BLIS 0.9.0

This release contains a slew of improvements, new kernels and APIs, bugfixes, and more (including lots of code reduction). It also contains foundational support for an exciting new class of expert functionality: creating new operations without the need to duplicate the middleware that sits between the API and kernels.

Improvements present in 0.9.0:

Framework:

• Added various fields to obj_t that relate to storing function pointers to custom packm kernels, microkernels, etc as well as accessor functions to set and query those fields. (Devin Matthews)
• Enabled user-customized packm microkernels and variants via the aforementioned new obj_t fields. (Devin Matthews)
• Moved edge-case handling out of the macrokernel and into the gemm and gemmtrsm microkernels. This also required updating of APIs and definitions of all existing microkernels in kernels directory. Edge-case handling functionality is now facilitated via new preprocessor macros found in bli_edge_case_macro_defs.h. (Devin Matthews)
• Avoid gemmsup thread barriers when not packing A or B. This boosts performance for many small multithreaded problems. (Field Van Zee, AMD)
• Allow the 1m method to operate normally when single and double real-domain microkernels mix row and column I/O preference. (Field Van Zee, Devin Matthews, RuQing Xu)
• Removed support for execution of complex-domain level-3 operations via the 3m and 4m methods.
• Refactored herk, her2k, syrk, syr2k in terms of gemmt. (Devin Matthews)
• Defined setijv and getijv to set/get vector elements.
• Defined eqsc, eqv, and eqm operations to test equality between two scalars, vectors, or matrices.
• Added new bounds checking to setijm and getijm to prevent use of negative indices.
• Renamed membrk files/variables/functions to pba.
• Store error-checking level as a thread-local variable. (Devin Matthews)
• Add err_t* "return" parameter to bli_malloc_*() and friends.
• Switched internal mutexes of the sba and pba to static initialization.
• Changed return value method of bli_pack_get_pack_a(), bli_pack_get_pack_b().
• Fixed a bug that allows bli_init() to be called more than once (without segfaulting). (@lschork2, Minh Quan Ho, Devin Matthews)
• Removed a sanity check in bli_pool_finalize() that prevented BLIS from being re-initialized. (AMD)
• Fixed insufficient pool_t-growing logic in bli_pool.c, and always allocate at least one element in .block_ptrs array. (Minh Quan Ho)
• Cleanups related to the error message array in bli_error.c. (Minh Quan Ho)
• Moved language-related definitions from bli_macro_defs.h to a new header, bli_lang_defs.h.
• Renamed BLIS_SIMD_NUM_REGISTERS to BLIS_SIMD_MAX_NUM_REGISTERS and BLIS_SIMD_SIZE to BLIS_SIMD_MAX_SIZE for improved clarity. (Devin Matthews)
• Many minor bugfixes.
• Many cleanups, including removal of old and commented-out code.

Compatibility:

• Expanded BLAS layer to include support for ?axpby_() and ?gemm_batch_(). (Meghana Vankadari, AMD)
• Added gemm3m APIs to BLAS and CBLAS layers. (Bhaskar Nallani, AMD)
• Handle ?gemm_() invocations where m or n is unit by calling ?gemv_(). (Dipal M Zambare, AMD)
• Removed option to finalize BLIS after every BLAS call.
• Updated default definitions of bli_slamch() and bli_dlamch() to use constants from standard C library rather than values computed at runtime. (Devin Matthews)

Kernels:

• Added 512-bit SVE-based a64fx subconfiguration that uses empirically-tuned blocksizes (Stepan Nassyr, RuQing Xu)
• Added a vector-length agnostic armsve subconfig that computes blocksizes via an analytical model. (Stepan Nassyr)
• Added vector-length agnostic d/s/sh gemm kernels for Arm SVE. (Stepan Nassyr)
• Added gemmsup kernels to the armv8a kernel set for use in new Apple Firestorm subconfiguration. (RuQing Xu)
• Added 512-bit SVE dpackm kernels (16xk and 10xk) with in-register transpose. (RuQing Xu)
• Extended 256-bit SVE dpackm kernels by Linaro Ltd. to 512-bit for size 12xk. (RuQing Xu)
• Reorganized register usage in bli_gemm_armv8a_asm_d6x8.c to accommodate clang. (RuQing Xu)
• Added saxpyf/daxpyf/caxpyf kernels to zen kernel set. (Dipal M Zambare, AMD)
• Added vzeroupper instruction to haswell microkernels. (Devin Matthews)
• Added explicit beta == 0 handling in s/d armsve and armv7a gemm microkernels. (Devin Matthews)
• Added a unique tag to branch labels to accommodate clang. (Devin Matthews, Jeff Hammond)
• Fixed a copy-paste bug in the loading of kappa_i in the two assembly cpackm kernels in haswell kernel set. (Devin Matthews)
• Fixed a bug in Mx1 gemmsup haswell kernels whereby the vhaddpd instruction is used with uninitialized registers. (Devin Matthews)
• Fixed a bug in the power10 microkernel I/O. (Nicholai Tukanov)
• Many other Arm kernel updates and fixes. (RuQing Xu)

