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// Copyright 2018 The Abseil Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// https://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include "absl/hash/internal/hash.h"
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namespace absl {
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ABSL_NAMESPACE_BEGIN
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namespace hash_internal {
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Export of internal Abseil changes
--
9fc37c11b9e46287acef00ee06ed9adcba54dd13 by Greg Falcon <gfalcon@google.com>:
Rename absl::hash_internal::HashState to absl::hash_internal::MixingHashState.
Before this change, we had two classes named HashState: absl::HashState, the public API used for type erasure, and absl::hash_internal::HashState, the internal concrete implementation ordinarily used.
The internal class used to be named `CityHashState`, but we renamed it to `HashState` it when we changed underlying hash implementation to wyhash. This inadvertent naming conflict made the code much harder to read, and this change intends to undo that.
PiperOrigin-RevId: 373481959
--
4aec55ffddebd085c239352a2e20721091f719a1 by Greg Falcon <gfalcon@google.com>:
Introduce absl::HashOf(), a convenience wrapper around absl::Hash that calculates hashes from the values of its arguments.
PiperOrigin-RevId: 373461406
--
86b5fd8db50bbc8bd0aa9258523527381fe0445d by Abseil Team <absl-team@google.com>:
Improve speed of BlockingCounter by making its most common path lock free.
With the new implementation, the fast path of BlockingCounter::DecrementCount()
is only a fetch_sub operation. This is most times much more efficient than the
previous implementation (full mutex lock/unlock). As a matter of fact, in most
actual usecases in practice, the waiter thread is already waiting on the
Wait() call when DecrementCount() is called, which makes Mutex::Unlock() take
the slow path as there's a waiter thread that it might need to wake up.
PiperOrigin-RevId: 373394164
--
65c876be5eac0cd32583ff8535ede4109d39cf3f by Martijn Vels <mvels@google.com>:
Move the 'sample copied cord' logic into MaybeTrackCord(),
This changes move the logic for selecting if a cord should remain being sampled from Cord to CordzInfo::MaybeTrackCord, and updates the documentation for the latter method.
PiperOrigin-RevId: 373363168
--
e84410bd0aada293a81dfb82656c952e209e21fb by Martijn Vels <mvels@google.com>:
Add check for the first call to cordz_should_profile() for each thread.
This prevents the first cord of a newly created thread to be always sampled, which is a 'bad' kind of determinism for sampling.
PiperOrigin-RevId: 373229768
--
bf09c589dc099ac8f4af780bf7e609c53c27574c by Samuel Benzaquen <sbenza@google.com>:
Refactor the Flags structure into an enum.
This gives us more control over the representation and allows for easier
merging during parsing.
PiperOrigin-RevId: 373163038
--
b947b0c51083b7b6508284b5d31819596c91729e by Derek Mauro <dmauro@google.com>:
Fixes warnings about shadowed variables
Fixes #956
PiperOrigin-RevId: 373158133
GitOrigin-RevId: 9fc37c11b9e46287acef00ee06ed9adcba54dd13
Change-Id: I91f35699f9bf439d1a870c6493946a310afe088c
4 years ago
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uint64_t MixingHashState::CombineLargeContiguousImpl32(
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uint64_t state, const unsigned char* first, size_t len) {
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while (len >= PiecewiseChunkSize()) {
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state =
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Mix(state, absl::hash_internal::CityHash32(reinterpret_cast<const char*>(first),
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PiecewiseChunkSize()));
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len -= PiecewiseChunkSize();
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first += PiecewiseChunkSize();
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}
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// Handle the remainder.
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return CombineContiguousImpl(state, first, len,
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std::integral_constant<int, 4>{});
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}
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Export of internal Abseil changes
--
9fc37c11b9e46287acef00ee06ed9adcba54dd13 by Greg Falcon <gfalcon@google.com>:
Rename absl::hash_internal::HashState to absl::hash_internal::MixingHashState.
Before this change, we had two classes named HashState: absl::HashState, the public API used for type erasure, and absl::hash_internal::HashState, the internal concrete implementation ordinarily used.
The internal class used to be named `CityHashState`, but we renamed it to `HashState` it when we changed underlying hash implementation to wyhash. This inadvertent naming conflict made the code much harder to read, and this change intends to undo that.
PiperOrigin-RevId: 373481959
--
4aec55ffddebd085c239352a2e20721091f719a1 by Greg Falcon <gfalcon@google.com>:
Introduce absl::HashOf(), a convenience wrapper around absl::Hash that calculates hashes from the values of its arguments.
