Previously, the _BlocksOutputBuffer code creates a list of bytes objects to handle the output data from compression libraries. This ends up being slow due to the output buffer code needing to copy each bytes element of the list into the final bytes object buffer at the end of compression.
The new PyBytesWriter API introduced in PEP 782 is an ergonomic and fast method of writing data into a buffer that will later turn into a bytes object. Benchmarks show that using the PyBytesWriter API is 10-30% faster for decompression across a variety of settings. The performance gains are greatest when the decompressor is very performant, such as for Zstandard (and likely zlib-ng). Otherwise the decompressor can bottleneck decompression and the gains are more modest, but still sizable (e.g. 10% faster for zlib)!
Co-authored-by: Bénédikt Tran <10796600+picnixz@users.noreply.github.com>
In 121ed71f4e, mt_continue_should_break
was changed to be guarded by `Py_DEBUG`, but it's used in `compress_mt_continue_lock_held`
with just `assert`, so it needs to be available when `NDEBUG` is undefined
too.
`Py_DEBUG` implies `NDEBUG` is undefined, so we can check just that.
Fixes: 121ed71f4e
Move from using critical sections to locks for the (de)compression methods.
Since the methods allow other threads to run, we should use a lock rather
than a critical section.
* Add _zstd module for https://peps.python.org/pep-0784/
This commit introduces the `_zstd` module, with bindings to libzstd from
the pyzstd project. It also includes the unix build system configuration.
Windows build system support will be integrated independently as it
depends on integration with cpython-source-deps.
* Add _zstd to modules
* Fix path for compression.zstd module
* Ignore _zstd module like _io
* Expand module state macros to improve code quality
Also removes module state references from the classes in the _zstd
module and instead uses PyType_GetModuleState()
* Remove backticks suggested in review
Co-authored-by: Stan Ulbrych <89152624+StanFromIreland@users.noreply.github.com>
* Use critical sections to lock object state
This should avoid races and deadlocks.
* Remove compress/decompress and mark module as not reliant on the GIL
The `compress`/`decompress` functions will be moved to Python code for simplicity.
C implementations can always be re-added in the future.
Also, mark _zstd as not requiring the GIL.
* Lift critical section to avoid clang warning
* Respond to comments by picnixz
* Call out pyzstd explicitly in license description
Co-authored-by: Adam Turner <9087854+AA-Turner@users.noreply.github.com>
* Use a much more robust implementation...
... for `get_zstd_state_from_type`
Co-authored-by: Bénédikt Tran <10796600+picnixz@users.noreply.github.com>
* Use PyList_GetItemRef for thread safety purposes
* Use a macro for the minimum supported version
* remove const from primivite types
* Use PyMem_New in another spot
* Simplify error handling in _get_frame_size
* Another simplification of error handling in get_frame_info
* Rename _module_state to mod_state
* Rewrite comment explaining the context of the code
* Add link to pyzstd
* Add TODO about refactoring dict training code
* Use PyModule_AddObjectRef over PyModule_AddObject
PyModule_AddObject is soft-deprecated, so we should use PyModule_AddObjectRef
* Check result of OutputBufferGrow
* Simplify return logic in `add_constant_to_type`
Co-authored-by: Bénédikt Tran <10796600+picnixz@users.noreply.github.com>
* Ignore return value of _zstd_clear()
Co-authored-by: Bénédikt Tran <10796600+picnixz@users.noreply.github.com>
* Remove redundant comments
* Remove __reduce__ from ZstdDict
We should instead document that to pickle a dictionary a user should use
the `.dict_content` attribute.
* Use PyUnicode_FromFormat instead of a buffer
* Don't use C constants/types in error messages
* Make error messages easier to understand for Python users
* Lower minimum required version 1.4.0
* Use casts and make slot function signatures correct
* Be consistent with CPython on const usage
* Make else clauses in line with PEP 7
* Fix over-indented blocks in argument clinic
* Add critical section around ZSTD_DCtx_setParameter
* Add a TODO about refactoring critical sections
* Use Py_UNREACHABLE
* Move bytes operations out of Py_BEGIN_ALLOW_THREADS
* Add TODO about ensuring a lock is held
* Remove asserts that may not be correct
* Add TODO to make ZstdDict and others GC objects
* Make objects GC tracked
* Remove unused include
* Fix some memory issues
* Fix refleaks on module and in ZstdDict
* Update configure to check for ZDICT_finalizeDictionary
* Properly check version in configure
* exit(1) if check fails
* Use AC_RUN_IFELSE
* Use a define() to re-use version check
* Actually properly set _zstd module status based on version
---------
Co-authored-by: Stan Ulbrych <89152624+StanFromIreland@users.noreply.github.com>
Co-authored-by: Adam Turner <9087854+AA-Turner@users.noreply.github.com>
Co-authored-by: Bénédikt Tran <10796600+picnixz@users.noreply.github.com>