Extras:

• Added support for addons, which are similar to sandboxes but do not require the user to implement any particular operation.
• Added a new gemmlike sandbox to allow rapid prototyping of gemm-like operations.
• Various updates and improvements to the power10 sandbox, including a new testsuite. (Nicholai Tukanov)

Build system:

• Added explicit support for AMD's Zen3 microarchitecture. (Dipal M Zambare, AMD, Field Van Zee)
• Added runtime microarchitecture detection for Arm. (Dave Love, RuQing Xu, Devin Matthews)
• Added a new configure option --[en|dis]able-amd-frame-tweaks that allows BLIS to compile certain framework files (each with the _amd suffix) that have been customized by AMD for improved performance (provided that the targeted configuration is eligible). By default, the more portable counterparts to these files are compiled. (Field Van Zee, AMD)
• Added an explicit compiler predicate (is_win) for Windows in configure. (Devin Matthews)
• Use -march=haswell instead of -march=skylake-avx512 on Windows. (Devin Matthews, @h-vetinari)
• Fixed configure breakage on MacOSX by accepting either clang or LLVM in vendor string. (Devin Matthews)
• Blacklist clang10/gcc9 and older for armsve subconfig.
• Added a configure option to control whether or not to use @rpath. (Devin Matthews)
• Added armclang detection to configure. (Devin Matthews)
• Use @path-based install name on MacOSX and use relocatable RPATH entries for testsuite binaries. (Devin Matthews)
• For environment variables CC, CXX, FC, PYTHON, AR, and RANLIB, configure will now print an error message and abort if a user specifies a specific tool and that tool is not found. (Field Van Zee, Devin Matthews)
• Added symlink to blis.pc.in for out-of-tree builds. (Andrew Wildman)
• Register optimized real-domain copyv, setv, and swapv kernels in zen subconfig. (Dipal M Zambare, AMD)
• Added Apple Firestorm (A14/M1) subconfiguration, firestorm. (RuQing Xu)
• Added armsve subconfig to arm64 configuration family. (RuQing Xu)
• Allow using clang with the thunderx2 subconfiguration. (Devin Matthews)
• Fixed a subtle substitution bug in configure. (Chengguo Sun)
• Updated top-level Makefile to reflect a dependency on the "flat" blis.h file for the BLIS and BLAS testsuite objects. (Devin Matthews)
• Mark xerbla_() as a "weak" symbol on MacOSX. (Devin Matthews)
• Fixed a long-standing bug in common.mk whereby the header path to cblas.h was omitted from the compiler flags when compiling CBLAS files within BLIS.
• Added a custom-made recursive sed script to build directory.
• Minor cleanups and fixes to configure, common.mk, and others.

Testing:

• Fixed a race condition in the testsuite when the SALT option (simulate application-level threading) is enabled. (Devin Matthews)
• Test 1m method execution during make check. (Devin Matthews)
• Test make install in Travis CI. (Devin Matthews)
• Test C++ in Travis CI to make sure blis.h is C++-compatible. (Devin Matthews)
• Disabled SDE testing of pre-Zen microarchitectures via Travis CI.
• Added Travis CI support for testing Arm SVE. (RuQing Xu)
• Updated SDE usage so that it is downloaded from a separate repository (ci-utils) in our GitHub organization. (Field Van Zee, Devin Matthews)
• Updated octave scripts in test/3 to be robust against missing datasets as well as to fixed a few minor issues.
• Added test_axpbyv.c and test_gemm_batch.c test driver files to test directory. (Meghana Vankadari, AMD)
• Support all four datatypes in her, her2, herk, and her2k drivers in test directory. (Madan mohan Manokar, AMD)

Documentation:

• Added documentation for: setijv, getijv, eqsc, eqv, eqm.
• Added docs/Addons.md.
• Added dedicated "Performance" and "Example Code" sections to README.md.
• Updated README.md.
• Updated docs/Sandboxes.md.
• Updated docs/Multithreading.md. (Devin Matthews)
• Updated docs/KernelHowTo.md.
• Updated docs/Performance.md to report Fujitsu A64fx (512-bit SVE) results. (RuQing Xu)
• Updated docs/Performance.md to report Graviton2 Neoverse N1 results. (Nicholai Tukanov)
• Updated docs/FAQ.md with new questions.
• Fixed typos in docs/FAQ.md. (Gaëtan Cassiers)
• Various other minor fixes.