PiperOrigin-RevId: 373461406
--
86b5fd8db50bbc8bd0aa9258523527381fe0445d by Abseil Team <absl-team@google.com>:
Improve speed of BlockingCounter by making its most common path lock free.
With the new implementation, the fast path of BlockingCounter::DecrementCount()
is only a fetch_sub operation. This is most times much more efficient than the
previous implementation (full mutex lock/unlock). As a matter of fact, in most
actual usecases in practice, the waiter thread is already waiting on the
Wait() call when DecrementCount() is called, which makes Mutex::Unlock() take
the slow path as there's a waiter thread that it might need to wake up.
PiperOrigin-RevId: 373394164
--
65c876be5eac0cd32583ff8535ede4109d39cf3f by Martijn Vels <mvels@google.com>:
Move the 'sample copied cord' logic into MaybeTrackCord(),
This changes move the logic for selecting if a cord should remain being sampled from Cord to CordzInfo::MaybeTrackCord, and updates the documentation for the latter method.
PiperOrigin-RevId: 373363168
--
e84410bd0aada293a81dfb82656c952e209e21fb by Martijn Vels <mvels@google.com>:
Add check for the first call to cordz_should_profile() for each thread.
This prevents the first cord of a newly created thread to be always sampled, which is a 'bad' kind of determinism for sampling.
PiperOrigin-RevId: 373229768
--
bf09c589dc099ac8f4af780bf7e609c53c27574c by Samuel Benzaquen <sbenza@google.com>:
Refactor the Flags structure into an enum.
This gives us more control over the representation and allows for easier
merging during parsing.
PiperOrigin-RevId: 373163038
--
b947b0c51083b7b6508284b5d31819596c91729e by Derek Mauro <dmauro@google.com>:
Fixes warnings about shadowed variables
Fixes #956
PiperOrigin-RevId: 373158133
GitOrigin-RevId: 9fc37c11b9e46287acef00ee06ed9adcba54dd13
Change-Id: I91f35699f9bf439d1a870c6493946a310afe088c
4 years ago
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uint64_t MixingHashState::CombineLargeContiguousImpl64(
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uint64_t state, const unsigned char* first, size_t len) {
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while (len >= PiecewiseChunkSize()) {
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state = Mix(state, Hash64(first, PiecewiseChunkSize()));
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len -= PiecewiseChunkSize();
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first += PiecewiseChunkSize();
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}
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// Handle the remainder.
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return CombineContiguousImpl(state, first, len,
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std::integral_constant<int, 8>{});
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}
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Export of internal Abseil changes
--
9fc37c11b9e46287acef00ee06ed9adcba54dd13 by Greg Falcon <gfalcon@google.com>:
Rename absl::hash_internal::HashState to absl::hash_internal::MixingHashState.
Before this change, we had two classes named HashState: absl::HashState, the public API used for type erasure, and absl::hash_internal::HashState, the internal concrete implementation ordinarily used.
The internal class used to be named `CityHashState`, but we renamed it to `HashState` it when we changed underlying hash implementation to wyhash. This inadvertent naming conflict made the code much harder to read, and this change intends to undo that.
PiperOrigin-RevId: 373481959
--
4aec55ffddebd085c239352a2e20721091f719a1 by Greg Falcon <gfalcon@google.com>:
Introduce absl::HashOf(), a convenience wrapper around absl::Hash that calculates hashes from the values of its arguments.
PiperOrigin-RevId: 373461406
--
86b5fd8db50bbc8bd0aa9258523527381fe0445d by Abseil Team <absl-team@google.com>:
Improve speed of BlockingCounter by making its most common path lock free.
With the new implementation, the fast path of BlockingCounter::DecrementCount()
is only a fetch_sub operation. This is most times much more efficient than the
previous implementation (full mutex lock/unlock). As a matter of fact, in most
actual usecases in practice, the waiter thread is already waiting on the
Wait() call when DecrementCount() is called, which makes Mutex::Unlock() take
the slow path as there's a waiter thread that it might need to wake up.
PiperOrigin-RevId: 373394164
--
65c876be5eac0cd32583ff8535ede4109d39cf3f by Martijn Vels <mvels@google.com>:
Move the 'sample copied cord' logic into MaybeTrackCord(),
This changes move the logic for selecting if a cord should remain being sampled from Cord to CordzInfo::MaybeTrackCord, and updates the documentation for the latter method.
PiperOrigin-RevId: 373363168
--
e84410bd0aada293a81dfb82656c952e209e21fb by Martijn Vels <mvels@google.com>:
Add check for the first call to cordz_should_profile() for each thread.
This prevents the first cord of a newly created thread to be always sampled, which is a 'bad' kind of determinism for sampling.
