Standalone build for OpenMP runtime using GCC is giving -Wcomment
warnings where a backslash newline is encountered in the // style
comment. This switches the // style for /* style to silence the
warnings.
This patch includes a few changes to improve task allocation
performance slightly. These changes are enough to restore performance
drop observed after introducing hidden helper.
Differential Revision: https://reviews.llvm.org/D105715
There is no guarantee that the space allocated in `libname`
is enough to accomodate the whole `dl_info.dli_fname`,
because it could e.g. have an suffix - `.5`,
and that highlights another problem - what it should do about suffxies,
and should it do anything to resolve the symlinks before changing the filename?
```
$ LD_LIBRARY_PATH="$LD_LIBRARY_PATH:/usr/local/lib" ./src/utilities/rstest/rstest -c /tmp/f49137920.NEF
dl_info.dli_fname "/usr/local/lib/libomp.so.5"
strlen(dl_info.dli_fname) 26
lib_path_length 14
lib_path_length + 12 26
=================================================================
==30949==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x60300000002a at pc 0x000000548648 bp 0x7ffdfa0aa780 sp 0x7ffdfa0a9f40
WRITE of size 27 at 0x60300000002a thread T0
#0 0x548647 in strcpy (/home/lebedevri/rawspeed/build-Clang-SANITIZE/src/utilities/rstest/rstest+0x548647)
#1 0x7fb9e3e3d234 in ompd_init() /repositories/llvm-project/openmp/runtime/src/ompd-specific.cpp:102:5
#2 0x7fb9e3dcb446 in __kmp_do_serial_initialize() /repositories/llvm-project/openmp/runtime/src/kmp_runtime.cpp:6742:3
#3 0x7fb9e3dcb40b in __kmp_get_global_thread_id_reg /repositories/llvm-project/openmp/runtime/src/kmp_runtime.cpp:251:7
#4 0x59e035 in main /home/lebedevri/rawspeed/build-Clang-SANITIZE/../src/utilities/rstest/rstest.cpp:491
#5 0x7fb9e3762d09 in __libc_start_main csu/../csu/libc-start.c:308:16
#6 0x4df449 in _start (/home/lebedevri/rawspeed/build-Clang-SANITIZE/src/utilities/rstest/rstest+0x4df449)
0x60300000002a is located 0 bytes to the right of 26-byte region [0x603000000010,0x60300000002a)
allocated by thread T0 here:
#0 0x55cc5d in malloc (/home/lebedevri/rawspeed/build-Clang-SANITIZE/src/utilities/rstest/rstest+0x55cc5d)
#1 0x7fb9e3e3d224 in ompd_init() /repositories/llvm-project/openmp/runtime/src/ompd-specific.cpp:101:17
#2 0x7fb9e3762d09 in __libc_start_main csu/../csu/libc-start.c:308:16
SUMMARY: AddressSanitizer: heap-buffer-overflow (/home/lebedevri/rawspeed/build-Clang-SANITIZE/src/utilities/rstest/rstest+0x548647) in strcpy
Shadow bytes around the buggy address:
0x0c067fff7fb0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c067fff7fc0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c067fff7fd0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c067fff7fe0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c067fff7ff0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0c067fff8000: fa fa 00 00 00[02]fa fa fa fa fa fa fa fa fa fa
0x0c067fff8010: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c067fff8020: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c067fff8030: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c067fff8040: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c067fff8050: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
Shadow byte legend (one shadow byte represents 8 application bytes):
Addressable: 00
Partially addressable: 01 02 03 04 05 06 07
Heap left redzone: fa
Freed heap region: fd
Stack left redzone: f1
Stack mid redzone: f2
Stack right redzone: f3
Stack after return: f5
Stack use after scope: f8
Global redzone: f9
Global init order: f6
Poisoned by user: f7
Container overflow: fc
Array cookie: ac
Intra object redzone: bb
ASan internal: fe
Left alloca redzone: ca
Right alloca redzone: cb
==30949==ABORTING
Aborted
```
The annotations in libomp were never built by default. The annotations are
also superseded by the annotations which the OMPT tool libarcher.so provides.
With respect to libarcher, libomp behaves as if libarcher would be the last
element of OMP_TOOL_LIBARARIES. I.e., if no other OMPT tool gets active,
libarcher will check if an OpenMP application is built with TSan.
Since libarcher gets loaded by default, enabling LIBOMP_TSAN_SUPPORT would
result in redundant annotations for TSan, which slightly differ in details
and coverage (e.g. task dependencies are not handled well by the annotations
in libomp).
This patch removes all TSan annotations from the OpenMP runtime code.
Differential Revision: https://reviews.llvm.org/D103767
This patch includes the following changes to address a few issues when
using hidden helper task.
