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author | 2018-12-04 11:01:12 -0800 | |
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committer | 2018-12-04 16:27:57 -0500 | |
commit | 44b0fafc62d9b8f192e8180cbe9c4b806b339d57 (patch) | |
tree | 4ada26427deee54333ac271a26c5fe363ba33cc7 /absl/base/internal | |
parent | 926bfeb9fff223429c12224b7514243886323e8d (diff) |
Export of internal Abseil changes.
--
cd076f55c1fa600131f6dda392533dfe61679fc0 by Abseil Team <absl-team@google.com>:
Internal change
PiperOrigin-RevId: 224008762
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e05f62b01286d51044ff86ec6ef565749b9faf82 by Abseil Team <absl-team@google.com>:
Create a pow10() test helper function to compute guaranteed-precise double values of 10^x. Not all standard libraries ship bit-accurate pow() functions, causing tests to fail that rely on expected values generated by it.
PiperOrigin-RevId: 223883762
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fd88e5e3f7ab80f7f5df9fd1488cd58b4573be69 by Abseil Team <absl-team@google.com>:
Remove some absl:: qualifications to work around inline namespace bugs on MSVC 2015.
PiperOrigin-RevId: 223869642
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6276cfff969d596edd36a2bbaba65ee045808903 by Abseil Team <absl-team@google.com>:
Update absl/memory/CMakeLists.txt to use new functions
i.e. absl_cc_(library|test)
PiperOrigin-RevId: 223854224
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359de9afc7a34c975fd3e0cbc52afd96637d97bd by Chris Kennelly <ckennelly@google.com>:
Mark spinlock_benchmark_common as alwayslink = 1.
PiperOrigin-RevId: 223844536
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450cd8cbe2789a6d54ed1eb87170259bb334f8b9 by Abseil Team <absl-team@google.com>:
Support .* (pointer-to-member dereference) expressions in demangle.cc.
PiperOrigin-RevId: 223826797
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772ca92179c3634f3e31a80bbc272ed8022e3572 by Abseil Team <absl-team@google.com>:
Fix misspellings in absl::variant comments and replace a ' with a `.
PiperOrigin-RevId: 223807911
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35dcdc2fbf299d195658aac101887f6dcad1de2f by Abseil Team <absl-team@google.com>:
Bug fix in CMakeLists.txt file (SRCS --> HDRS).
The compressed_tuple header-only library is being defined
with the SRCS parameter instead of the HDRS parameter and
this has been observed to cause some builds on some platforms
to attempt to create a static library from it which fails
since there are no .cc sources.
PiperOrigin-RevId: 223805367
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4a57a3d2045bb137c0c97958e45ce425190b8d3e by Chris Kennelly <ckennelly@google.com>:
Add test that absl::make_unique value initializes memory.
PiperOrigin-RevId: 223801819
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dfe8289d7f4dcc6bb568a26aaf192a89e896bdfd by Chris Kennelly <ckennelly@google.com>:
SpinLock: Use exchange to avoid missing wakeups.
The default fast path for SpinLock::Unlock does not use an atomic. If the
SpinLock becomes contended while we are unlocking between lockword_.load and
lockword_.store, we will fail to wake up the new waiter. This can cause
unexpected latency spikes.
PiperOrigin-RevId: 223800369
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9b9d35df786482f0016f77dd31691eff81503d23 by Abseil Team <absl-team@google.com>:
Update absl/hash/CMakeLists.txt to use new functions
i.e. absl_cc_(library|test)
PiperOrigin-RevId: 223755819
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c2014e2704b87e7cdce2d2a0287c7e2397752296 by Abseil Team <absl-team@google.com>:
Update absl/debugging/CMakeLists.txt to use new functions
i.e. absl_cc_(library|test)
PiperOrigin-RevId: 223751986
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d83a4e09126400e3fd80645cb03ee558f532271e by Derek Mauro <dmauro@google.com>:
Cleanup synchronization benchmarks.
PiperOrigin-RevId: 223589416
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fad140b473586531b5b12843f942ec27dfcf5e93 by CJ Johnson <johnsoncj@google.com>:
Makes unifies the order of forward_iterator and input_iterator overloads
PiperOrigin-RevId: 223580660
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6cd7c96faa7cc5f79f574e35a1b13837ef187d05 by Abseil Team <absl-team@google.com>:
Internal Change.
