Details:
- Adjusted the method by which micropanels are assigned to threads in
the 2nd (jr) and 1st (ir) loops around the microkernel to (mostly)
employ contiguous "slab" partitioning rather than interleaved (round
robin) partitioning. The new partitioning schemes and related details
for specific families of operations are listed below:
- gemm: slab partitioning.
- herk: slab partitioning for region corresponding to non-triangular
region of C; round robin partitioning for triangular region.
- trmm: slab partitioning for region corresponding to non-triangular
region of B; round robin partitioning for triangular region.
(NOTE: This affects both left- and right-side macrokernels:
trmm_ll, trmm_lu, trmm_rl, trmm_ru.)
- trsm: slab partitioning.
(NOTE: This only affects only left-side macrokernels trsm_ll,
trsm_lu; right-side macrokernels were not touched.)
Also note that the previous macrokernels were preserved inside of
the 'other' directory of each operation family directory (e.g.
frame/3/gemm/other, frame/3/herk/other, etc).
- Updated gemm macrokernel in sandbox/ref99 in light of above changes
and fixed a stale function pointer type in blx_gemm_int.c
(gemm_voft -> gemm_var_oft).
- Added standalone test drivers in test/3m4m for herk, trmm, and trsm
and minor changes to test/3m4m/Makefile.
- Updated the arguments and definitions of bli_*_get_next_[ab]_upanel()
and bli_trmm_?_?r_my_iter() macros defined in bli_l3_thrinfo.h.
- Renamed bli_thread_get_range*() APIs to bli_thread_range*().
Details:
- Rewrote bli_winsys.c to define bli_setenv() and bli_sleep()
unconditionally, but differently for Windows and non-Windows, but
then disabled the definition of bli_setenv() entirely since BLIS
no longer needs to set environment variables. Updated bli_winsys.h
accordingly, and call bli_sleep() from within testsuite instead of
sleep() directly.
- Use
#if !defined(_POSIX_BARRIERS) || (_POSIX_BARRIERS != 200809L)
instead of
#if !defined(_POSIX_BARRIERS) || (_POSIX_BARRIERS < 0)
when guarding against local definition of pthread barrier in
testsuite. (The description for unistd.h implies that _POSIX_BARRIERS
should always be set to 200809L when barriers are supported, though I
won't be surprised if we encounter a case in the future where it is
set to something else such as 1 while still supported.)
- Removed old _VERS_CONF_INST definitions and installation rules in
top-level Makefile. These are no longer needed because we no longer
output libraries with the version and configuration name as
substrings.
- Comment/whitespace updates in Makefile, config.mk.in, common.mk,
configure, bli_extern_defs.h, and test_libblis.h.
- Added mention of 1m to README.md and other trivial tweaks.
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:
- Replaced critical sections that were conditional upon multithreading
being enabled (via pthreads or OpenMP) with unconditional use of
pthreads mutexes. (Why pthreads? Because BLIS already requires it
for its initialization mechanism: pthread_once().) This was done in
bli_error.c, bli_gks.c, bli_l3_ind.c. Also, replaced usage of BLIS's
mtx_t object and bli_mutex_*() API with pthread mutexes in
bli_thread.c. The previous status quo could result in a race condition
if the application called BLIS from more than one thread. The new
pthread-based code should be completely agnostic to the application's
threading configuration. Thanks to AMD for bringing to our attention
the need for a thread-safety review.
- Added an option to the testsuite to simulate application-level
multithreading. Specifically, each thread maintains a counter that is
incremented after each experiment. The thread only executes the
experiment if: counter % n_threads == thread_id. In other words, the
threads simply take turns executing each problem experiment. Also,
POSIX guarantees that fprintf() will not intermingle output, so
output was switched to fprintf() instead of libblis_test_fprintf().
- Changed membrk_t objects to use pthread_mutex_t intead of mtx_t and
replaced use of bli_mutex_init()/_finalize() in bli_membrk.c with
wrappers to pthread_mutex_init()/_destroy().
- Changed the implementation of bli_l3_ind_oper_enable_only() to fix
a race condition; specifically, two threads calling the function with
the same parameters could lead to a non-deterministic outcome.
- Added #include <pthread.h> to bli_cpuid.c and moved the same in
bli_arch.c.
