Details:
- Implemented a sophisticated data structure and set of APIs that track
the small blocks of memory (around 80-100 bytes each) used when
creating nodes for control and thread trees (cntl_t and thrinfo_t) as
well as thread communicators (thrcomm_t). The purpose of the small
block allocator, or sba, is to allow the library to transition into a
runtime state in which it does not perform any calls to malloc() or
free() during normal execution of level-3 operations, regardless of
the threading environment (potentially multiple application threads
as well as multiple BLIS threads). The functionality relies on a new
data structure, apool_t, which is (roughly speaking) a pool of
arrays, where each array element is a pool of small blocks. The outer
pool, which is protected by a mutex, provides separate arrays for each
application thread while the arrays each handle multiple BLIS threads
for any given application thread. The design minimizes the potential
for lock contention, as only concurrent application threads would
need to fight for the apool_t lock, and only if they happen to begin
their level-3 operations at precisely the same time. Thanks to Kiran
Varaganti and AMD for requesting this feature.
- Added a configure option to disable the sba pools, which are enabled
by default; renamed the --[dis|en]able-packbuf-pools option to
--[dis|en]able-pba-pools; and rewrote the --help text associated with
this new option and consolidated it with the --help text for the
option associated with the sba (--[dis|en]able-sba-pools).
- Moved the membrk field from the cntx_t to the rntm_t. We now pass in
a rntm_t* to the bli_membrk_acquire() and _release() APIs, just as we
do for bli_sba_acquire() and _release().
- Replaced all calls to bli_malloc_intl() and bli_free_intl() that are
used for small blocks with calls to bli_sba_acquire(), which takes a
rntm (in addition to the bytes requested), and bli_sba_release().
These latter two functions reduce to the former two when the sba pools
are disabled at configure-time.
- Added rntm_t* arguments to various cntl_t and thrinfo_t functions, as
required by the new usage of bli_sba_acquire() and _release().
- Moved the freeing of "old" blocks (those allocated prior to a change
in the block_size) from bli_membrk_acquire_m() to the implementation
of the pool_t checkout function.
- Miscellaneous improvements to the pool_t API.
- Added a block_size field to the pblk_t.
- Harmonized the way that the trsm_ukr testsuite module performs packing
relative to that of gemmtrsm_ukr, in part to avoid the need to create
a packm control tree node, which now requires a rntm_t that has been
initialized with an sba and membrk.
- Re-enable explicit call bli_finalize() in testsuite so that users who
run the testsuite with memory tracing enabled can check for memory
leaks.
- Manually imported the compact/minor changes from 61441b24 that cause
the rntm to be copied locally when it is passed in via one of the
expert APIs.
- Reordered parameters to various bli_thrcomm_*() functions so that the
thrcomm_t* to the comm being modified is last, not first.
- Added more descriptive tracing for allocating/freeing small blocks and
formalized via a new configure option: --[dis|en]able-mem-tracing.
- Moved some unused scalm code and headers into frame/1m/other.
- Whitespace changes to bli_pthread.c.
- Regenerated build/libblis-symbols.def.
Details:
- Updated the API and semantics of packm kernels such that they must now
handle edge cases, meaning that a c-by-k packm kernel must be able to
pack edge cases that are fewer than c rows/columns and be able to
zero-fill the remaining elements. They must also be able to zero-fill
the equivalent region when copying fewer than k columns/rows (which is
needed by trsm). The new packm kernel API is generally:
void packm_kernel
(
conj_t conja,
dim_t cdim,
dim_t n,
dim_t n_max,
ctype* restrict kappa,
ctype* restrict a, inc_t inca, inc_t lda,
ctype* restrict p, inc_t ldp,
cntx_t* restrict cntx
);
where cdim and n are the dimensions (short and long, respectively) of
the submatrix being copied from the source matrix A, and n_max is the
"full" long dimension (corresponding to the k dimension in gemm) of
the micropanel. The "full" short dimension (corresponding to the
register blocksize MR or NR) is not part of the API because it is
known intrinsically by the packm kernel implementation. Thanks to
Devin Matthews for prompting us to make this change (#282).