PiperOrigin-RevId: 373229768
--
bf09c589dc099ac8f4af780bf7e609c53c27574c by Samuel Benzaquen <sbenza@google.com>:
Refactor the Flags structure into an enum.
This gives us more control over the representation and allows for easier
merging during parsing.
PiperOrigin-RevId: 373163038
--
b947b0c51083b7b6508284b5d31819596c91729e by Derek Mauro <dmauro@google.com>:
Fixes warnings about shadowed variables
Fixes #956
PiperOrigin-RevId: 373158133
GitOrigin-RevId: 9fc37c11b9e46287acef00ee06ed9adcba54dd13
Change-Id: I91f35699f9bf439d1a870c6493946a310afe088c
4 years ago
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ABSL_CONST_INIT const void* const MixingHashState::kSeed = &kSeed;
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// The salt array used by Wyhash. This array is NOT the mechanism used to make
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// absl::Hash non-deterministic between program invocations. See `Seed()` for
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// that mechanism.
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//
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// Any random values are fine. These values are just digits from the decimal
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// part of pi.
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// https://en.wikipedia.org/wiki/Nothing-up-my-sleeve_number
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constexpr uint64_t kWyhashSalt[5] = {
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uint64_t{0x243F6A8885A308D3}, uint64_t{0x13198A2E03707344},
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uint64_t{0xA4093822299F31D0}, uint64_t{0x082EFA98EC4E6C89},
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uint64_t{0x452821E638D01377},
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};
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Export of internal Abseil changes
--
9fc37c11b9e46287acef00ee06ed9adcba54dd13 by Greg Falcon <gfalcon@google.com>:
Rename absl::hash_internal::HashState to absl::hash_internal::MixingHashState.
Before this change, we had two classes named HashState: absl::HashState, the public API used for type erasure, and absl::hash_internal::HashState, the internal concrete implementation ordinarily used.
The internal class used to be named `CityHashState`, but we renamed it to `HashState` it when we changed underlying hash implementation to wyhash. This inadvertent naming conflict made the code much harder to read, and this change intends to undo that.
PiperOrigin-RevId: 373481959
--
4aec55ffddebd085c239352a2e20721091f719a1 by Greg Falcon <gfalcon@google.com>:
Introduce absl::HashOf(), a convenience wrapper around absl::Hash that calculates hashes from the values of its arguments.
PiperOrigin-RevId: 373461406
--
86b5fd8db50bbc8bd0aa9258523527381fe0445d by Abseil Team <absl-team@google.com>:
Improve speed of BlockingCounter by making its most common path lock free.
With the new implementation, the fast path of BlockingCounter::DecrementCount()
is only a fetch_sub operation. This is most times much more efficient than the
previous implementation (full mutex lock/unlock). As a matter of fact, in most
actual usecases in practice, the waiter thread is already waiting on the
Wait() call when DecrementCount() is called, which makes Mutex::Unlock() take
the slow path as there's a waiter thread that it might need to wake up.
PiperOrigin-RevId: 373394164
--
65c876be5eac0cd32583ff8535ede4109d39cf3f by Martijn Vels <mvels@google.com>:
Move the 'sample copied cord' logic into MaybeTrackCord(),
This changes move the logic for selecting if a cord should remain being sampled from Cord to CordzInfo::MaybeTrackCord, and updates the documentation for the latter method.
PiperOrigin-RevId: 373363168
--
e84410bd0aada293a81dfb82656c952e209e21fb by Martijn Vels <mvels@google.com>:
Add check for the first call to cordz_should_profile() for each thread.
This prevents the first cord of a newly created thread to be always sampled, which is a 'bad' kind of determinism for sampling.
PiperOrigin-RevId: 373229768
--
bf09c589dc099ac8f4af780bf7e609c53c27574c by Samuel Benzaquen <sbenza@google.com>:
Refactor the Flags structure into an enum.
This gives us more control over the representation and allows for easier
merging during parsing.
PiperOrigin-RevId: 373163038
--
b947b0c51083b7b6508284b5d31819596c91729e by Derek Mauro <dmauro@google.com>:
Fixes warnings about shadowed variables
Fixes #956
PiperOrigin-RevId: 373158133
GitOrigin-RevId: 9fc37c11b9e46287acef00ee06ed9adcba54dd13
Change-Id: I91f35699f9bf439d1a870c6493946a310afe088c
4 years ago
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uint64_t MixingHashState::WyhashImpl(const unsigned char* data, size_t len) {
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return Wyhash(data, len, Seed(), kWyhashSalt);
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}
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} // namespace hash_internal
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ABSL_NAMESPACE_END
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} // namespace absl
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