Details:
- Added a new sub-configuration 'cortexa53', which is a mirror image
of cortexa57 except that it will use slightly different compiler
flags. Thanks to Mathieu Poumeyrol for making this suggestion after
discovering that the compiler flags being used by cortexa57 were
not working properly in certain OS X environments (the fix to which
is currently pending in pull request #245).
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:
- Added logic to bli_arch.c that will call what was previously the body
of bli_arch_query_id() only once and then cache the value in a static
variable local to the file. (Previously, the arch_t associated with
the hardware/configuration was queried every time bli_arch_query_id()
was called, which was at least once per level-3 function call. Thanks
to Devin Matthews for suggesting this feature via issue #175.
- Added -lpthread to the compile/link command line of the compiler
invocation that compiles build/detect/config/config_detect.c, which
prints the string identifying the detected configuration, since it
is now needed due to new pthread_once() logic in bli_arch.c.
- Implementation note: I chose to implement this arch_t caching feature
via pthread_once(), using a separate pthread_once_t variable local to
the file, rather than calling bli_init_once(). The reason is that I
did not want to require bli_init() as a prerequisite to this function.
bli_init() already calls several sub-components, some of which make use
of bli_arch_query_id(), and therefore it would be easy to fall into a
circular self-init situation (which usually causes pthreads to hang
indefinitely).
Details:
- Updated/clarified the ARM preprocessor macro branch of bli_cpuid.c.
Going forward, cortexa57 (64-bit), cortexa15, and cortexa9 (32-bit)
sub-configurations are supported. However, the functions that detect
features specific to a15 and a9 are identical, and since a15 is tested
first, it will always be chosen for arm32 hardware (even if both
sub-configurations were enabled at configure-time and the library is
linked and run on an a9). Thus, more work needs to be done to
distinguish these two.
- Added cpp guard around x86_64 portions of bli_cpuid.c. Now, either
the x86_64 or ARM code will be compiled (or neither, if neither
environment is detected).
- In bli_arch_query_id(), call bli_cpuid_query_id() when the
BLIS_FAMILY_ARM64 or BLIS_FAMILY_ARM32 macros are defined.
- Added arm64 and arm32 configuration families to config_registry.
- Added a note to the arch_t typedef enum in bli_type_defs.h reminding
the developer to update the string array in bli_arch.c whenever new
enum values are added or existing values are reordered.
Details:
- Added "-std=c99" to compiler arguments when building auto-detection
driver in configure script.
- Added #include <stdint.h> to all three source files needed by auto-
detection program.
Details:
- Reimplemented the hardware detection functionality invoked when running
"./configure auto". Previously, a standalone script in build/auto-detect
that used CPUID was used. However, the script attempted to enumerate all
models for each microarchitecture supported. The new approach recycles
the same code used for runtime hardware detection introduced in 2c51356.
This has two immediate benefits. First, it reduces and consolidates the
code required to detect microarchitectures via the CPUID instruction.
Second, it provides an indirect way of testing at configure-time the
code that is used to detect hardware at runtime. This code is (a) only
activated when targeting a configuration family (such as intel64 or
amd64) at configure-time and (b) somewhat difficult to test in
practice, since it relies on having access to older microarchitectures.
- The above change required placing conditional cpp macro blocks in
bli_arch.c and bli_cpuid.c which either #include "blis.h" or #include
a bare-bones set of headers that does not rely on the presence of a
bli_config.h header. This is needed because bli_config.h has not been
created yet when configure-time auto-detection takes places.
- Defined a new function in bli_arch.c, bli_arch_string(), which takes
an arch_t id and returns a pointer to a string that contains the
lowercase name of the corresponding microarchitecture. This function
is used by the auto-detection script to printf() the name of the
sub-configuration corresponding to the detected hardware.
Details:
- Added support for the x86_64 configuration family to bli_arch.c and
bli_arch_config.h. Thanks to Johannes Dieterich for reporting this
issue.
- Bumped the default value for BLIS_SIMD_NUM_REGISTERS from 16 to 32 and
the default value for BLIS_SIMD_SIZE from 32 to 64. This will support
configuration families that include Skylake and newer processors without
any supported needed in the bli_family_*.h file. The semantics of these
values have always been "maximum" and not exact values; comments in
bli_kernel_macro_defs.h and the github wiki have been adjusted
accordingly.
Details:
- Added runtime support for selecting an appropriate arch_t value based
on the results of the cpuid instruction (for x86_64). This allows
deferral of choosing a context (kernels, blocksizes, etc.) until
runtime, which allows BLIS to be built with support for multiple
microarchitectures. Currently, only amd64 and intel64 configurations
are registered in the config_registry; however, one could create
custom configuration families to support arbitrary sets of x86_64
microarchitectures.
- Current Intel microarchitectures supported via cpuid are knl, haswell,
sandybridge, and penryn.
- Current AMD microarchitectures supported via cpuid are: zen, excavator,
steamroller, piledriver, and bulldozer.
Details:
- Added a "generic" configuration that leaves the default blocksizes and
kernels unchanged. This replaces the older "reference" configuration.
Updated auto-detect script and code accordingly.
- Added support for generic configuration to arch_t (bli_type_defs.h),
bli_gks_init() (bli_gks.c), and bli_arch_config.h
- Moved bli_arch_query_id() to bli_arch.c (and prototype to bli_arch.h).
- Whitespace changes to configurations' make_defs.mk files.