- Assertion is triggered when there are inadvertent calls to hidden
helper functions on non-Linux OS
- Added deinit code in __kmp_internal_end_library function to fix random
shutdown crashes
- Moved task data access into the lock-guarded region in __kmp_push_task
Differential Revision: https://reviews.llvm.org/D105308
This reverts commit eab1fd389b.
This commit fixed a problem with 25073a4ecf (D103121) which is the one
we actually need to revert to unblock non-X86 builds of OpenMP. Can be
reapplied, or merged into, D103121 as it goes in again.
Normalized bounds of chunk of iterations to steal from are inclusive,
so upper bound should not be decremented in expression to check.
Problem was in attempt to steal iterations 0:0, that caused assertion after
wrong decrement. Reported in comment to https://reviews.llvm.org/D103648.
Differential Revision: https://reviews.llvm.org/D104880
Restructured dynamic loop dispatcher code.
Fixed use of dispatch buffers for nonmonotonic dynamic (static_steal) schedule:
- eliminated possibility of stealing iterations of the wrong loop when victim
thread changed its buffer to work on another loop;
- fixed race when victim thread changed its buffer to work in nested parallel;
- eliminated "static" property of the schedule, that is now a single thread can
execute whole loop.
Differential Revision: https://reviews.llvm.org/D103648
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
Refactored code of dependence processing and added new inoutset dependence type.
Compiler can set dependence flag to 0x8 when call __kmpc_omp_task_with_deps.
All dependence flags library gets so far and corresponding dependence types:
1 - IN, 2 - OUT, 3 - INOUT, 4 - MUTEXINOUTSET, 8 - INOUTSET.
Differential Revision: https://reviews.llvm.org/D97085
Several variables were left unused as a result of different patches removing
their use.
Two variables have some use:
`poll_count` is used by the KMP_BLOCKING macro only under certain conditions.
Adding (void) to tell the compiler to ignore the unused variable.
`padding` is a dummy stack allocation with no intent to be used. Also adding
(void) to make the compiler ignore the unused variable.
Differential Revision: https://reviews.llvm.org/D104303
* Add GOMP versioned pause functions
* Add GOMP versioned affinity format functions
To do the affinity format functions, only attach versioned symbols
to the APPEND Fortran entries (e.g., omp_set_affinity_format_) since
GOMP only exports two symbols (one for Fortran, one for C). Our
affinity format functions have three symbols.
e.g., with omp_set_affinity_format:
1) omp_set_affinity_format (Fortran interface)
2) omp_set_affinity_format_ (Fortran interface)
3) ompc_set_affinity_format (C interface)
Have the GOMP version of the C symbol alias the ompc_* 3) version
instead of the Fortran unappended version 1).
Differential Revision: https://reviews.llvm.org/D103647
Remove strange checks for syscall() arguments where mask is NULL.
Valgrind reports these as error usages for the syscall.
Instead, just check if CACHE_LINE bytes is long enough. If not, then
search for the size. Also, by limiting the first size detection
attempt to CACHE_LINE bytes, instead of 1MB, we don't use more than one
cache line for the mask size. Before this patch, sometimes the returned
mask size was 640 bytes (10 cache lines) because the initial call to
getaffinity() was limited only by the internal kernel mask size
which can be very large.
Differential Revision: https://reviews.llvm.org/D103637
Lazily set affinity for root threads. Previously, the root thread
executing middle initialization would attempt to assign affinity
to other existing root threads. This was not working properly as the
set_system_affinity() function wasn't setting the affinity for the
target thread. Instead, the middle init thread was resetting the
its own affinity using the target thread's affinity mask.
Differential Revision: https://reviews.llvm.org/D103625
This is the first of seven patches that implements OMPD, a debugging interface to support debugging of OpenMP programs.
It contains support code required in "openmp/runtime" for OMPD implementation.
Reviewed By: @hbae
Differential Revision: https://reviews.llvm.org/D100181
Refactored code of dependence processing and added new inoutset dependence type.
Compiler can set dependence flag to 0x8 when call __kmpc_omp_task_with_deps.
Size of type of the dependence flag changed from 1 to 4 bytes in clang.
All dependence flags library gets so far and corresponding dependence types:
1 - IN, 2 - OUT, 3 - INOUT, 4 - MUTEXINOUTSET, 8 - INOUTSET.
Differential Revision: https://reviews.llvm.org/D97085
The ident_t * argument in __kmp_get_monotonicity was being used without
a customary NULL check, causing the function to crash in a Debug build.
Release builds were not affected thanks to dead store elimination.
Nesting mode is a new experimental feature in the OpenMP
runtime. It allows a user to set up nesting for an application in a
way that corresponds to the hardware topology levels on the machine an
application is being run on. For example, if a machine has 2 sockets,
each with 12 cores, then use of nesting mode could set up an outer
level of nesting that uses 2 threads per parallel region, and an inner
level of nesting that uses 12 threads per parallel region.