- Updated all reference packm kernels in ref_kernels/1m according to
above changes, as well as all optimized packm kernels (which only
consisted of those for knl).
- Bumped the major soname version number in 'so_version' to 2. At first
I was considering leaving it unchanged, but I couldn't escape the
reality that the packm kernel API is much closer to an expert API
than it is some obscure helper function interface within the framework
that nobody would ever notice.
- Removed reference packm kernels for mr/nr = 30. The only sub-config
that would have been using those kernels is knc, which is likely no
longer being used by very many people (if any). (This also mostly
offset the larger object code footprint incurred by moving the edge-
case handling into the individual packm kernels.)
- Fixed an obscure race condition for 3mh and 4mh induced methods in
which those implementations were modifying the contexts stored in the
gks rather than a local copy.
- Fixed a minor bug in the testsuite that prevented non-1m-based induced
method implementations of trsm from executing.
Details:
- Removed explicit reference to The University of Texas at Austin in the
third clause of the license comment blocks of all relevant files and
replaced it with a more all-encompassing "copyright holder(s)".
- Removed duplicate words ("derived") from a few kernels' license
comment blocks.
- Homogenized license comment block in kernels/zen/3/bli_gemm_small.c
with format of all other comment blocks.
Details:
- Removed four trailing spaces after "BLIS" that occurs in most files'
commented-out license headers.
- Added UT copyright lines to some files. (These files previously had
only AMD copyright lines but were contributed to by both UT and AMD.)
- In some files' copyright lines, expanded 'The University of Texas' to
'The University of Texas at Austin'.
- Fixed various typos/misspellings in some license headers.
Details:
- Added links, and sandbox language to README.md.
- Adjusted some comments in high-level level-3 object functions to make
clear what bli_thread_init_rntm() does.
Details:
- Defined a new struct datatype, rntm_t (runtime), to house the thrloop
field of the cntx_t (context). The thrloop array holds the number of
ways of parallelism (thread "splits") to extract per level-3
algorithmic loop until those values can be used to create a
corresponding node in the thread control tree (thrinfo_t structure),
which (for any given level-3 invocation) usually happens by the time
the macrokernel is called for the first time.
- Relocating the thrloop from the cntx_t remedies a thread-safety issue
when invoking level-3 operations from two or more application threads.
The race condition existed because the cntx_t, a pointer to which is
usually queried from the global kernel structure (gks), is supposed to
be a read-only. However, the previous code would write to the cntx_t's
thrloop field *after* it had been queried, thus violating its read-only
status. In practice, this would not cause a problem when a sequential
application made a multithreaded call to BLIS, nor when two or more
application threads used the same parallelization scheme when calling
BLIS, because in either case all application theads would be using
the same ways of parallelism for each loop. The true effects of the
race condition were limited to situations where two or more application
theads used *different* parallelization schemes for any given level-3
call.
- In remedying the above race condition, the application or calling
library can now specify the parallelization scheme on a per-call basis.
All that is required is that the thread encode its request for
parallelism into the rntm_t struct prior to passing the address of the
rntm_t to one of the expert interfaces of either the typed or object
APIs. This allows, for example, one application thread to extract 4-way
parallelism from a call to gemm while another application thread
requests 2-way parallelism. Or, two threads could each request 4-way
parallelism, but from different loops.
- A rntm_t* parameter has been added to the function signatures of most
of the level-3 implementation stack (with the most notable exception
being packm) as well as all level-1v, -1d, -1f, -1m, and -2 expert
APIs. (A few internal functions gained the rntm_t* parameter even
though they currently have no use for it, such as bli_l3_packm().)