PiperOrigin-RevId: 223561629
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bd2e545356b0f548af0e3c14bb2f7f0e712e49d0 by Shaindel Schwartz <shaindel@google.com>:
Remove misleading comments. try_emplace() does not exist for the hash_set containers.
PiperOrigin-RevId: 223543089
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0cd380a53b587eb7aacc4003a4a3bbb6c78d7c10 by Derek Mauro <dmauro@google.com>:
Internal change
PiperOrigin-RevId: 223512551
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7156dfee599cb72e9adddfe0e6ae07a95ddf10bb by Greg Miller <jgm@google.com>:
Fixes UB that would result from constructing, multiplying, or dividing a
Duration with a double "NaN" value. This CL changes the absl::Duration
*implementation* to return an InfiniteDuration value that has the same sign as
the given NaN.
PiperOrigin-RevId: 223407499
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196b7d18609958267951882baf7f9429e49bcafa by CJ Johnson <johnsoncj@google.com>:
Addresses NVCC+MSVC compilation bug where `inlined_capacity()` was not considered valid in constexpr
PiperOrigin-RevId: 223397718
GitOrigin-RevId: cd076f55c1fa600131f6dda392533dfe61679fc0
Change-Id: I5423ca6470f661a7c6f73aa8fee49990446f157f
Diffstat (limited to 'absl/base/internal')
-rw-r--r-- | absl/base/internal/spinlock.h | 4 | ||||
-rw-r--r-- | absl/base/internal/spinlock_benchmark.cc | 52 |
2 files changed, 54 insertions, 2 deletions
diff --git a/absl/base/internal/spinlock.h b/absl/base/internal/spinlock.h index dcce0109..eb3eec9c 100644 --- a/absl/base/internal/spinlock.h +++ b/absl/base/internal/spinlock.h @@ -101,8 +101,8 @@ class LOCKABLE SpinLock { inline void Unlock() UNLOCK_FUNCTION() { ABSL_TSAN_MUTEX_PRE_UNLOCK(this, 0); uint32_t lock_value = lockword_.load(std::memory_order_relaxed); - lockword_.store(lock_value & kSpinLockCooperative, - std::memory_order_release); + lock_value = lockword_.exchange(lock_value & kSpinLockCooperative, + std::memory_order_release); if ((lock_value & kSpinLockDisabledScheduling) != 0) { base_internal::SchedulingGuard::EnableRescheduling(true); diff --git a/absl/base/internal/spinlock_benchmark.cc b/absl/base/internal/spinlock_benchmark.cc new file mode 100644 index 00000000..907d3e27 --- /dev/null +++ b/absl/base/internal/spinlock_benchmark.cc @@ -0,0 +1,52 @@ +// Copyright 2018 The Abseil Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +// See also //absl/synchronization:mutex_benchmark for a comparison of SpinLock +// and Mutex performance under varying levels of contention. + +#include "absl/base/internal/raw_logging.h" +#include "absl/base/internal/scheduling_mode.h" +#include "absl/base/internal/spinlock.h" +#include "absl/synchronization/internal/create_thread_identity.h" +#include "benchmark/benchmark.h" + +namespace { + +template <absl::base_internal::SchedulingMode scheduling_mode> +static void BM_SpinLock(benchmark::State& state) { + // Ensure a ThreadIdentity is installed. + ABSL_INTERNAL_CHECK( + absl::synchronization_internal::GetOrCreateCurrentThreadIdentity() != + nullptr, + "GetOrCreateCurrentThreadIdentity() failed"); + + static auto* spinlock = new absl::base_internal::SpinLock(scheduling_mode); + for (auto _ : state) { + absl::base_internal::SpinLockHolder holder(spinlock); + } +} + +BENCHMARK_TEMPLATE(BM_SpinLock, + absl::base_internal::SCHEDULE_KERNEL_ONLY) + ->UseRealTime() + ->Threads(1) + ->ThreadPerCpu(); + +BENCHMARK_TEMPLATE(BM_SpinLock, + absl::base_internal::SCHEDULE_COOPERATIVE_AND_KERNEL) + ->UseRealTime() + ->Threads(1) + ->ThreadPerCpu(); + +} // namespace |