Details:
- Added multithreading support to the sup framework (via either OpenMP
or pthreads). Both variants 1n and 2m now have the appropriate
threading infrastructure, including data partitioning logic, to
parallelize computation. This support handles all four combinations
of packing on matrices A and B (neither, A only, B only, or both).
This implementation tries to be a little smarter when automatic
threading is requested (e.g. via BLIS_NUM_THREADS) in that it will
recalculate the factorization in units of micropanels (rather than
using the raw dimensions) in bli_l3_sup_int.c, when the final
problem shape is known and after threads have already been spawned.
- Implemented bli_?packm_sup_var2(), which packs to conventional row-
or column-stored matrices. (This is used for the rrc and crc storage
cases.) Previously, copym was used, but that would no longer suffice
because it could not be parallelized.
- Minor reorganization of packing-related sup functions. Specifically,
bli_packm_sup_init_mem_[ab]() are called from within packm_sup_[ab]()
instead of from the variant functions. This has the effect of making
the variant functions more readable.
- Added additional bli_thrinfo_set_*() static functions to bli_thrinfo.h
and inserted usage of these functions within bli_thrinfo_init(), which
previously was accessing thrinfo_t fields via the -> operator.
- Renamed bli_partition_2x2() to bli_thread_partition_2x2().
- Added an auto_factor field to the rntm_t struct in order to track
whether automatic thread factorization was originally requested.
- Added new test drivers in test/supmt that perform multithreaded sup
tests, as well as appropriate octave/matlab scripts to plot the
resulting output files.
- Added additional language to docs/Multithreading.md to make it clear
that specifying any BLIS_*_NT variable, even if it is set to 1, will
be considered manual specification for the purposes of determining
whether to auto-factorize via BLIS_NUM_THREADS.
- Minor comment updates.
Details:
- Implemented optional packing for A or B (or both) within the sup
framework (which currently only supports gemm). The request for
packing either matrix A or matrix B can be made via setting
environment variables BLIS_PACK_A or BLIS_PACK_B (to any
non-zero value; if set, zero means "disable packing"). It can also
be made globally at runtime via bli_pack_set_pack_a() and
bli_pack_set_pack_b() or with individual rntm_t objects via
bli_rntm_set_pack_a() and bli_rntm_set_pack_b() if using the expert
interface of either the BLIS typed or object APIs. (If using the
BLAS API, environment variables are the only way to communicate the
packing request.)
- One caveat (for now) with the current implementation of selective
packing is that any blocksize extension registered in the _cntx_init
function (such as is currently used by haswell and zen subconfigs)
will be ignored if the affected matrix is packed. The reason is
simply that I didn't get around to implementing the necessary logic
to pack a larger edge-case micropanel, though this is entirely
possible and should be done in the future.
- Spun off the variant-choosing portion of bli_gemmsup_ref() into
bli_gemmsup_int(), in bli_l3_sup_int.c.
- Added new files, bli_l3_sup_packm_a.c, bli_l3_sup_packm_b.c, along
with corresponding headers, in which higher-level packm-related
functions are defined for use within the sup framework. The actual
packm variant code resides in bli_l3_sup_packm_var.c.
- Pass the following new parameters into var1n and var2m: packa, packb
bool_t's, pointer to a rntm_t, pointer to a cntl_t (which is for now
always NULL), and pointer to a thrinfo_t* (which for nowis the address
of the global single-threaded packm thread control node).
- Added panel strides ps_a and ps_b to the auxinfo_t structure so that
the millikernel can query the panel stride of the packed matrix and
step through it accordingly. If the matrix isn't packed, the panel
stride of interest for the given millikernel will be set to the
appropriate value so that the mkernel may step through the unpacked
matrix as it normally would.
- Modified the rv_6x8m and rv_6x8n millikernels to read the appropriate
panel strides (ps_a and ps_b, respectively) instead of computing them
on the fly.
- Spun off the environment variable getting and setting functions into
a new file, bli_env.c (with a corresponding prototype header). These
functions are now used by the threading infrastructure (e.g.
BLIS_NUM_THREADS, BLIS_JC_NT, etc.) as well as the selective packing
infrastructure (e.g. BLIS_PACK_A, BLIS_PACK_B).
- Added a static initializer for mem_t objects, BLIS_MEM_INITIALIZER.
- Added a static initializer for pblk_t objects, BLIS_PBLK_INITIALIZER,
for use within the definition of BLIS_MEM_INITIALIZER.
- Moved the global_rntm object to bli_rntm.c and extern it where needed.
This means that the function bli_thread_init_rntm() was renamed to
bli_rntm_init_from_global() and relocated accordingly.
- Added a new bli_pack.c function, which serves as the home for
functions that manage the pack_a and pack_b fields of the global
rntm_t, including from environment variables, just as we have
functions to manage the threading fields of the global rntm_t in
bli_thread.c.
- Reorganized naming for files in frame/thread, which mostly involved
spinning off the bli_l3_thread_decorator() functions into their own
files. This change makes more sense when considering the further
addition of bli_l3_sup_thread_decorator() functions (for now limited
only to the single-threaded form found in the _single.c file).
- Explicitly initialize the reference sup handlers in both
bli_cntx_init_haswell.c and bli_cntx_init_zen.c so that it's more
obvious how to customize to a different handler, if desired.
- Removed various snippets of disabled code.
- Various comment updates.