This required some internal calls to some of those functions to
be updated since BLIS was already using those operations internally
via the expert interfaces. For situations where a rntm_t object is
not available, such as within packm/unpackm implementations, NULL is
passed in to the relevant expert interfaces. This is acceptable for
now since parallelism is not obtained for non-level-3 operations.
- Revamped how global parallelism is encoded. First, the conventional
environment variables such as BLIS_NUM_THREADS and BLIS_*_NT are only
read once, at library initialization. (Thanks to Nathaniel Smith for
suggesting this to avoid repeated calls getenv(), which can be slow.)
Those values are recorded to a global rntm_t object. Public APIs, in
bli_thread.c, are still available to get/set these values from the
global rntm_t, though now the "set" functions have additional logic
to ensure that the values are set in a synchronous manner via a mutex.
If/when NULL is passed into an expert API (meaning the user opted to
not provide a custom rntm_t), the values from the global rntm_t are
copied to a local rntm_t, which is then passed down the function stack.
Calling a basic API is equivalent to calling the expert APIs with NULL
for the cntx and rntm parameters, which means the semantic behavior of
these basic APIs (vis-a-vis multithreading) is unchanged from before.
- Renamed bli_cntx_set_thrloop_from_env() to bli_rntm_set_ways_for_op()
and reimplemented, with the function now being able to treat the
incoming rntm_t in a manner agnostic to its origin--whether it came
from the application or is an internal copy of the global rntm_t.
- Removed various global runtime APIs for setting the number of ways of
parallelism for individual loops (e.g. bli_thread_set_*_nt()) as well
as the corresponding "get" functions. The new model simplifies these
interfaces so that one must either set the total number of threads, OR
set all of the ways of parallelism for each loop simultaneously (in a
single function call).
- Updated sandbox/ref99 according to above changes.
- Rewrote/augmented docs/Multithreading.md to document the three methods
(and two specific ways within each method) of requesting parallelism
in BLIS.
- Removed old, disabled code from bli_l3_thrinfo.c.
- Whitespace changes to code (e.g. bli_obj.c) and docs/BuildSystem.md.
Details:
- Converted most C preprocessor macros in bli_param_macro_defs.h and
bli_obj_macro_defs.h to static functions.
- Reshuffled some functions/macros to bli_misc_macro_defs.h and also
between bli_param_macro_defs.h and bli_obj_macro_defs.h.
- Changed obj_t-initializing macros in bli_type_defs.h to static
functions.
- Removed some old references to BLIS_TWO and BLIS_MINUS_TWO from
bli_constants.h.
- Whitespace changes in select files (four spaces to single tab).
Details:
- Fixed a bug in the way the bli_gemm1m_cntx_ref() function (defined in
ref_kernels/bli_cntx_ref.c) initializes its context for 1m execution.
Previously, the function probed the context that was in the process of
being updated for use with 1m--this context being previously
initialized/copied from a native context--for its storage preference
to determine which "variant" (row- or column-oriented) of 1m would be
needed. However, the _cntx_ref() function was not updating the method
field of the context until AFTER this query, and the conditional which
depended on it, had taken place, meaning the storage preference query
function would mistakenly think the context was for native execution,
since the context's method field would still be set to BLIS_NAT. This
would lead it to incorrectly grab the storage preference of the complex
domain microkernel rather than the corresponding real domain
microkernel, which could cause the storage preference predicate to
evaluate to the wrong value, which would lead to the _cntx_ref()
function choosing the wrong variant. This could lead to undefined
behavior at runtime. The method is now explicitly set within the
context prior to calling the storage preference query function.
- Updated comments in frame/ind/oapi/bli_l3_3m4m1m_oapi.c.
- Fixed a typo in the commented-out CFLAGS in config/zen/make_defs.mk,
which are appropriate for gcc 6.x and newer. (Mistakenly used
-march=bdver4 instead of -march=znver1.)
