Nick Terrell [Mon, 13 Sep 2021 23:59:20 +0000 (16:59 -0700)]
[rsyncable] Ensure ZSTD_compressBound() is respected
In degenerate cases `--rsyncable` could create very small blocks (1
byte). This causes the compressed output to be larger than
`ZSTD_compressBound()`. Fix the issue by ensuring that rsyncable mode
never outputs blocks smaller than 128 KB.
The minimum job size is 512 KB, so we shouldn't lose many
synchronization points from skipping any that cause blocks smaller than
128 KB. And even if we do, that is fine, because we'll find the next
one.
This fixes the `raw_dictionary_round_trip` oss-fuzz assert.
This new setup is slighly better on `silesia.tar` :
Ratio : 3.649 -> 3.655
Speed : 11.9 MB/s -> 12.2 MB/s
At the cost of more memory : 24 MB -> 32 MB
The new memory budget is a reasonable interpolation between neighboring levels 12 and 14:
level 12 : 24 MB
level 13 : 32 MB (increased from 24 MB)
level 14 : 48 MB
Window size remains unaffected (4 MB)
W. Felix Handte [Thu, 26 Aug 2021 17:46:32 +0000 (13:46 -0400)]
Change Target Size in Fuzzer
It's a bit strange, because this is hitting the dictionary special case where
the dictionary is contiguous with the input and still runs in the single-
segment path.
We should probably change that to hit the `extDict` path instead?
W. Felix Handte [Thu, 26 Aug 2021 17:29:58 +0000 (13:29 -0400)]
Deduplicate Implementations
This removes the old `ZSTD_compressBlock_fast_generic()` and renames the new
`ZSTD_compressBlock_fast_generic_pipelined()` to replace it. This is
functionally a no-op.
W. Felix Handte [Fri, 20 Aug 2021 19:56:14 +0000 (15:56 -0400)]
Unroll Loop Core; Reduce Frequency of Repcode Check & Step Calc (+>1% Speed)
Unrolling the loop to handle 2 positions in each iteration allows us to reduce
the frequency of some operations that don't need to happen at every position.
One such operation is the step calculation, which is a very rough heuristic
anyways. It's fine if we do this a position later. The other operation is the
repcode check. But since the repcode check already tries expanding back one
position, we're really not missing much of importance by only trying it every
other position.
This commit also slightly reorders some operations.
W. Felix Handte [Wed, 18 Aug 2021 20:02:01 +0000 (16:02 -0400)]
Give Up on Searching End of Block
Amusingly, it seems to be a non-trivial performance hit to add in final
searches or even hash table insertions during cleanup. So let's not. It seems
to not make any meaningful difference in compression ratio.
Yann Collet [Sun, 29 Aug 2021 22:26:31 +0000 (15:26 -0700)]
reduce length of scanbuild static analyzer test
This was ~30mn, by far the longest run on travisCI.
That's because it re-analyzes multiple times the same files (library files notably).
It also performs actions that make no sense for the static analyzer purpose,
such as building the single-file library.
Reduced time spent in this test by reducing its scope :
just build the CLI, and obviously the library along it.
These are the only ones that really deserve to be analyzed.
Unfortunately, it still results in a number of false positives when using newer versions of scanbuild
(each version of scanbuild generates a different list of false positives).
These will have to be fixed before transfering to Github Actions.
Yann Collet [Sun, 29 Aug 2021 21:48:11 +0000 (14:48 -0700)]
accelerate versionsCompatibilityTest
by allowing parallel build of units,
and reducing optimization levels.
Parallel build is only effective on "recent" versions of `zstd`,
as previously, the list of units was passed as a list of source files,
which is something neither `make` nor `gcc` can parallelize.
So its impact is mildly effective (-20%).
Reducing optimization level to `-O1` makes compilation much faster.
It also makes runtime slower,
but in this test, compilation time dominates run time.
The savings are very significant (-50%).
On my test system, it reduces the length of this test from 13mn to 5mn.
Eli Schwartz [Mon, 9 Aug 2021 01:43:59 +0000 (21:43 -0400)]
meson: set the symbol visibility of the shared library to hidden
This matches the Makefile build. Due to one private xxhash symbol in use
by the program, it recompiles a private copy of xxhash.
Due to the test binaries making extensive (?) use of private symbols, it
doesn't even attempt to link to shared libzstd, and instead, all of the
original object files are added to libtestcommon itself for private
linkage. This, too, matches the Makefile build.
Eli Schwartz [Mon, 9 Aug 2021 01:11:20 +0000 (21:11 -0400)]
meson: fix warnings in build files
meson prefers that project-level options for Wall/Wextra/pedantic be
used, rather than hardcoding raw flags in add_project_arguments. If you
do the latter anyway, it raises a meson warning.
Set the default options for the project to use all this.
Also move the -Werror comment to the project default options with
appropriate format, but leave it commented out since it does not work.
Nick Terrell [Tue, 3 Aug 2021 04:02:31 +0000 (21:02 -0700)]
[fuzz] Add Huffman round trip fuzzer
* Add a Huffman round trip fuzzer
* Fix two minor bugs in Huffman that aren't exposed in zstd
- Incorrect weight comparison (weights are allowed to be equal to
table log).
- HUF_compress1X_usingCTable_internal() can return compressed
size >= source size, so the assert that `cSize <= 65535` isn't
correct, and it needs to be checked instead.
W. Felix Handte [Thu, 22 Jul 2021 16:37:35 +0000 (12:37 -0400)]
Fix DDSS Load
This PR fixes an incorrect comparison in figuring out `minChain` in
`ZSTD_dedicatedDictSearch_lazy_loadDictionary()`. This incorrect comparison
had been masked by the fact that `idx` was always 1, until @terrelln changed
that in #2726.
Nick Terrell [Thu, 15 Jul 2021 19:14:44 +0000 (12:14 -0700)]
[bug-fix] Fix a determinism bug with the DUBT
The DUBT can be non-deterministic if an index is equal to
`ZSTD_DUBT_UNSORTED_MARK`. Ensure that never happens by starting the
indices at 2.
This bug was found by the OSS-Fuzz determinism fuzzer. With this change
the fuzzer test passes. And I've confirmed that this is the root cause,
not just hiding the problem.
Aside: This took me a long time to figure out, because I thought I had
tried this first thing. But, apparantly I messed it up, because when I
was going through it again with @felixhandte, I was pointing out that it
wasn't the case, but it turns out it was.
projects / thirdparty / zstd.git / log
