This patch cleans up the yielding code and makes it optional. An
environment variable, KMP_USE_YIELD, was added. Yielding is still
on by default (KMP_USE_YIELD=1), but can be turned off completely
(KMP_USE_YIELD=0), or turned on only when oversubscription is detected
(KMP_USE_YIELD=2). Note that oversubscription cannot always be detected
by the runtime (for example, when the runtime is initialized and the
process forks, oversubscription cannot be detected currently over
multiple instances of the runtime).
Because yielding can be controlled by user now, the library mode
settings (from KMP_LIBRARY) for throughput and turnaround have been
adjusted by altering blocktime, unless that was also explicitly set.
In the original code, there were a number of places where a double yield
might have been done under oversubscription. This version checks
oversubscription and if that's not going to yield, then it does
the spin check.
Patch by Terry Wilmarth
Differential Revision: https://reviews.llvm.org/D58148
llvm-svn: 355120
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
Add omp_pause_resource and omp_pause_resource_all API and enum, plus stub for
internal implementation. Implemented callable helper function to do local pause,
and added basic functionality for hard and soft pause.
Patch by Terry Wilmarth
Differential Revision: https://reviews.llvm.org/D55078
llvm-svn: 351372
The value returned by __kmp_now_nsec() can overflow 32-bit values causing
incorrect values to be returned. The overflow can end up causing a divide
by zero error because in __kmp_initialize_system_tick(), the value
(__kmp_now_nsec() - nsec) can end up being much larger than the numerator:
1e6 * (delay + (now - goal))
during a pathological timing where the current time calculated is much larger
than nsec. When this happens, the value of __kmp_ticks_per_msec is set to zero
which is then used as the denominator in the KMP_NOW_MSEC() macro leading to
the divide by zero error.
Differential Revision: https://reviews.llvm.org/D55300
llvm-svn: 349090
Switch NetBSD from reading /proc (which is broken) to getloadavg()
(which is already used by Darwin). NetBSD discourages using procfs
in favor of system API calls.
Differential Revision: https://reviews.llvm.org/D55486
llvm-svn: 348885
Summary:
Use the sysctl(3) function to check whether an address is mapped
into the address space.
Reviewers: mgorny, joerg, #openmp
Reviewed By: mgorny
Subscribers: openmp-commits
Tags: #openmp
Differential Revision: https://reviews.llvm.org/D55549
llvm-svn: 348874
Summary: This patch permits OpenMP to build and work (with both gcc and clang) on OpenBSD. It mostly follows what was done for FreeBSD and NetBSD, except OpenBSD does not have pthread_getattr_np support, so it follows OS X in that one instance.
Reviewers: #openmp, krytarowski
Reviewed By: krytarowski
Subscribers: guansong, jfb, emaste, mgorny, krytarowski, #openmp
Tags: #openmp
Differential Revision: https://reviews.llvm.org/D34280
llvm-svn: 348726
Summary:
Additions mostly follow FreeBSD and NetBSD and are not intrusive.
There is similar patch for OpenBSD: https://reviews.llvm.org/D34280
The -lm was being omitted due to -Wl,--as-needed in cmake rule, similar patch is in freebsd-ports/devel/llvm-devel port.
Simple OpenMP programs compile and work as expected:
$ clang-devel ~/omp_hello.c -fopenmp -I/usr/local/llvm-devel/include
$ LD_LIBRARY_PATH=/usr/local/llvm-devel/lib OMP_NUM_THREADS=100 ./a.out
The assertion in LLVMgold.so when -fopenmp was used together with -flto in 20170524 snapshot is no longer triggered on current svn-trunk and works fine as in llvm-4.0 with our local patches.
Reviewers: #openmp, krytarowski
Reviewed By: krytarowski
Subscribers: dexonsmith, jfb, krytarowski, guansong, gregrodgers, emaste, mgorny, mehdi_amini
Differential Revision: https://reviews.llvm.org/D35129
llvm-svn: 348725
1) Remove unnecessary data from list node structure
2) Remove timerPair in favor of pushing/popping explicitTimers.
This way, nested timers will work properly.
3) Fix #pragma omp critical timers
4) Add histogram capability
5) Add KMP_STATS_FILE formatting capability
6) Have time partitioned into serial & parallel by introducing
partitionedTimers::exchange(). This also counts the number of serial regions
in the executable.
7) Fix up the timers around OMP loops so that scheduling overhead and work are
both counted correctly.
8) Fix up the iterations statistics so they count the number of iterations the
thread receives at each loop scheduling event
9) Change timers so there is only one RDTSC read per event change
10) Fix up the outdated comments for the timers
Differential Revision: https://reviews.llvm.org/D49699
llvm-svn: 338276
These are preliminary changes that attempt to use C++11 Atomics in the runtime.