Nesting mode is controlled with the KMP_NESTING_MODE environment
variable as follows:
1) KMP_NESTING_MODE = 0: Nesting mode is off (default); max-active-levels-var
is set to 1 (the default -- nesting is off, nested parallel regions
are serialized).
2) KMP_NESTING_MODE = 1: Nesting mode is on, and a number of threads
will be assigned for each level discovered in the machine topology;
max-active-levels-var is set to the number of levels discovered.
3) KMP_NESTING_MODE = n, n>1: [Note: this option is experimental and may change
or be removed in the future.] Nesting mode is on, and a number of
threads will be assigned for each topology level discovered on the
machine, up to k<=n levels (since there may be fewer than n levels
discovered in the topology), and beyond the kth level, nested parallel
regions will be serialized; NOTE: max-active-levels-var is 1 (the default --
nesting is off, and nested parallel regions are serialized until the
user changes max-active-levels-var.
If the user sets OMP_NUM_THREADS or OMP_MAX_ACTIVE_LEVELS, they will
override KMP_NESTING_MODE settings for the associated environment
variables. The detected topology may be limited by an affinity mask
setting on the initial thread, or if the user sets KMP_HW_SUBSET. See
also: KMP_HOT_TEAMS_MAX_LEVEL for controlling use of hot teams for
nested parallel regions. Note that this feature only sets numbers of
threads used at nesting levels. The user should make use of
OMP_PLACES and OMP_PROC_BIND or KMP_AFFINITY for affinitizing those
threads, if desired.
Differential Revision: https://reviews.llvm.org/D102188
When on KNL and L2 or Tile layer is detected, manually add
the corresponding layer which is equivalent.
Differential Revision: https://reviews.llvm.org/D102865
Warnings on deprecated api cannot be suppressed if the library is not initialized.
With this change it is possible to set KMP_WARNINGS=false to suppress the warnings.
Differential Revision: https://reviews.llvm.org/D102676
Bug 49356 (https://bugs.llvm.org/show_bug.cgi?id=49356) reports crash in
the test case `tasking/bug_taskwait_detach.cpp`, which is caused by the wrong
function declaration. `gtid` in `__kmpc_omp_task` should be `kmp_int32`.
Reviewed By: AndreyChurbanov
Differential Revision: https://reviews.llvm.org/D102584
This is the first in a series of changes to the OpenMP runtime
that have been done internally by Microsoft. This patch makes
the necessary changes to enable libomp.dll to build with
the MSVC compiler targeting ARM64.
Differential Revision: https://reviews.llvm.org/D101173
When KMP_AFFINITY is set, each worker thread's gtid value is used as an
index into the place list to determine the thread's placement. With hidden
helpers enabled, this gtid value is shifted down leading to unexpected
shifted thread placement. This patch restores the previous behavior by
adjusting the mask index to take the number of hidden helper threads
into account.
Hidden helper threads are given the full initial mask and do not
participate in any of the other affinity mechanisms (place partitioning,
balanced affinity). Their affinity is only printed for debug builds.
Differential Revision: https://reviews.llvm.org/D101882
This patch does the following:
1) Introduce kmp_topology_t as the runtime-friendly structure (the
corresponding global variable is __kmp_topology) to determine the
exact machine topology which can vary widely among current and future
architectures. The current design is not easy to expand beyond the assumed
three layer topology: sockets, cores, and threads so a rework capable of
using the existing KMP_AFFINITY mechanisms is required.
This new topology structure has:
* The depth and types of the topology
* Ratio count for each consecutive level (e.g., number of cores per
socket, number of threads per core)
* Absolute count for each level (e.g., 2 sockets, 16 cores, 32 threads)
* Equivalent topology layer map (e.g., Numa domain is equivalent to
socket, L1/L2 cache equivalent to core)
* Whether it is uniform or not
The hardware threads are represented with the kmp_hw_thread_t
structure. This structure contains the ids (e.g., socket 0, core 1,
thread 0) and other information grabbed from the previous Address
structure. The kmp_topology_t structure contains an array of these.
2) Generalize the KMP_HW_SUBSET envirable for the new
kmp_topology_t structure. The algorithm doesn't assume any order with
tiles,numa domains,sockets,cores,threads. Instead it just parses the
envirable, makes sure it is consistent with the detected topology
(including taking into account equivalent layers) and then trims away
the unneeded subset of hardware threads. To enable this, a new
kmp_hw_subset_t structure is introduced which contains a vector of
items (hardware type, number user wants, offset). Any keyword within
__kmp_hw_get_keyword() can be used as a name and can be shortened as
well. e.g.,
KMP_HW_SUBSET=1s,2numa,4tile,2c,3t can be used on the KNL SNC-4 machine.
