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This macro protects x86_64-specific code, and a subsequent commit
will introduce AArch64-specific versions of that code. To prevent
confusion, let's rename it to clearly indicate that it's for
x86_64. We should likely move this code to its own file (perhaps
merging it with the AVX-512 popcount code), but that is left as a
future exercise.
Reviewed-by: "[email protected]" <[email protected]>
Reviewed-by: John Naylor <[email protected]>
Discussion: https://postgr.es/m/010101936e4aaa70-b474ab9e-b9ce-474d-a3ba-a3dc223d295c-000000%40us-west-2.amazonses.com
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Backpatch-through: 13
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Unlike TRY_POPCNT_FAST, which is defined in pg_bitutils.h, this
macro is defined in c.h (via pg_config.h), so we can check for it
earlier and avoid some unnecessary #includes on systems that lack
AVX-512 support.
Oversight in commit f78667bd91.
Discussion: https://postgr.es/m/Zy5K5Qmlb3Z4dsd4%40nathan
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The commonly supported way to specify multiple target options is to
surround the entire list with quotes and to use a comma (with no
extra spaces) as the delimiter.
Oversight in commit f78667bd91.
Discussion: https://postgr.es/m/Zy0jya8nF8CPpv3B%40nathan
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Presently, we check for compiler support for the required
intrinsics both with and without extra compiler flags (e.g.,
-mxsave), and then depending on the results of those checks, we
pick which files to compile with which flags. This is tedious and
complicated, and it results in unsustainable coding patterns such
as separate files for each portion of code may need to be built
with different compiler flags.
This commit introduces support for __attribute__((target(...))) and
uses it for the AVX-512 code. This simplifies both the
configure-time checks and the build scripts, and it allows us to
place the functions that use the intrinsics in files that we
otherwise do not want to build with special CPU instructions. We
are careful to avoid using __attribute__((target(...))) on
compilers that do not understand it, but we still perform the
configure-time checks in case the compiler allows using the
intrinsics without it (e.g., MSVC).
A similar change could likely be made for some of the CRC-32C code,
but that is left as a future exercise.
Suggested-by: Andres Freund
Reviewed-by: Raghuveer Devulapalli, Andres Freund
Discussion: https://postgr.es/m/20240731205254.vfpap7uxwmebqeaf%40awork3.anarazel.de
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Run pgindent, pgperltidy, and reformat-dat-files.
The pgindent part of this is pretty small, consisting mainly of
fixing up self-inflicted formatting damage from patches that
hadn't bothered to add their new typedefs to typedefs.list.
In order to keep it from making anything worse, I manually added
a dozen or so typedefs that appeared in the existing typedefs.list
but not in the buildfarm's list. Perhaps we should formalize that,
or better find a way to get those typedefs into the automatic list.
pgperltidy is as opinionated as always, and reformat-dat-files too.
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Commit 792752af4e added infrastructure for using AVX-512 intrinsic
functions, and this commit uses that infrastructure to optimize
visibilitymap_count(). Specificially, a new pg_popcount_masked()
function is introduced that applies a bitmask to every byte in the
buffer prior to calculating the population count, which is used to
filter out the all-visible or all-frozen bits as needed. Platforms
without AVX-512 support should also see a nice speedup due to the
reduced number of calls to a function pointer.
Co-authored-by: Ants Aasma
Discussion: https://postgr.es/m/BL1PR11MB5304097DF7EA81D04C33F3D1DCA6A%40BL1PR11MB5304.namprd11.prod.outlook.com
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Presently, pg_popcount() processes data in 32-bit or 64-bit chunks
when possible. Newer hardware that supports AVX-512 instructions
can use 512-bit chunks, which provides a nice speedup, especially
for larger buffers. This commit introduces the infrastructure
required to detect compiler and CPU support for the required
AVX-512 intrinsic functions, and it adds a new pg_popcount()
implementation that uses these functions. If CPU support for this
optimized implementation is detected at runtime, a function pointer
is updated so that it is used by subsequent calls to pg_popcount().
Most of the existing in-tree calls to pg_popcount() should benefit
from these instructions, and calls with smaller buffers should at
least not regress compared to v16. The new infrastructure
introduced by this commit can also be used to optimize
visibilitymap_count(), but that is left for a follow-up commit.
Co-authored-by: Paul Amonson, Ants Aasma
Reviewed-by: Matthias van de Meent, Tom Lane, Noah Misch, Akash Shankaran, Alvaro Herrera, Andres Freund, David Rowley
Discussion: https://postgr.es/m/BL1PR11MB5304097DF7EA81D04C33F3D1DCA6A%40BL1PR11MB5304.namprd11.prod.outlook.com
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