We are expecting better portability with this change across architectures/OSes.
Here is the summary of the changes.
Most variables that need synchronization operation were converted to generic
atomic variables (std::atomic<T>). Variables that are updated with combined CAS
are packed into a single atomic variable, and partial read/write is done
through unpacking/packing
Patch by Hansang Bae
Differential Revision: https://reviews.llvm.org/D47903
llvm-svn: 336563
This change removes the unnecessary lock operation on __kmp_initz_lock inside
the __kmp_atfork_child() function for Linux; the lock variable is initialized
in the same function later.
Patch by Hansang Bae
Differential Revision: https://reviews.llvm.org/D44949
llvm-svn: 328900
This change improves stability of the runtime when the application forks child
processes. Acquiring/releasing __kmp_initz_lock and __kmp_forkjoin_lock in the
atfork handlers insures that the actual fork does not occur while those two
locks are held, and __kmp_itt_reset() reverts the itt's global state to the
initial state which also initializes the mutex stored in the global state.
Some missing initialization code was also inserted in the child's atfork handler.
Patch by Hansang Bae
Differential Revision: https://reviews.llvm.org/D41462
llvm-svn: 322202
1) Get rid of xaliasify, xexpand and xversionify for KMP_EXPAND_NAME and
KMP_VERSION_SYMBOL. KMP_VERSION_SYMBOL is a combination of xaliasify and
xversionify.
2) Put all attribute and __declspec definitions in kmp_os.h
Differential Revision: https://reviews.llvm.org/D39516
llvm-svn: 317636
The code is tested to work with latest clang, GNU and Intel compiler. The implementation
is optimized for low overhead when no tool is attached shifting the cost to execution with
tool attached.
This patch does not implement OMPT for libomptarget.
Patch by Simon Convent and Joachim Protze
Differential Revision: https://reviews.llvm.org/D38185
llvm-svn: 317085
Removes semicolons after if {} blocks, function definitions, etc.
I was able to apply the large OMPT patch cleanly on top of this one
with no conflicts.
llvm-svn: 314340
Minor code cleanup of Klocwork issues. Fatal messages are given no return
attribute. Define and use KMP_NORETURN to work for multiple C++ versions.
Patch by Terry Wilmarth
Differential Revision: https://reviews.llvm.org/D37275
llvm-svn: 312538
Cleanup code to remove BUILD_TV and unused code bracketed by it.
Patch by Terry Wilmarth
Differential Revision: https://reviews.llvm.org/D36011
llvm-svn: 311114
Changes are: got all atomics to accept volatile pointers that allowed
to simplify many type conversions. Windows specific code fixed correspondingly.
Differential Revision: https://reviews.llvm.org/D35417
llvm-svn: 308164
Changes are: replaced C-style casts with cons_cast and reinterpret_cast;
type of several counters changed to signed; type of parameters of 32-bit and
64-bit AND and OR intrinsics changes to unsigned; changed files formatted
using clang-format version 3.8.1.
Differential Revision: https://reviews.llvm.org/D34759
llvm-svn: 307020
Reset affinity to none (false for proc-bind-var) so that threads in the child
processes are not bound tightly, unless the user explicitly sets this in
KMP_AFFINITY/OMP_PROC_BIND, in child processes. This can improve
performance for scripting languages which fork for parallelism like Python's
multiprocessing module.
Differential Revision: https://reviews.llvm.org/D34154
llvm-svn: 305513
If OpenMP is initialized before fork()-ing occurs and affinity is set to
something like compact, then the master thread will be pinned to a single HW
thread/core after initialization. If the master (or any other thread) then
forks N processes, all N processes will then be pinned to that same single HW
thread/core. To reset the affinity for the new child process, the atfork
handler for the child process can call kmp_set_thread_affinity_mask_initial()
to reset its affinity to the initial affinity of the application before it
re-initializes libomp. The parent process will not be affected and still
keeps its affinity setting.
Differential Revision: https://reviews.llvm.org/D34118
llvm-svn: 305306
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
This change slightly improves performance of KMP_YIELD_NOW() macro, by using
_rdtsc() intrinsic function if possible.
Patch by Hansang Bae
Differential Revision: https://reviews.llvm.org/D31008
llvm-svn: 298314
This section of code (__kmp_test_then_* functions) is guarded by
(KMP_ARCH_X86 || KMP_ARCH_X86_64) so it does not make sense to have other
architecture guards inside this section. Non-x86 architectures always
use intrinsics (__sync_*)
llvm-svn: 296525
This change allows the runtime to turn __kmp_yield() on/off repeatedly on Linux.
This feature was removed when disabling monitor thread, but there are
applications that perform better with this feature on.
Patch by Hansang Bae
Differential Revision: https://reviews.llvm.org/D29227
llvm-svn: 295203
