
real 0m7.138s
user 0m6.924s
sys 0m0.252s
old git-annex find:
real 0m7.433s
user 0m7.240s
sys 0m0.232s
Surprising result; I'd have expected it to be slower since it now parses
all the key varieties. But, the parser is very simple and perhaps
sharing KeyVarieties uses less memory or something like that.
This commit was supported by the NSF-funded DataLad project.
It compiles. It sorta works. Several subcommands are FIXME marked and
broken, because things that used to accept separate --backend and --key
params need to be changed to accept just a --key that encodes all the key
info, now that there is metadata in keys.
