Two-level distributed barrier is a new experimental barrier designed
for Intel hardware that has better performance in some cases than the
default hyper barrier.

This barrier is designed to handle fine granularity parallelism where
barriers are used frequently with little compute and memory access
between barriers. There is no need to use it for codes with few
barriers and large granularity compute, or memory intensive
applications, as little difference will be seen between this barrier
and the default hyper barrier. This barrier is designed to work
optimally with a fixed number of threads, and has a significant setup
time, so should NOT be used in situations where the number of threads
in a team is varied frequently.

The two-level distributed barrier is off by default -- hyper barrier
is used by default. To use this barrier, you must set all barrier
patterns to use this type, because it will not work with other barrier
patterns. Thus, to turn it on, the following settings are required:

KMP_FORKJOIN_BARRIER_PATTERN=dist,dist
KMP_PLAIN_BARRIER_PATTERN=dist,dist
KMP_REDUCTION_BARRIER_PATTERN=dist,dist

Branching factors (set with KMP_FORKJOIN_BARRIER, KMP_PLAIN_BARRIER,
and KMP_REDUCTION_BARRIER) are ignored by the two-level distributed
barrier.

Patch fixed for ITTNotify disabled builds and non-x86 builds

Co-authored-by: Jonathan Peyton <jonathan.l.peyton@intel.com>
Co-authored-by: Vladislav Vinogradov <vlad.vinogradov@intel.com>

Differential Revision: https://reviews.llvm.org/D103121

This reverts commit 25073a4ecfc9b2e3cb76776185e63bfdb094cd98.

This breaks non-x86 OpenMP builds for a while now. Until a solution is
ready to be upstreamed we revert the feature and unblock those builds.
See:
  https://reviews.llvm.org/rG25073a4ecfc9b2e3cb76776185e63bfdb094cd98#1005821
and
  https://reviews.llvm.org/rG25073a4ecfc9b2e3cb76776185e63bfdb094cd98#1005821

The currently proposed fix (D104788) seems not to be ready yet:
  https://reviews.llvm.org/D104788#2841928

Two-level distributed barrier is a new experimental barrier designed
for Intel hardware that has better performance in some cases than the
default hyper barrier.

This barrier is designed to handle fine granularity parallelism where
barriers are used frequently with little compute and memory access
between barriers.  There is no need to use it for codes with few
barriers and large granularity compute, or memory intensive
applications, as little difference will be seen between this barrier
and the default hyper barrier. This barrier is designed to work
optimally with a fixed number of threads, and has a significant setup
time, so should NOT be used in situations where the number of threads
in a team is varied frequently.

The two-level distributed barrier is off by default -- hyper barrier
is used by default. To use this barrier, you must set all barrier
patterns to use this type, because it will not work with other barrier
patterns.  Thus, to turn it on, the following settings are required:

KMP_FORKJOIN_BARRIER_PATTERN=dist,dist
KMP_PLAIN_BARRIER_PATTERN=dist,dist
KMP_REDUCTION_BARRIER_PATTERN=dist,dist

Branching factors (set with KMP_FORKJOIN_BARRIER, KMP_PLAIN_BARRIER,
and KMP_REDUCTION_BARRIER) are ignored by the two-level distributed
barrier.

Differential Revision: https://reviews.llvm.org/D103121

These changes add support for Intel's umonitor/umwait usage in wait
code, for architectures that support those intrinsic functions. Usage of
umonitor/umwait is off by default, but can be turned on by setting the
KMP_USER_LEVEL_MWAIT environment variable.

Differential Revision: https://reviews.llvm.org/D91189

This reverts commit 9cfad5f9c5bfd985f1bc8b0954f58013c5236e58.

Patch by tlwilmar (Terry Wilmarth)

Differential Revision: https://reviews.llvm.org/D91189

to reflect the new license. These used slightly different spellings that
defeated my regular expressions.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351648

This change fixes possibly invalid access to the internal data structure during
library shutdown.  In a heavily oversubscribed situation, the library shutdown
sequence can reach the point where resources are deallocated while there still
exist threads in their final spinning loop.  The added loop in
__kmp_internal_end() checks if there are such busy-waiting threads and blocks
the shutdown sequence if that is the case. Two versions of kmp_wait_template()
are now used to minimize performance impact.

Patch by Hansang Bae

Differential Revision: https://reviews.llvm.org/D49452

llvm-svn: 337486

.clang-format's comments are removed and a (hopefully) final
set of formatting changes are applied.

Differential Revision: https://reviews.llvm.org/D38837
Differential Revision: https://reviews.llvm.org/D38920

llvm-svn: 316227

This patch contains the clang-format and cleanup of the entire code base. Some
of clang-formats changes made the code look worse in places. A best effort was
made to resolve the bulk of these problems, but many remain. Most of the
problems were mangling line-breaks and tabbing of comments.

Patch by Terry Wilmarth

Differential Revision: https://reviews.llvm.org/D32659

llvm-svn: 302929