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authorGravatar Abseil Team <absl-team@google.com>2020-09-01 09:39:43 -0700
committerGravatar Mark Barolak <mbar@google.com>2020-09-01 15:41:52 -0400
commit0e9921b75a0fdd639a504ec8443fc1fe801becd7 (patch)
tree7e1cc238c43f7b31e7a5f0bcb3c8536ee29d55a6 /absl/container/internal/hashtablez_sampler.h
parenta4cbb5f698c42845aab6a6d6318290205e6c5baf (diff)
Export of internal Abseil changes
-- 23500704dd7c2642fad49f88c07ce41ebaab12e4 by Abseil Team <absl-team@google.com>: Change fetch_add() to store(1 + load()) As there is only one concurrent writer to the Info struct, we can avoid using the more expensive fetch_add() function. PiperOrigin-RevId: 329523785 -- 79e5018dba2e117ad89b76367165a604b3f24045 by Abseil Team <absl-team@google.com>: Record rehash count in hashtablez This will help identify which containers could benefit from a reserve call. PiperOrigin-RevId: 329510552 -- e327e54b805d67556f934fa7f7dc2d4e72fa066a by Abseil Team <absl-team@google.com>: Fix -Wsign-compare issues. These lines could theoretically have overflowed in cases of very large stack traces etc. Very unlikely, but this was causing warnings when built with -Wsign-compare, which we intend to enable with Chromium. In none of these three cases is it trivial to switch to a range-based for loop. PiperOrigin-RevId: 329415195 -- 08aca2fc75e8b3ad1201849987b64148fe48f283 by Xiaoyi Zhang <zhangxy@google.com>: Release absl::StatusOr. PiperOrigin-RevId: 329353348 -- bf4d2a7f8b089e2adf14d32b0e39de0a981005c3 by Xiaoyi Zhang <zhangxy@google.com>: Internal change PiperOrigin-RevId: 329337031 -- 42fa7d2fb993bbfc344954227cf1eeb801eca065 by Abseil Team <absl-team@google.com>: Internal change PiperOrigin-RevId: 329099807 GitOrigin-RevId: 23500704dd7c2642fad49f88c07ce41ebaab12e4 Change-Id: I6713e4ca3bb0ab2ced5e487827ae036ab8ac61f1
Diffstat (limited to 'absl/container/internal/hashtablez_sampler.h')
-rw-r--r--absl/container/internal/hashtablez_sampler.h15
1 files changed, 13 insertions, 2 deletions
diff --git a/absl/container/internal/hashtablez_sampler.h b/absl/container/internal/hashtablez_sampler.h
index e140ee00..b2a30c9a 100644
--- a/absl/container/internal/hashtablez_sampler.h
+++ b/absl/container/internal/hashtablez_sampler.h
@@ -73,6 +73,7 @@ struct HashtablezInfo {
std::atomic<size_t> capacity;
std::atomic<size_t> size;
std::atomic<size_t> num_erases;
+ std::atomic<size_t> num_rehashes;
std::atomic<size_t> max_probe_length;
std::atomic<size_t> total_probe_length;
std::atomic<size_t> hashes_bitwise_or;
@@ -105,6 +106,11 @@ inline void RecordRehashSlow(HashtablezInfo* info, size_t total_probe_length) {
#endif
info->total_probe_length.store(total_probe_length, std::memory_order_relaxed);
info->num_erases.store(0, std::memory_order_relaxed);
+ // There is only one concurrent writer, so `load` then `store` is sufficient
+ // instead of using `fetch_add`.
+ info->num_rehashes.store(
+ 1 + info->num_rehashes.load(std::memory_order_relaxed),
+ std::memory_order_relaxed);
}
inline void RecordStorageChangedSlow(HashtablezInfo* info, size_t size,
@@ -113,7 +119,8 @@ inline void RecordStorageChangedSlow(HashtablezInfo* info, size_t size,
info->capacity.store(capacity, std::memory_order_relaxed);
if (size == 0) {
// This is a clear, reset the total/num_erases too.
- RecordRehashSlow(info, 0);
+ info->total_probe_length.store(0, std::memory_order_relaxed);
+ info->num_erases.store(0, std::memory_order_relaxed);
}
}
@@ -122,7 +129,11 @@ void RecordInsertSlow(HashtablezInfo* info, size_t hash,
inline void RecordEraseSlow(HashtablezInfo* info) {
info->size.fetch_sub(1, std::memory_order_relaxed);
- info->num_erases.fetch_add(1, std::memory_order_relaxed);
+ // There is only one concurrent writer, so `load` then `store` is sufficient
+ // instead of using `fetch_add`.
+ info->num_erases.store(
+ 1 + info->num_erases.load(std::memory_order_relaxed),
+ std::memory_order_relaxed);
}
HashtablezInfo* SampleSlow(int64_t* next_sample);