- Added 'const' to declaration of OPT_MARKER in bli_getopt.c.
- Added #include <pthread.h> to bli_system.h.
- Added add-copyright.py script to automate adding new copyright lines
to (and updating existing lines of) source files.
Details:
- Fixed an unused variable warning in frame/base/bli_rntm.c when
multithreading is disabled.
- Fixed a missing variable declaration in bli_thread_init_rntm_from_env()
when multithreading is disabled.
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:
- 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:
- Removed the family field inside the cntx_t struct and re-added it to the
cntl_t struct. Updated all accessor functions/macros accordingly, as well
as all consumers and intermediaries of the family parameter (such as
bli_l3_thread_decorator(), bli_l3_direct(), and bli_l3_prune_*()). This
change was motivated by the desire to keep the context limited, as much
as possible, to information about the computing environment. (The family
field, by contrast, is a descriptor about the operation being executed.)
- Added additional functions to bli_blksz_*() API.
- Added additional functions to bli_cntx_*() API.
- Minor updates to bli_func.c, bli_mbool.c.
- Removed 'obj' from bli_blksz_*() API names.
- Removed 'obj' from bli_cntx_*() API names.
- Removed 'obj' from bli_cntl_*(), bli_*_cntl_*() API names. Renamed routines
that operate only on a single struct to contain the "_node" suffix to
differentiate with those routines that operate on the entire tree.
- Added enums for packm and unpackm kernels to bli_type_defs.h.
- Removed BLIS_1F and BLIS_VF from bszid_t definition in bli_type_defs.h.
They weren't being used and probably never will be.
Details:
- Renamed bli_env_get_nway() -> bli_thread_get_env().
- Added bli_thread_set_env() to allow setting environment variables
pertaining to multithreading, such as BLIS_JC_NT or BLIS_NUM_THREADS.
- Added the following convenience wrapper routines:
bli_thread_get_jc_nt()
bli_thread_get_ic_nt()
bli_thread_get_jr_nt()
bli_thread_get_ir_nt()
bli_thread_get_num_threads()
bli_thread_set_jc_nt()
bli_thread_set_ic_nt()
bli_thread_set_jr_nt()
bli_thread_set_ir_nt()
bli_thread_set_num_threads()
- Added #include "errno.h" to bli_system.h.
- This commit addresses issue #140.
- Thanks to Chris Goodyer for inspiring these updates.
- Number of threads is determined by BLIS_NUM_THREADS or OMP_NUM_THREADS, but can be overridden by BLIS_XX_NT as before.
- Threads are assigned to loops (ic, jc, ir, and jc) automatically by weighted partitioning and heuristics, both of which are tunable via bli_kernel.h.
- All level-3 BLAS covered.
Details:
- Implemented Ricardo Magana's distributed thread info/communicator
management. Rather that fully construct the thrinfo_t structures, from
root to leaf, prior to spawning threads, the threads individually
construct their thrinfo_t trees (or, chains), and do so incrementally,
as needed, reusing the same structure nodes during subsequent blocked
variant iterations. This required moving the initial creation of the
thrinfo_t structure (now, the root nodes) from the _front() functions
to the bli_l3_thread_decorator(). The incremental "growing" of the tree
is performed in the internal back-end (ie: _int()) function, and so
mostly invisible. Also, the incremental growth of the thrinfo_t tree is
done as a function of the current and parent control tree nodes (as well
as the parent thrinfo_t node), further reinforcing the parallel
relationship between the two data structures.
- Removed the "inner" communicator from thrinfo_t structure definition,
as well as its id. Changed all APIs accordingly. Renamed
bli_thrinfo_needs_free_comms() to bli_thrinfo_needs_free_comm().
- Defined bli_l3_thrinfo_print_paths(), which prints the information
in an array of thrinfo_t* structure pointers. (Used only as a
debugging/verification tool.)
- Deprecated the following thrinfo_t creation functions:
bli_packm_thrinfo_create()
bli_l3_thrinfo_create()
because they are no longer used. bli_thrinfo_create() is now called
directly when creating thrinfo_t nodes.