3) Simplify topology detection functions so they only do the singular
task of detecting the machine's topology. Printing, and all
canonicalizing functionality is now done afterwards. So many lines of
duplicated code are eliminated.
4) Add new ll_caches and numa_domains to OMP_PLACES, and
consequently, KMP_AFFINITY's granularity setting. All the names within
__kmp_hw_get_keyword() are available for use in OMP_PLACES or
KMP_AFFINITY's granularity setting.
5) Simplify and future-proof code where explicit lists of allowed
affinity settings keywords inside if() conditions.
6) Add x86 CPUID leaf 4 cache detection to existing x2apic id method
so equivalent caches could be detected (in particular for the ll_caches
place).
Differential Revision: https://reviews.llvm.org/D100997
Getting my feet wet here as a new committer.
Correct misspelling in check-depends.pl.
Reviewed By: vitalybuka
Differential Revision: https://reviews.llvm.org/D101552
Implement the remaining GOMP_* functions to support task reductions
in taskgroup, parallel, loop, and taskloop constructs. The unused mem
argument to many of the work-sharing constructs has to do with the
scan() directive/ inscan() modifier. If mem is set, each function
will call KMP_FATAL() and tell the user scan/inscan is unsupported. The
GOMP reduction implementation is kept separate from our implementation
because of how GOMP presents reduction data and computes the reductions.
GOMP expects the privatized copies to be present even after a #pragma
omp parallel reduction(task:...) region has ended so the data is stored
inside GOMP's uintptr_t* data pseudo-structure. This style is tightly
coupled with GCC compiler codegen. There also isn't any init(),
combiner(), fini() functions in GOMP's codegen so the two
implementations were to disparate to try to wrap GOMP's around our own.
Differential Revision: https://reviews.llvm.org/D98806
Current atfork() handler for child processes does not reset
the affinity masks array which prevents users from setting their own
affinity in child processes.
Differential Revision: https://reviews.llvm.org/D99218
omp_is_initial_device() is marked as a built-in function in the current
compiler, and user code guarded by this call may be optimized away,
resulting in undesired behavior in some cases. This patch provides a
possible fix for such cases by defining the routine as a variant
function and removing it from builtin list.
Differential Revision: https://reviews.llvm.org/D99447
The second argument to the strnlen_s(str, size) function should be
sizeof(str) when str is a true array of characters with known size
(instead of just a char*). Use type traits to determine if first
parameter is a character array and use the correct size based on that
trait.
Differential Revision: https://reviews.llvm.org/D98209
-- Added or moved checks to appropriate places.
-- Removed ineffective null check where the pointer is already being
dereferenced around the code.
-- Initialized variables that can be used without definitions.
-- Added call to dlclose/FreeLibrary in OMPT tool activation.
-- Added a new build compiler definition.
Differential Revision: https://reviews.llvm.org/D98584
It is reported that after enabling hidden helper thread, the program
can hit the assertion `new_gtid < __kmp_threads_capacity` sometimes. The root
cause is explained as follows. Let's say the default `__kmp_threads_capacity` is
`N`. If hidden helper thread is enabled, `__kmp_threads_capacity` will be offset
to `N+8` by default. If the number of threads we need exceeds `N+8`, e.g. via
`num_threads` clause, we need to expand `__kmp_threads`. In
`__kmp_expand_threads`, the expansion starts from `__kmp_threads_capacity`, and
repeatedly doubling it until the new capacity meets the requirement. Let's
assume the new requirement is `Y`. If `Y` happens to meet the constraint
`(N+8)*2^X=Y` where `X` is the number of iterations, the new capacity is not
enough because we have 8 slots for hidden helper threads.
Here is an example.
```
#include <vector>
int main(int argc, char *argv[]) {
constexpr const size_t N = 1344;
std::vector<int> data(N);
#pragma omp parallel for
for (unsigned i = 0; i < N; ++i) {
data[i] = i;
}
#pragma omp parallel for num_threads(N)
for (unsigned i = 0; i < N; ++i) {
data[i] += i;
}
return 0;
}
```
My CPU is 20C40T, then `__kmp_threads_capacity` is 160. After offset,
`__kmp_threads_capacity` becomes 168. `1344 = (160+8)*2^3`, then the assertions
hit.
Reviewed By: protze.joachim
Differential Revision: https://reviews.llvm.org/D98838
For clang this change is NFC cleanup, because clang
never calls atomic functions from runtime library.
Basically, pause is good in spin-loops waiting for something.
Atomic CAS loops do not wait for anything,
each CAS failure means some other thread progressed.
Performance experiments show that the pause only causes unnecessary slowdown
on CPUs with slow pause instruction, no difference on CPUs with fast pause
instruction, removal of the pause gives lesser binary size which is good.
Differential Revision: https://reviews.llvm.org/D97079
