In: http://lists.llvm.org/pipermail/openmp-dev/2015-August/000858.html, a
performance issue was found with libomp's task dependencies. The task
dependencies hash table has an issue with collisions. The current table size is
a power of two. This combined with the current hash function causes a large
number of collisions to occurr. Also, the current size (64) is too small for
larger applications so the table size is increased.
This patch creates a two level hash table approach for task dependencies. The
implicit task is considered the "master" or "top-level" task which has a large
static sized hash table (997), and nested tasks will have smaller hash
tables (97). Prime numbers were chosen to help reduce collisions.
Differential Revision: http://reviews.llvm.org/D16640
llvm-svn: 259113
The attached patch adds support for ompt_event_task_dependences and
ompt_event_task_dependence_pair events from the OMPT specification [1]. These
events only apply to OpenMP 4.0 and 4.1 (aka 4.5) because task dependencies
were introduced in 4.0.
With respect to the changes:
ompt_event_task_dependences
According to the specification, this event is raised after the task has been
created, thefore this event needs to be raised after ompt_event_task_begin
(in __kmp_task_start). However, the dependencies are known at
__kmpc_omp_task_with_deps which occurs before __kmp_task_start. My modifications
extend the ompt_task_info_t struct in order to store the dependencies of the
task when _kmpc_omp_task_with_deps occurs and then they are emitted in
__kmp_task_start just after raising the ompt_event_task_begin. The deps field
is allocated and valid until the event is raised and it is freed and set
to null afterwards.
ompt_event_task_dependence_pair
The processing of the dependences (i.e. checking whenever a dependence is
already satisfied) is done within __kmp_process_deps. That function checks
every dependence and calls the __kmp_track_dependence routine which gives some
support for graphical output. I used that routine to emit the dependence pair
but I also needed to know the sink_task. Despite the fact that the code within
KMP_SUPPORT_GRAPH_OUTPUT refers to task_sink it may be null because
sink->dn.task (there's a comment regarding this) and in fact it does not point
to a proper pointer value because the value is set in node->dn.task = task;
after the __kmp_process_deps calls in __kmp_check_deps. I have extended the
__kmp_process_deps and __kmp_track_dependence parameter list to receive the
sink_task.
[1] https://github.com/OpenMPToolsInterface/OMPT-Technical-Report/blob/target/ompt-tr.pdf
Patch by Harald Servat
Differential Revision: http://reviews.llvm.org/D14746
llvm-svn: 259038
When the code behind the barrier is executed, the master thread may have
already resumed execution. That's why we cannot safely assume that *pteam
is not yet freed.
This has been introduced by r258866.
llvm-svn: 259037
Current clang trunk reports _OPENMP to be 201307 = OpenMP 4.0. It doesn't
recognize '#pragma omp declare target' though (patch still pending) and
therefore fails compilation.
Differential Revision: http://reviews.llvm.org/D16631
llvm-svn: 259026
For implcit barriers in simple parallel for loops, the order of the OMPT events
was wrong. The barrier_{begin,end} events came after the implcit_task_end
event for the implcit barrier at the end of the parallel region. This is wrong
because the implicit task executes the barrier before ending. This patch fixes
the order of the event: It will be triggerd now just before
__kmp_pop_current_task_from_thread() is called.
Patch by Tim Cramer
Differential Revision: http://reviews.llvm.org/D16347
llvm-svn: 258866
This change fixes the bug: https://llvm.org/bugs/show_bug.cgi?id=25975
by bypassing the perl module files which try to deduce system information.
These perl modules files don't offer useful information and are from the
original build system. They can be removed after this change.
llvm-svn: 258843
This change fixes one issue reported at https://llvm.org/bugs/show_bug.cgi?id=26184
There was missing cleanup code for the cached indirect lock pool. The change
will fix the reported case where it tries to initialize a lock after runtime
cleanup/reinitialization, but it is still possible that the user program runs
into another problem because most test programs have a call to __kmpc_set_lock
after cleanup/reinitialization without calling __kmpc_init_lock causing a crash/hang.
llvm-svn: 258528
The release builds are configured to be reproducible, so that the
binaries compare equal between bootstrap iterations. The OpenMP
run-time build was failing like this:
runtime/src/kmp_version.c:108:79: error: expansion of date or time macro is not reproducible [-Werror,-Wdate-time]
char const __kmp_version_build_time[] = KMP_VERSION_PREFIX "build time: " __DATE__ " " __TIME__;
Figuring as the build currently doesn't set LIBOMP_DATE, it's probably
OK to skip setting the build time here too.
llvm-svn: 257833
This new API, int kmp_set_thread_affinity_mask_initial(), is available for use
by other parallel runtime libraries inside a possibly OpenMP-registered thread.
This entry point restores the current thread's affinity mask to the affinity
mask of the application when it first began. If -1 is returned it can be assumed
that either the thread hasn't called affinity initialization or that the thread
isn't registered with the OpenMP library. If 0 is returned then, then the call
was successful. Any return value greater than zero indicates an error occurred
when setting affinity.