Details:
- Altered control tree node struct definitions so that all nodes have the
same struct definition, whose primary fields consist of a blocksize id,
a variant function pointer, a pointer to an optional parameter struct,
and a pointer to a (single) sub-node. This unified control tree type is
now named cntl_t.
- Changed the way control tree nodes are connected, and what computation
they represent, such that, for example, packing operations are now
associated with nodes that are "inline" in the tree, rather than off-
shoot braches. The original tree for the classic Goto gemm algorithm was
expressed (roughly) as:
blk_var2 -> blk_var3 -> blk_var1 -> ker_var2
| |
-> packb -> packa
and now, the same tree would look like:
blk_var2 -> blk_var3 -> packb -> blk_var1 -> packa -> ker_var2
Specifically, the packb and packa nodes perform their respective packing
operations and then recurse (without any loop) to a subproblem. This means
there are now two kinds of level-3 control tree nodes: partitioning and
non-partitioning. The blocked variants are members of the former, because
they iteratively partition off submatrices and perform suboperations on
those partitions, while the packing variants belong to the latter group.
(This change has the effect of allowing greatly simplified initialization
of the nodes, which previously involved setting many unused node fields to
NULL.)
- Changed the way thrinfo_t tree nodes are arranged to mirror the new
connective structure of control trees. That is, packm nodes are no longer
off-shoot branches of the main algorithmic nodes, but rather connected
"inline".
- Simplified control tree creation functions. Partitioning nodes are created
concisely with just a few fields needing initialization. By contrast, the
packing nodes require additional parameters, which are stored in a
packm-specific struct that is tracked via the optional parameters pointer
within the control tree struct. (This parameter struct must always begin
with a uint64_t that contains the byte size of the struct. This allows
us to use a generic function to recursively copy control trees.) gemm,
herk, and trmm control tree creation continues to be consolidated into
a single function, with the operation family being used to select
among the parameter-agnostic macro-kernel wrappers. A single routine,
bli_cntl_free(), is provided to free control trees recursively, whereby
the chief thread within a groups release the blocks associated with
mem_t entries back to the memory broker from which they were acquired.
- Updated internal back-ends, e.g. bli_gemm_int(), to query and call the
function pointer stored in the current control tree node (rather than
index into a local function pointer array). Before being invoked, these
function pointers are first cast to a gemm_voft (for gemm, herk, or trmm
families) or trsm_voft (for trsm family) type, which is defined in
frame/3/bli_l3_var_oft.h.
- Retired herk and trmm internal back-ends, since all execution now flows
through gemm or trsm blocked variants.
- Merged forwards- and backwards-moving variants by querying the direction
from routines as a function of the variant's matrix operands. gemm and
herk always move forward, while trmm and trsm move in a direction that
is dependent on which operand (a or b) is triangular.
- Added functions bli_thread_get_range_mdim(), bli_thread_get_range_ndim(),
each of which takes additional arguments and hides complexity in managing
the difference between the way ranges are computed for the four families
of operations.
- Simplified level-3 blocked variants according to the above changes, so that
the only steps taken are:
1. Query partitioning direction (forwards or backwards).
2. Prune unreferenced regions, if they exist.
3. Determine the thread partitioning sub-ranges.
<begin loop>
4. Determine the partitioning blocksize (passing in the partitioning
direction)
5. Acquire the curren iteration's partitions for the matrices affected
by the current variants's partitioning dimension (m, k, n).
6. Call the subproblem.
<end loop>
- Instantiate control trees once per thread, per operation invocation.
(This is a change from the previous regime in which control trees were
treated as stateless objects, initialized with the library, and shared
as read-only objects between threads.) This once-per-thread allocation
is done primarily to allow threads to use the control tree as as place
to cache certain data for use in subsequent loop iterations. Presently,
the only application of this caching is a mem_t entry for the packing
blocks checked out from the memory broker (allocator). If a non-NULL
control tree is passed in by the (expert) user, then the tree is copied
by each thread. This is done in bli_l3_thread_decorator(), in
bli_thrcomm_*.c.
- Added a new field to the context, and opid_t which tracks the "family"
of the operation being executed. For example, gemm, hemm, and symm are
all part of the gemm family, while herk, syrk, her2k, and syr2k are
all part of the herk family. Knowing the operation's family is necessary
when conditionally executing the internal (beta) scalar reset on on
C in blocked variant 3, which is needed for gemm and herk families,
but must not be performed for the trmm family (because beta has only
been applied to the current row-panel of C after the first rank-kc
iteration).