Details:
- Defined two new functions in bli_init.c: bli_init_once() and
bli_finalize_once(). Each is implemented with pthread_once(), which
guarantees that, among the threads that pass in the same pthread_once_t
data structure, exactly one thread will execute a user-defined function.
(Thus, there is now a runtime dependency against libpthread even when
multithreading is not enabled at configure-time.)
- Added calls to bli_init_once() to top-level user APIs for all
computational operations as well as many other functions in BLIS to
all but guarantee that BLIS will self-initialize through the normal
use of its functions.
- Rewrote and simplified bli_init() and bli_finalize() and related
functions.
- Added -lpthread to LDFLAGS in common.mk.
- Modified the bli_init_auto()/_finalize_auto() functions used by the
BLAS compatibility layer to take and return no arguments. (The
previous API that tracked whether BLIS was initialized, and then
only finalized if it was initialized in the same function, was too
cute by half and borderline useless because by default BLIS stays
initialized when auto-initialized via the compatibility layer.)
- Removed static variables that track initialization of the sub-APIs in
bli_const.c, bli_error.c, bli_init.c, bli_memsys.c, bli_thread, and
bli_ind.c. We don't need to track initialization at the sub-API level,
especially now that BLIS can self-initialize.
- Added a critical section around the changing of the error checking
level in bli_error.c.
- Deprecated bli_ind_oper_has_avail() as well as all functions
bli_<opname>_ind_get_avail(), where <opname> is a level-3 operation
name. These functions had no use cases within BLIS and likely none
outside of BLIS.
- Commented out calls to bli_init() and bli_finalize() in testsuite's
main() function, and likewise for standalone test drivers in 'test'
directory, so that self-initialization is exercised by default.
Details:
- Reworked the build system around a configuration registry file, named
config_registry', that identifies valid configuration targets, their
constituent sub-configurations, and the kernel sets that are needed by
those sub-configurations. The build system now facilitates the building
of a single library that can contains kernels and cache/register
blocksizes for multiple configurations (microarchitectures). Reference
kernels are also built on a per-configuration basis.
- Updated the Makefile to use new variables set by configure via the
config.mk.in template, such as CONFIG_LIST, KERNEL_LIST, and KCONFIG_MAP,
in determining which sub-configurations (CONFIG_LIST) and kernel sets
(KERNEL_LIST) are included in the library, and which make_defs.mk files'
CFLAGS (KCONFIG_MAP) are used when compiling kernels.
- Reorganized 'kernels' directory into a "flat" structure. Renamed kernel
functions into a standard format that includes the kernel set name
(e.g. 'haswell'). Created a "bli_kernels_<kernelset>.h" file in each
kernels sub-directory. These files exist to provide prototypes for the
kernels present in those directories.
- Reorganized reference kernels into a top-level 'ref_kernels' directory.
This directory includes a new source file, bli_cntx_ref.c (compiled on
a per-configuration basis), that defines the code needed to initialize
a reference context and a context for induced methods for the
microarchitecture in question.
- Rewrote make_defs.mk files in each configuration so that the compiler
variables (e.g. CFLAGS) are "stored" (renamed) on a per-configuration
basis.
- Modified bli_config.h.in template so that bli_config.h is generated with
#defines for the config (family) name, the sub-configurations that are
associated with the family, and the kernel sets needed by those
sub-configurations.
- Deprecated all kernel-related information in bli_kernel.h and transferred
what remains to new header files named "bli_arch_<configname>.h", which
are conditionally #included from a new header bli_arch.h. These files
are still needed to set library-wide parameters such as custom
malloc()/free() functions or SIMD alignment values.
- Added bli_cntx_init_<configname>.c files to each configuration directory.
