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b9d6f64393
The zlib-ng library is a hard fork of the old and venerable zlib
library. It describes itself as zlib replacement with optimizations for
"next generation" systems. As such, it contains several implementations
of central algorithms using for example SSE2, AVX2 and other vectorized
CPU intrinsics that supposedly speed up in- and deflating data.
And indeed, compiling Git against zlib-ng leads to a significant speedup
when reading objects. The following benchmark uses git-cat-file(1) with
`--batch --batch-all-objects` in the Git repository:
Benchmark 1: zlib
Time (mean ± σ): 52.085 s ± 0.141 s [User: 51.500 s, System: 0.456 s]
Range (min … max): 52.004 s … 52.335 s 5 runs
Benchmark 2: zlib-ng
Time (mean ± σ): 40.324 s ± 0.134 s [User: 39.731 s, System: 0.490 s]
Range (min … max): 40.135 s … 40.484 s 5 runs
Summary
zlib-ng ran
1.29 ± 0.01 times faster than zlib
So we're looking at a ~25% speedup compared to zlib. This is of course
an extreme example, as it makes us read through all objects in the
repository. But regardless, it should be possible to see some sort of
speedup in most commands that end up accessing the object database.
The zlib-ng library provides a compatibility layer that makes it a
proper drop-in replacement for zlib: nothing needs to change in the
build system to support it. Unfortunately though, this mode isn't easy
to use on most systems because distributions do not allow you to install
zlib-ng in that way, as that would mean that the zlib library would be
globally replaced. Instead, many distributions provide a package that
installs zlib-ng without the compatibility layer. This version does
provide effectively the same APIs like zlib does, but all of the symbols
are prefixed with `zng_` to avoid symbol collisions.
Implement a new build option that allows us to link against zlib-ng
directly. If set, we redefine zlib symbols so that we use the `zng_`
prefixed versions thereof provided by that library. Like this, it
becomes possible to install both zlib and zlib-ng (without the compat
layer) and then pick whichever library one wants to link against for
Git.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
104 lines
6.2 KiB
Meson
104 lines
6.2 KiB
Meson
# Configuration for how Git behaves at runtime.
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option('default_pager', type: 'string', value: 'less',
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description: 'Fall-back pager.')
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option('default_editor', type: 'string', value: 'vi',
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description: 'Fall-back editor.')
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option('gitconfig', type: 'string', value: '/etc/gitconfig',
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description: 'Path to the global git configuration file.')
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option('gitattributes', type: 'string', value: '/etc/gitattributes',
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description: 'Path to the global git attributes file.')
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option('pager_environment', type: 'string', value: 'LESS=FRX LV=-c',
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description: 'Environment used when spawning the pager')
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option('perl_cpan_fallback', type: 'boolean', value: true,
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description: 'Install bundled copies of CPAN modules that serve as a fallback in case the modules are not available on the system.')
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option('runtime_prefix', type: 'boolean', value: false,
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description: 'Resolve ancillary tooling and support files relative to the location of the runtime binary instead of hard-coding them into the binary.')
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option('sane_tool_path', type: 'string', value: '',
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description: 'A colon-separated list of paths to prepend to PATH if your tools in /usr/bin are broken.')
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# Build information compiled into Git and other parts like documentation.
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option('build_date', type: 'string', value: '',
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description: 'Build date reported by our documentation.')
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option('built_from_commit', type: 'string', value: '',
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description: 'Commit that Git was built from reported by git-version(1).')
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option('user_agent', type: 'string', value: '',
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description: 'User agent reported to remote servers.')
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option('version', type: 'string', value: '',
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description: 'Version string reported by git-version(1) and other tools.')
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# Features supported by Git.
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option('curl', type: 'feature', value: 'enabled',
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description: 'Build helpers used to access remotes with the HTTP transport.')
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option('expat', type: 'feature', value: 'enabled',
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description: 'Build helpers used to push to remotes with the HTTP transport.')
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option('gettext', type: 'feature', value: 'auto',
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description: 'Build translation files.')
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option('gitweb', type: 'feature', value: 'auto',
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description: 'Build Git web interface. Requires Perl.')
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option('iconv', type: 'feature', value: 'auto',
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description: 'Support reencoding strings with different encodings.')
