strings/internal/cordz_statistics.h

0001 // Copyright 2019 The Abseil Authors.
0002 //
0003 // Licensed under the Apache License, Version 2.0 (the "License");
0004 // you may not use this file except in compliance with the License.
0005 // You may obtain a copy of the License at
0006 //
0007 //      https://www.apache.org/licenses/LICENSE-2.0
0008 //
0009 // Unless required by applicable law or agreed to in writing, software
0010 // distributed under the License is distributed on an "AS IS" BASIS,
0011 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
0012 // See the License for the specific language governing permissions and
0013 // limitations under the License.
0014
0015 #ifndef ABSL_STRINGS_INTERNAL_CORDZ_STATISTICS_H_
0016 #define ABSL_STRINGS_INTERNAL_CORDZ_STATISTICS_H_
0017
0018 #include <cstdint>
0019
0020 #include "absl/base/config.h"
0021 #include "absl/strings/internal/cordz_update_tracker.h"
0022
0023 namespace absl {
0024 ABSL_NAMESPACE_BEGIN
0025 namespace cord_internal {
0026
0027 // CordzStatistics captures some meta information about a Cord's shape.
0028 struct CordzStatistics {
0029   using MethodIdentifier = CordzUpdateTracker::MethodIdentifier;
0030
0031   // Node counts information
0032   struct NodeCounts {
0033     size_t flat = 0;       // #flats
0034     size_t flat_64 = 0;    // #flats up to 64 bytes
0035     size_t flat_128 = 0;   // #flats up to 128 bytes
0036     size_t flat_256 = 0;   // #flats up to 256 bytes
0037     size_t flat_512 = 0;   // #flats up to 512 bytes
0038     size_t flat_1k = 0;    // #flats up to 1K bytes
0039     size_t external = 0;   // #external reps
0040     size_t substring = 0;  // #substring reps
0041     size_t concat = 0;     // #concat reps
0042     size_t ring = 0;       // #ring buffer reps
0043     size_t btree = 0;      // #btree reps
0044     size_t crc = 0;        // #crc reps
0045   };
0046
0047   // The size of the cord in bytes. This matches the result of Cord::size().
0048   size_t size = 0;
0049
0050   // The estimated memory used by the sampled cord. This value matches the
0051   // value as reported by Cord::EstimatedMemoryUsage().
0052   // A value of 0 implies the property has not been recorded.
0053   size_t estimated_memory_usage = 0;
0054
0055   // The effective memory used by the sampled cord, inversely weighted by the
0056   // effective indegree of each allocated node. This is a representation of the
0057   // fair share of memory usage that should be attributed to the sampled cord.
0058   // This value is more useful for cases where one or more nodes are referenced
0059   // by multiple Cord instances, and for cases where a Cord includes the same
0060   // node multiple times (either directly or indirectly).
0061   // A value of 0 implies the property has not been recorded.
0062   size_t estimated_fair_share_memory_usage = 0;
0063
0064   // The total number of nodes referenced by this cord.
0065   // For ring buffer Cords, this includes the 'ring buffer' node.
0066   // For btree Cords, this includes all 'CordRepBtree' tree nodes as well as all
0067   // the substring, flat and external nodes referenced by the tree.
0068   // A value of 0 implies the property has not been recorded.
0069   size_t node_count = 0;
0070
0071   // Detailed node counts per type
0072   NodeCounts node_counts;
0073
0074   // The cord method responsible for sampling the cord.
0075   MethodIdentifier method = MethodIdentifier::kUnknown;
0076
0077   // The cord method responsible for sampling the parent cord if applicable.
0078   MethodIdentifier parent_method = MethodIdentifier::kUnknown;
0079
0080   // Update tracker tracking invocation count per cord method.
0081   CordzUpdateTracker update_tracker;
0082 };
0083
0084 }  // namespace cord_internal
0085 ABSL_NAMESPACE_END
0086 }  // namespace absl
0087
0088 #endif  // ABSL_STRINGS_INTERNAL_CORDZ_STATISTICS_H_