The files contain a function, named the same as the file, that initializes
a "native" context for a particular configuration (microarchitecture). The
idea is that optimized kernels, if available, will be initialized into
these contexts. Other fields will retain pointers to reference functions,
which will be compiled on a per-configuration basis. These bli_cntx_init_*()
functions will be called during the initialization of the global kernel
structure. They are thought of as initializing for "native" execution, but
they also form the basis for contexts that use induced methods. These
functions are prototyped, along with their _ref() and _ind() brethren, by
prototype-generating macros in bli_arch.h.
- Added a new typedef enum in bli_type_defs.h to define an arch_t, which
identifies the various sub-configurations.
- Redesigned the global kernel structure (gks) around a 2D array of cntx_t
structures (pointers to cntx_t, actually). The first dimension is indexed
over arch_t and the inner dimension is the ind_t (induced method) for
each microarchitecture. When a microarchitecture (configuration) is
"registered" at init-time, the inner array for that configuration in the
2D array is initialized (and allocated, if it hasn't been already). The
cntx_t slot for BLIS_NAT is initialized immediately and those for other
induced method types are initialized and cached on-demand, as needed. At
cntx_t registration, we also store function pointers to cntx_init functions
that will initialize (a) "reference" contexts and (b) contexts for use with
induced methods. We don't cache the full contexts for reference contexts
since they are rarely needed. The functions that initialize these two kinds
of contexts are generated automatically for each targeted sub-configuration
from cpp-templatized code at compile-time. Induced method contexts that
need "stage" adjustments can still obtain them via functions in
bli_cntx_ind_stage.c.
- Added new functions and functionality to bli_cntx.c, such as for setting
the level-1f, level-1v, and packm kernels, and for converting a native
context into one for executing an induced method.
- Moved the checking of register/cache blocksize consistency from being cpp
macros in bli_kernel_macro_defs.h to being runtime checks defined in
bli_check.c and called from bli_gks_register_cntx() at the time that the
global kernel structure's internal context is initialized for a given
microarchitecture/configuration.
- Deprecated all of the old per-operation bli_*_cntx.c files and removed
the previous operation-level cntx_t_init()/_finalize() invocations.
Instead, we now query the gks for a suitable context, usually via
bli_gks_query_cntx().
- Deprecated support for the 3m2 and 3m3 induced methods. (They required
hackery that I was no longer willing to support.)
- Consolidated the 1e and 1r packm kernels for any given register blocksize
into a single kernel that will branch on the schema and support packing
to both formats.
- Added the cntx_t* argument to all packm kernel signatures.
- Deprecated the local function pointer array in all bli_packm_cxk*.c files
and instead obtain the packm kernel from the cntx_t.
- Added bli_calloc_intl(), which serves as the calloc-equivalent to to
bli_malloc_intl(). Useful when we wish to allocate and initialize to
zero/NULL.
- Converted existing cpp macro functions defined in bli_blksz.h, bli_func.h,
bli_cntx.h into static functions.
Details:
- Commented out code in frame/ind/oapi/bli_l3_3m4m1m_oapi.c that was
specifically inserted to facilitate the benchmarking of 1m block-panel
and panel-block algorithms.
- Updates to test/3m4m/Makefile, runme.sh script, and test_gemm.c to
reflect changes used/needed during benchmarking.
Details:
- Defined bli_gemmbp_cntl_create(), bli_gemmpb_cntl_create(), with the
body of bli_gemm_cntl_create() replaced with a call to the former.
- Defined bli_cntl_free_w_thrinfo(), bli_cntl_free_wo_thrinfo(). Now,
bli_cntl_free() can check if the thread parameter is NULL, and if so,
call the latter, and otherwise call the former.
- Defined bli_gemm1mbp_cntx_init(), bli_gemm1mpb_cntx_init(), both in
terms of bli_gemm1mxx_cntx_init(), which behaves the same as
bli_gemm1m_cntx_init() did before, except that an extra bool parameter
(is_pb) is used to support both bp and pb algorithms (including to
support the anti-preference field described below).