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option('pcre2', type: 'feature', value: 'enabled',
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description: 'Support Perl-compatible regular expressions in e.g. git-grep(1).')
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option('perl', type: 'feature', value: 'auto',
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description: 'Build tools written in Perl.')
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option('python', type: 'feature', value: 'auto',
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description: 'Build tools written in Python.')
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option('regex', type: 'feature', value: 'auto',
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description: 'Use the system-provided regex library instead of the bundled one.')
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# Backends.
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option('csprng_backend', type: 'combo', value: 'auto', choices: ['auto', 'arc4random', 'arc4random_bsd', 'getrandom', 'getentropy', 'rtlgenrandom', 'openssl', 'urandom'],
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description: 'The backend to use for generating cryptographically-secure pseudo-random numbers.')
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option('https_backend', type: 'combo', value: 'auto', choices: ['auto', 'openssl', 'CommonCrypto', 'none'],
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description: 'The HTTPS backend to use when connecting to remotes.')
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option('sha1_backend', type: 'combo', choices: ['openssl', 'block', 'sha1dc', 'CommonCrypto'], value: 'sha1dc',
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description: 'The backend used for hashing objects with the SHA1 object format.')
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option('sha1_unsafe_backend', type: 'combo', choices: ['openssl', 'block', 'CommonCrypto', 'none'], value: 'none',
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description: 'The backend used for hashing data with the SHA1 object format in case no cryptographic security is needed.')
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option('sha256_backend', type: 'combo', choices: ['openssl', 'nettle', 'gcrypt', 'block'], value: 'block',
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description: 'The backend used for hashing objects with the SHA256 object format.')
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option('zlib_backend', type: 'combo', choices: ['auto', 'zlib', 'zlib-ng'], value: 'auto',
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description: 'The backend used for compressing objects and other data.')
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# Build tweaks.
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option('macos_use_homebrew_gettext', type: 'boolean', value: true,
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description: 'Use gettext from Homebrew instead of the slightly-broken system-provided one.')
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# gitweb configuration.
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option('gitweb_config', type: 'string', value: 'gitweb_config.perl')
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option('gitweb_config_system', type: 'string', value: '/etc/gitweb.conf')
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option('gitweb_config_common', type: 'string', value: '/etc/gitweb-common.conf')
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option('gitweb_home_link_str', type: 'string', value: 'projects')
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option('gitweb_sitename', type: 'string', value: '')
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option('gitweb_projectroot', type: 'string', value: '/pub/git')
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option('gitweb_project_maxdepth', type: 'string', value: '2007')
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option('gitweb_export_ok', type: 'string', value: '')
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option('gitweb_strict_export', type: 'string', value: '')
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option('gitweb_base_url', type: 'string', value: '')
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option('gitweb_list', type: 'string', value: '')
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option('gitweb_hometext', type: 'string', value: 'indextext.html')
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option('gitweb_css', type: 'string', value: 'static/gitweb.css')
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option('gitweb_logo', type: 'string', value: 'static/git-logo.png')
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option('gitweb_favicon', type: 'string', value: 'static/git-favicon.png')
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option('gitweb_js', type: 'string', value: 'static/gitweb.js')
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option('gitweb_site_html_head_string', type: 'string', value: '')
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option('gitweb_site_header', type: 'string', value: '')
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option('gitweb_site_footer', type: 'string', value: '')
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option('highlight_bin', type: 'string', value: 'highlight')
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# Documentation.
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option('docs', type: 'array', choices: ['man', 'html'], value: [],
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description: 'Which documenattion formats to build and install.')
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option('default_help_format', type: 'combo', choices: ['man', 'html'], value: 'man',
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description: 'Default format used when executing git-help(1).')
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option('docs_backend', type: 'combo', choices: ['asciidoc', 'asciidoctor', 'auto'], value: 'auto',
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description: 'Which backend to use to generate documentation.')
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# Testing.
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option('tests', type: 'boolean', value: true,
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description: 'Enable building tests. This requires Perl, but is separate from the "perl" option such that you can build tests without Perl features enabled.')
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option('test_output_directory', type: 'string',
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description: 'Path to the directory used to store test outputs')
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option('fuzzers', type: 'boolean', value: false,
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description: 'Enable building fuzzers.')
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