Differential Revision: http://reviews.llvm.org/D15867
llvm-svn: 257489
Recent changes to support dynamic locks didn't consider the code compiled when
OMPT_SUPPORT=true. As a result, the OMPT support was broken by recent changes
to nested locks to support dynamic locks. For OMPT to work with dynamic locks,
they need to provide a return code indicating whether a nested lock acquisition
was the first or not.
This patch moves the OMPT support for nested locks into the #else case when
DYNAMIC locks were not used. New support is needed for dynamic locks. This patch
fixes the build and leaves a placeholder where the missing OMPT callbacks can be
added either the author of the OMPT support for locks, or the dynamic
locking support.
Patch by John Mellor-Crummey
Differential Revision: http://reviews.llvm.org/D15656
llvm-svn: 256314
When users sets envirable KMP_BLOCKTIME to "infinite" (the time one busy-waits
at barrieres, etc.), the monitor thread is not useful and can be ignored. This
change prevents the creation of the monitor thread when the users sets
KMP_BLOCKTIME to "infinite".
Differential Revision: http://reviews.llvm.org/D15628
llvm-svn: 256061
This change allows clang to build the stats library for every architecture
which supports __builtin_readcyclecounter(). CMake also checks for all
necessary features for stats and will error out if the platform does not
support it.
Patch by Hal Finkel and Johnny Peyton
llvm-svn: 256002
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
Fix for crash in the teams construct in case user sets OMP_THREAD_LIMIT to a
number less than the number of processors. Now the number of threads will be
silently reduced if the user didn't specify teams parameters or with a
warning if the user specified teams parameters conflicting with
OMP_THREAD_LIMIT.
Differential Revision: http://reviews.llvm.org/D14732
llvm-svn: 254322
The task_team pointer is dereferenced unconditionally which causes a SEGFAULT
when it is NULL (e.g. for serialized parallel, that can happen for "teams"
construct or for "target nowait"). The solution is to skip second task team
setup for single thread team.
Differential Revision: http://reviews.llvm.org/D14729
llvm-svn: 254321
These changes allow libhwloc to be used as the topology discovery/affinity
mechanism for libomp. It is supported on Unices. The code additions:
* Canonicalize KMP_CPU_* interface macros so bitmask operations are
implementation independent and work with both hwloc bitmaps and libomp
bitmaps. So there are new KMP_CPU_ALLOC_* and KMP_CPU_ITERATE() macros and
the like. These are all in kmp.h and appropriately placed.
* Hwloc topology discovery code in kmp_affinity.cpp. This uses the hwloc
interface to create a libomp address2os object which the rest of libomp knows
how to handle already.
* To build, use -DLIBOMP_USE_HWLOC=on and
-DLIBOMP_HWLOC_INSTALL_DIR=/path/to/install/dir [default /usr/local]. If CMake
can't find the library or hwloc.h, then it will tell you and exit.
Differential Revision: http://reviews.llvm.org/D13991
llvm-svn: 254320
Fix ittnotify loop metadata reporting for schedule(runtime) and
chunked schedule set via OMP_SCHEDULE. The bug was that chunk=1
reported always.
llvm-svn: 252952
The patch adds support for ompt_event_task_switch into LLVM/OpenMP. Note that
the patch has also updated the signature of ompt_event_task_switch to
ompt_task_pair_callback_t (rather than the previous ompt_task_switch_callback_t).
Patch by Harald Servat
Differential Revision: http://reviews.llvm.org/D14566
llvm-svn: 252761
1) Add get_ptr_type() method to all wait flag types.
2) Flag in sleep_loc may change type by the time the resume is called from
__kmp_null_resume_wrapper. We use get_ptr_type to obtain the real type
and compare it to the casted object received. If they don't match, we know
the flag has changed (already resumed and replaced by another flag). If they
match, it doesn't hurt to go ahead and resume it.
Differential Revision: http://reviews.llvm.org/D14458
llvm-svn: 252487
1) When the number of threads in a team increases, new threads need to have all
their barrier struct fields initialized. We were missing the parent_bar and
team fields.
2) For non-forkjoin barriers, we now do the __kmp_task_team_setup before the
gather. The setup now sets up the task_team that all the threads will switch
to after the barrier, but it needs to be done before other threads do the
switch.
3) Remove an unneeded assignment of tt_found_tasks in task team free function.
Differential Revision: http://reviews.llvm.org/D14456
llvm-svn: 252486
These changes include:
1) Machine hierarchy now uses the base_num_threads field to indicate the
maximum number of threads the current hierarchy can handle without a resize.
2) In __kmp_get_hierarchy, we need to get depth after any potential resize
is done.
3) Cleanup of hierarchy resize code to support 1 above.
Differential Revision: http://reviews.llvm.org/D14455
llvm-svn: 252475
Jonathan Peyton