llvm-svn: 273438

OpenMP 4.1 is now OpenMP 4.5.  Any mention of 41 or 4.1 is replaced with
45 or 4.5.  Also, if the CMake option LIBOMP_OMP_VERSION is 41, CMake warns that
41 is deprecated and to use 45 instead.

llvm-svn: 272687

MSVC doesn't allow std::atomic<>s in a union since they don't have trivial
copy constructor. Replacing them with e.g. std::atomic_int works, but that
breaks the GCC build on Linux, because then calls to e.g. std::atomic_load_explicit
fail, as they expect a real std::atomic<> pointer.

Fixing this with an #ifdef to unbreak the build for now.

llvm-svn: 272271

This patch replaces use of compiler builtin atomics with
C++11 atomics for ticket locks implementation. Ticket locks
are used in critical places of the runtime, e.g. in the tasking
mechanism.

The main reason this change was introduced is the problem
with work stealing function on ARM architecture which suffered
from nasty race condition. It turned out that the root cause of
the problem lies in the way ticket locks are implemented. Changing
compiler builtins into C++11 atomics solves the problem.

Two assertions were added into kmp_tasking.c which are useful
for detecting early symptoms of something wrong going on with
work stealing, which were among the possible outcomes of the
race condition.

Differential Revision: http://reviews.llvm.org/D19878

llvm-svn: 271324

This patch doesn't affect D19878's context.  So D19878 still cleanly applies.

llvm-svn: 270252

This change adds back off logic in the test and set lock for better contended
lock performance. It uses a simple truncated binary exponential back off
function. The default back off parameters are tuned for x86.

The main back off logic has a two loop structure where each is controlled by a
user-level parameter:
max_backoff - limits the outer loop number of iterations.
    This parameter should be a power of 2.
min_ticks - the inner spin wait loop number of "ticks" which is system
    dependent and should be tuned for your system if you so choose.
    The "ticks" on x86 correspond to the time stamp counter,
    but on other architectures ticks is a timestamp derived
    from gettimeofday().

The user can modify these via the environment variable:
KMP_SPIN_BACKOFF_PARAMS=max_backoff[,min_ticks]
Currently, since the default user lock is a queuing lock,
one would have to also specify KMP_LOCK_KIND=tas to use the test-and-set locks.

Differential Revision: http://reviews.llvm.org/D19020

llvm-svn: 266329

This change set includes all changes to make the code conform to the OMP 4.5 specification:

* Removed hint / hinted_init definitions from include/40 files
* Hint values are powers of 2 to enable composition (4.5 spec)
* Hinted lock initialization functions were renamed (4.5 spec)
  kmp_init_lock_hinted -> omp_init_lock_with_hint
  kmp_init_nest_lock_hinted -> omp_init_nest_lock_with_hint
* __kmpc_critical_section_with_hint was added to support a critical section with
  a hint (4.5 spec)
* __kmp_map_hint_to_lock was added to convert a hint (possibly a composite) to
  an internal lock type
* kmpc_init_lock_with_hint and kmpc_init_nest_lock_with_hint were added as
  internal entries for the hinted lock initializers. The preivous internal
  functions (__kmp_init*) were moved to kmp_csupport.c and reused in multiple
  places
* Added the two init functions to dllexports
* KMP_USE_DYNAMIC_LOCK is turned on if OMP_41_ENABLED is turned on

Differential Revision: http://reviews.llvm.org/D15205

llvm-svn: 255376

* Added a new user TSX lock implementation, RTM, This implementation is a
  light-weight version of the adaptive lock implementation, omitting the
  back-off logic for deciding when to specualte (or not). The fall-back lock is
  still the queuing lock.
* Changed indirect lock table management. The data for indirect lock management
  was encapsulated in the "kmp_indirect_lock_table_t" type. Also, the lock table
  dimension was changed to 2D (was linear), and each entry is a
  kmp_indirect_lock_t object now (was a pointer to an object).
* Some clean up in the critical section code
* Removed the limits of the tuning parameters read from KMP_ADAPTIVE_LOCK_PROPS
* KMP_USE_DYNAMIC_LOCK=1 also turns on these two switches:
  KMP_USE_TSX, KMP_USE_ADAPTIVE_LOCKS

Differential Revision: http://reviews.llvm.org/D15204

llvm-svn: 255375

There are going to be two more patches which bring this feature up to date and in line with OpenMP 4.5.

* Renamed jump tables for the lock functions (and some clean up).
* Renamed some macros to be in KMP_ namespace.
* Return type of unset functions changed from void to int.
* Enabled use of _xebgin() et al. intrinsics for accessing TSX instructions.

Differential Revision: http://reviews.llvm.org/D15199

llvm-svn: 255373

llvm-svn: 254637

This fix implements the following OMPT events for the API locking routines:
* ompt_event_acquired_lock
* ompt_event_acquired_nest_lock_first
* ompt_event_acquired_nest_lock_next
* ompt_event_init_lock
* ompt_event_init_nest_lock
* ompt_event_destroy_lock
* ompt_event_destroy_nest_lock

For the acquired events the depths of the locks ist required, so a return value
was added similiar to the return values we already have for the release lock
routines.

