This change fixes the implementation of OMP_THREAD_LIMIT. The implementation of
this previously was not restricted to a contention group (but it should be,
according to the spec), and this is fixed here. A field is added to root thread
to store a counter of the threads in the contention group. An extra check is
added when reserving threads for a parallel region that checks this variable and
compares to threadlimit-var, which is implemented as a new global variable,
kmp_cg_max_nth. Associated settings changes were also made, and clean up of
comments that referred to OMP_THREAD_LIMIT, but should refer to the new
KMP_DEVICE_THREAD_LIMIT (added in an earlier patch).
Patch by Terry Wilmarth
Differential Revision: https://reviews.llvm.org/D35912
llvm-svn: 309319
With these settings, the create_hwloc_map() method was being called causing an
assert(). After some consideration, it was determined that disabling affinity
explicitly should just disable hwloc as well. i.e., KMP_AFFINITY overrides
KMP_TOPOLOGY_METHOD. This lets the user know that the Hwloc mechanism is being
ignored when KMP_AFFINITY=disabled.
Differential Revision: https://reviews.llvm.org/D33208
llvm-svn: 304344
The problem is the lack of dispatch buffers when thousands of loops with nowait,
about 10 iterations each, are executed by hundreds of threads. We only have
built-in 7 dispatch buffers, but there is a need in dozens or hundreds of
buffers.
The problem can be fixed by setting KMP_MAX_DISP_BUF to bigger value. In order
to give users same possibility I changed build-time control into run-time one,
adding API just in case.
This change adds an environment variable KMP_DISP_NUM_BUFFERS and a new API
function kmp_set_disp_num_buffers(int num_buffers).
The KMP_DISP_NUM_BUFFERS envirable works only before serial initialization,
because during the serial initialization we already allocate buffers for the hot
team, so it is too late to change the number of buffers later (or we need to
reallocate buffers for all teams which sounds too complicated). The
kmp_set_defaults() routine does not work for this envirable, because it calls
serial initialization before reading the parameter string. So a new routine,
kmp_set_disp_num_buffers(), is created so that it can set our internal global
variable before the library initialization. If both the envirable and API used
the envirable wins.
Differential Revision: http://reviews.llvm.org/D20697
llvm-svn: 271318
This change has OMP_WAIT_POLICY=active to mean that threads will busy-wait in
spin loops and virtually never go to sleep. OMP_WAIT_POLICY=passive now means
that threads will immediately go to sleep inside a spin loop. KMP_BLOCKTIME was
the previous mechanism to specify this behavior via KMP_BLOCKTIME=0 or
KMP_BLOCKTIME=infinite, but the standard OpenMP environment variable should
also be able to specify this behavior.
Differential Revision: http://reviews.llvm.org/D18577
llvm-svn: 265339
Jonathan Peyton