- Reexpressed 3m3 induced method blocked variant in frame/3/gemm/ind
to comform with the new control tree design, and renamed the macro-
kernel codes corresponding to 3m2 and 4m1b.
- Renamed bli_mem.c (and its APIs) to bli_memsys.c, and renamed/relocated
bli_mem_macro_defs.h from frame/include to frame/base/bli_mem.h.
- Renamed/relocated bli_auxinfo_macro_defs.h from frame/include to
frame/base/bli_auxinfo.h.
- Fixed a minor bug whereby the storage-to-ukr-preference matching
optimization in the various level-3 front-ends was not being applied
properly when the context indicated that execution would be via an
induced method. (Before, we always checked the native micro-kernel
corresponding to the datatype being executed, whereas now we check
the native micro-kernel corresponding to the datatype's real projection,
since that is the micro-kernel that is actually used by induced methods.
- Added an option to the testsuite to skip the testing of native level-3
complex implementations. Previously, it was always tested, provided that
the c/z datatypes were enabled. However, some configurations use
reference micro-kernels for complex datatypes, and testing these
implementations can slow down the testsuite considerably.
Details:
- These changes constitute the first set of changes in preparation to
revamping the structure and use of control trees in BLIS. Modifications
in this commit don't affect the control tree code yet, but rather lay
the groundwork.
- Defined wrappers for the following functions, where the the wrappers
each take a direction parameter of a new enumerated type (BLIS_BWD or
BLIS_FWD), dir_t, and executes the correct underlying function.
- bli_acquire_mpart_*() and _vpart_*()
- bli_*_determine_kc_[fb]()
- bli_thread_get_range_*() and bli_thread_get_range_weighted_*()
- Consolidated all 'f' (forwards-moving) and 'b' (backwards-moving)
blocked variants for trmm and trsm, and renamed gemm and herk variants
accordingly. The direction is now queried via routines such as
bli_trmm_direct(), which deterines the direction from the implied side
and uplo parameters. For gemm and herk, it is uncondtionally BLIS_FWD.
- Defined wrappers to parameter-specific macrokernels for herk, trmm, and
trsm, e.g. bli_trmm_xx_ker_var2(), that execute the correct underlying
macrokernel based on the implied parameters. The same logic used to
choose the dir_t in _direct() functions is used here.
- Simplified the function pointer arrays in _int() functions given the
consolidation and dir_t querying mentioned above.
- Function signature (whitespace) reformatting for various functions.
- Removed old code in various 'old' directories.
Details:
- Reorganized code and renamed files defining APIs related to multithreading.
All code that is not specific to a particular operation is now located in a
new directory: frame/thread. Code is now organized, roughly, by the
namespace to which it belongs (see below).
- Consolidated all operation-specific *_thrinfo_t object types into a single
thrinfo_t object type. Operation-specific level-3 *_thrinfo_t APIs were
also consolidated, leaving bli_l3_thrinfo_*() and bli_packm_thrinfo_*()
functions (aside from a few general purpose bli_thrinfo_*() functions).
- Renamed thread_comm_t object type to thrcomm_t.
- Renamed many of the routines and functions (and macros) for multithreading.
We now have the following API namespaces:
- bli_thrinfo_*(): functions related to thrinfo_t objects
- bli_thrcomm_*(): functions related to thrcomm_t objects.
- bli_thread_*(): general-purpose functions, such as initialization,
finalization, and computing ranges. (For now, some macros, such as
bli_thread_[io]broadcast() and bli_thread_[io]barrier() use the
bli_thread_ namespace prefix, even though bli_thrinfo_ may be more
appropriate.)
- Renamed thread-related macros so that they use a bli_ prefix.
- Renamed control tree-related macros so that they use a bli_ prefix (to be
consistent with the thread-related macros that were also renamed).
- Removed #undef BLIS_SIMD_ALIGN_SIZE from dunnington's bli_kernel.h. This
#undef was a temporary fix to some macro defaults which were being applied
in the wrong order, which was recently fixed.