Patch by Tim Cramer

Differential Revision: http://reviews.llvm.org/D13689

llvm-svn: 250526

This is a preparation patch to get information about the actual release status from nested locks for OMPT.

llvm-svn: 236114

llvm-svn: 230030

llvm-svn: 227207

llvm-svn: 225792

understand that this is not friendly, and are working to change our
internal code-development to make it easier to make development
features available more frequently and in finer (more functional)
chunks. Unfortunately we haven't got that in place yet, and unpicking
this into multiple separate check-ins would be non-trivial, so please
bear with me on this one. We should be better in the future.

Apologies over, what do we have here?

GGC 4.9 compatibility
--------------------
* We have implemented the new entrypoints used by code compiled by GCC
4.9 to implement the same functionality in gcc 4.8. Therefore code
compiled with gcc 4.9 that used to work will continue to do so.
However, there are some other new entrypoints (associated with task
cancellation) which are not implemented. Therefore user code compiled
by gcc 4.9 that uses these new features will not link against the LLVM
runtime. (It remains unclear how to handle those entrypoints, since
the GCC interface has potentially unpleasant performance implications
for join barriers even when cancellation is not used)

--- new parallel entry points ---
new entry points that aren't OpenMP 4.0 related
These are implemented fully :-
      GOMP_parallel_loop_dynamic()
      GOMP_parallel_loop_guided()
      GOMP_parallel_loop_runtime()
      GOMP_parallel_loop_static()
      GOMP_parallel_sections()
      GOMP_parallel()

--- cancellation entry points ---
Currently, these only give a runtime error if OMP_CANCELLATION is true
because our plain barriers don't check for cancellation while waiting
        GOMP_barrier_cancel()
        GOMP_cancel()
        GOMP_cancellation_point()
        GOMP_loop_end_cancel()
        GOMP_sections_end_cancel()

--- taskgroup entry points ---
These are implemented fully.
      GOMP_taskgroup_start()
      GOMP_taskgroup_end()

--- target entry points ---
These are empty (as they are in libgomp)
     GOMP_target()
     GOMP_target_data()
     GOMP_target_end_data()
     GOMP_target_update()
     GOMP_teams()

Improvements in Barriers and Fork/Join
--------------------------------------
* Barrier and fork/join code is now in its own file (which makes it
easier to understand and modify).
* Wait/release code is now templated and in its own file; suspend/resume code is also templated
* There's a new, hierarchical, barrier, which exploits the
cache-hierarchy of the Intel(r) Xeon Phi(tm) coprocessor to improve
fork/join and barrier performance.

***BEWARE*** the new source files have *not* been added to the legacy
Cmake build system. If you want to use that fixes wil be required.

Statistics Collection Code
--------------------------
* New code has been added to collect application statistics (if this
is enabled at library compile time; by default it is not). The
statistics code itself is generally useful, the lightweight timing
code uses the X86 rdtsc instruction, so will require changes for other
architectures.
The intent of this code is not for users to tune their codes but
rather 
1) For timing code-paths inside the runtime
2) For gathering general properties of OpenMP codes to focus attention
on which OpenMP features are most used. 

Nested Hot Teams
----------------
* The runtime now maintains more state to reduce the overhead of
creating and destroying inner parallel teams. This improves the
performance of code that repeatedly uses nested parallelism with the
same resource allocation. Set the new KMP_HOT_TEAMS_MAX_LEVEL
envirable to a depth to enable this (and, of course, OMP_NESTED=true
to enable nested parallelism at all).

Improved Intel(r) VTune(Tm) Amplifier support
---------------------------------------------
* The runtime provides additional information to Vtune via the
itt_notify interface to allow it to display better OpenMP specific
analyses of load-imbalance.

Support for OpenMP Composite Statements
---------------------------------------
* Implement new entrypoints required by some of the OpenMP 4.1
composite statements.

Improved ifdefs
---------------
* More separation of concepts ("Does this platform do X?") from
platforms ("Are we compiling for platform Y?"), which should simplify
future porting.


ScaleMP* contribution
---------------------
Stack padding to improve the performance in their environment where
cross-node coherency is managed at the page level.

Redesign of wait and release code
---------------------------------
The code is simplified and performance improved.

Bug Fixes
---------
    *Fixes for Windows multiple processor groups.
    *Fix Fortran module build on Linux: offload attribute added.
    *Fix entry names for distribute-parallel-loop construct to be consistent with the compiler codegen.
    *Fix an inconsistent error message for KMP_PLACE_THREADS environment variable.

llvm-svn: 219214

llvm-svn: 215093

llvm-svn: 202018

This release use aligns with Intel(r) Composer XE 2013 SP1 Product Update 2 

New features
* The library can now be built with clang (though wiht some
  limitations since clang does not support 128 bit floats)
* Support for Vtune analysis of load imbalance
* Code contribution from Steven Noonan to build the runtime for ARM*
  architecture processors 
* First implementation of runtime API for OpenMP cancellation

Bug Fixes
* Fixed hang on Windows (only) when using KMP_BLOCKTIME=0

llvm-svn: 197914

llvm-svn: 191506