- Added support for "anti-preference" in context. The anti_pref field,
when true, will toggle the boolean return value of routines such as
bli_cntx_l3_ukr_eff_prefers_storage_of(), which has the net effect of
causing BLIS to transpose the operation to achieve disagreement (rather
than agreement) between the storage of C and the micro-kernel output
preference. This disagreement is needed for panel-block implementations,
since they induce a transposition of the suboperation immediately before
the macro-kernel is called, which changes the apparent storage of C. For
now, anti-preference is used only with the pb algorithm for 1m (and not
with any other non-1m implementation).
- Defined new functions,
bli_cntx_l3_ukr_eff_prefers_storage_of()
bli_cntx_l3_ukr_eff_dislikes_storage_of()
bli_cntx_l3_nat_ukr_eff_prefers_storage_of()
bli_cntx_l3_nat_ukr_eff_dislikes_storage_of()
which are identical to their non-"eff" (effectively) counterparts except
that they take the anti-preference field of the context into account.
- Explicitly initialize the anti-pref field to FALSE in
bli_gks_cntx_set_l3_nat_ukr_prefs().
- Added bli_gemm_ker_var1.c, which implements a panel-block macro-kernel
in terms of the existing block-panel macro-kernel _ker_var2(). This
technique requires inducing transposes on all operands and swapping
the A and B.
- Changed bli_obj_induce_trans() macro so that pack-related fields are
also changed to reflect the induced transposition.
- Added a temporary hack to bli_l3_3m4m1m_oapi.c that allows us to easily
specify the 1m algorithm (block-panel or panel-block).
- Renamed the following cntx_t-related macros:
bli_cntx_get_pack_schema_a() -> bli_cntx_get_pack_schema_a_block()
bli_cntx_get_pack_schema_b() -> bli_cntx_get_pack_schema_b_panel()
bli_cntx_get_pack_schema_c() -> bli_cntx_get_pack_schema_c_panel()
and updated all instantiations. Also updated the field names in the
cntx_t struct.
- Comment updates.
Details:
- Implemented the 1m method for inducing complex domain matrix
multiplication. 1m support has been added to all level-3 operations,
including trsm, and is now the default induced method when native
complex domain gemm microkernels are omitted from the configuration.
- Updated _cntx_init() operations to take a datatype parameter. This was
needed for the corresponding function for 1m (because 1m requires us
to choose between column-oriented or row-oriented execution, which
requires us to query the context for the storage preference of the
gemm microkernel, which requires knowing the datatype) but I decided
that it made sense for consistency to add the parameter to all other
cntx initialization functions as well, even though those functions
don't use the parameter.
- Updated bli_cntx_set_blkszs() and bli_gks_cntx_set_blkszs() to take
a second scalar for each blocksize entry. The semantic meaning of the
two scalars now is that the first will scale the default blocksize
while the second will scale the maximum blocksize. This allows scaling
the two independently, and was needed to support 1m, which requires
scaling for a register blocksize but not the register storage
blocksize (ie: "packdim") analogue.
- Deprecated bli_blksz_reduce_dt_to() and defined two new functions,
bli_blksz_reduce_def_to() and bli_blksz_reduce_max_to(), for reducing
default and maximum blocksizes to some desired blocksize multiple.
These functions are needed in the updated definitions of
bli_cntx_set_blkszs() and bli_gks_cntx_set_blkszs().
- Added support for the 1e and 1r packing schemas to packm, including
1e/1r packing kernels.
- Added a minor optimization to bli_gemm_ker_var2() that allows, under
certain circumstances (specifically, real domain beta and row- or
column-stored matrix C), the real domain macrokernel and microkernel
to be called directly, rather than using the virtual microkernel
via the complex domain macrokernel, which carries a slight additional
amount of overhead.
- Added 1m support to the testsuite.
- Added 1m support to Makefile and runme.sh in test/3m4m. Also simplified
some code in test_gemm.c driver.
