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10 Commits
| Author | SHA1 | Message | Date | |
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kdevraje
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13806ba3b0 |
This check in has changes w.r.t Copyright information, which is changed to (start year) - 2019
Change-Id: Ide3c8f7172210b8d3538d3c36e88634ab1ba9041 |
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Field G. Van Zee
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2f3174330f |
Implemented a pool-based small block allocator.
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
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Field G. Van Zee
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76016691e2 |
Improvements to bli_pool; malloc()/free() tracing.
Details:
- Added malloc_ft and free_ft fields to pool_t, which are provided when
the pool is initialized, to allow bli_pool_alloc_block() and
bli_pool_free_block() to call bli_fmalloc_align()/bli_ffree_align()
with arbitrary align_size values (according to how the pool_t was
initialized).
- Added a block_ptrs_len argument to bli_pool_init(), which allows the
caller to specify an initial length for the block_ptrs array, which
previously suffered the cost of being reallocated, copied, and freed
each time a new block was added to the pool.
- Consolidated the "buf_sys" and "buf_align" pointer fields in pblk_t
into a single "buf" field. Consolidated the bli_pblk API accordingly
and also updated the bli_mem API implementation. This was done
because I'd previously already implemented opaque alignment via
bli_malloc_align(), which allocates extra space and stores the
original pointer returned by malloc() one element before the element
whose address is aligned.
- Tweaked bli_membrk_acquire_m() and bli_membrk_release() to call
bli_fmalloc_align() and bli_ffree_align(), which required adding an
align_size field to the membrk_t struct.
- Pass the pack schemas directly into bli_l3_cntl_create_if() rather
than transmit them via objects for A and B.
- Simplified bli_l3_cntl_free_if() and renamed to bli_l3_cntl_free().
The function had not been conditionally freeing control trees for
quite some time. Also, removed obj_t* parameters since they aren't
needed anymore (or never were).
- Spun-off OpenMP nesting code in bli_l3_thread_decorator() to a
separate function, bli_l3_thread_decorator_thread_check().
- Renamed:
bli_malloc_align() -> bli_fmalloc_align()
bli_free_align() -> bli_ffree_align()
bli_malloc_noalign() -> bli_fmalloc_noalign()
bli_free_noalign() -> bli_ffree_noalign()
The 'f' is for "function" since they each take a malloc_ft or free_ft
function pointer argument.
- Inserted various printf() calls for the purposes of tracing memory
allocation and freeing, guarded by cpp macro ENABLE_MEM_DEBUG, which,
for now, is intended to be a "hidden" feature rather than one hooked
up to a configure-time option.
- Defined bli_rntm_equals(), which compares two rntm_t for equality.
(There are no use cases for this function yet, but there may be soon.)
- Whitespace changes to function parameter lists in bli_pool.c, .h.
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Field G. Van Zee
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0645f239fb |
Remove UT-Austin from copyright headers' clause 3.
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.
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Field G. Van Zee
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4fa4cb0734 |
Trivial comment header updates.
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. |
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Field G. Van Zee
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ecbebe7c2e |
Defined rntm_t to relocate cntx_t.thrloop (#235).
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. |
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Field G. Van Zee
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4b36e85be9 |
Converted function-like macros to static functions.
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). |
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Field G. Van Zee
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b01c808299 |
Fixed a minor bug in level-3 packm management.
Details: - Fixed a bug in bli_l3_packm() that caused cntl_t-cached packed mem_t entries to be released and then re-acquired unnecessarily. (In essence, the "<" operands in the conditional that guards the release-and-reacquire code block simply needed to be swapped.) The bug should have only affected performance (rather than the computed result). Thanks to Minh Quan for identifying and reporting the bug. |
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Field G. Van Zee
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35509818cb |
Added, moved some thread barriers.
Details: - Removed thread barriers from the end of the loop bodies of bli_gemm_blk_var1(), bli_gemm_blk_var2(), bli_trsm_blk_var1(), and bli_trsm_blk_var2(). - Moved the thread barrier at the end of bli_packm_int() to the end of bli_l3_packm(), and added missing barriers to that function. - Removed the no longer necessary (and now incorrect) ochief guard in bli_gemm3m3_packa() on the bli_obj_scalar_reset() on C. - Thanks to Tyler Smith for help with these changes. |
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Field G. Van Zee
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701b9aa3ff |
Redesigned control tree infrastructure.
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
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-> 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.
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