1 // -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
2 // vim: ts=8 sw=2 smarttab
5 * Copyright (C) 2017 Red Hat Inc.
16 #include <condition_variable>
18 #include "run_every.h"
19 #include "dmclock_util.h"
20 #include "dmclock_recs.h"
26 Counter delta_prev_req;
31 ServerInfo(Counter _delta_prev_req,
32 Counter _rho_prev_req) :
33 delta_prev_req(_delta_prev_req),
34 rho_prev_req(_rho_prev_req),
41 inline void req_update(Counter delta, Counter rho) {
42 delta_prev_req = delta;
48 inline void resp_update(PhaseType phase) {
50 if (phase == PhaseType::reservation) ++my_rho;
55 // S is server identifier type
57 class ServiceTracker {
58 // we don't want to include gtest.h just for FRIEND_TEST
59 friend class dmclock_client_server_erase_Test;
61 using TimePoint = decltype(std::chrono::steady_clock::now());
62 using Duration = std::chrono::milliseconds;
63 using MarkPoint = std::pair<TimePoint,Counter>;
65 Counter delta_counter; // # reqs completed
66 Counter rho_counter; // # reqs completed via reservation
67 std::map<S,ServerInfo> server_map;
68 mutable std::mutex data_mtx; // protects Counters and map
70 using DataGuard = std::lock_guard<decltype(data_mtx)>;
74 std::deque<MarkPoint> clean_mark_points;
75 Duration clean_age; // age at which ServerInfo cleaned
77 // NB: All threads declared at end, so they're destructed firs!
79 std::unique_ptr<RunEvery> cleaning_job;
84 // we have to start the counters at 1, as 0 is used in the
86 template<typename Rep, typename Per>
87 ServiceTracker(std::chrono::duration<Rep,Per> _clean_every,
88 std::chrono::duration<Rep,Per> _clean_age) :
91 clean_age(std::chrono::duration_cast<Duration>(_clean_age))
94 std::unique_ptr<RunEvery>(
95 new RunEvery(_clean_every,
96 std::bind(&ServiceTracker::do_clean, this)));
100 // the reason we're overloading the constructor rather than
101 // using default values for the arguments is so that callers
102 // have to either use all defaults or specify all timings; with
103 // default arguments they could specify some without others
105 ServiceTracker(std::chrono::minutes(5), std::chrono::minutes(10))
112 * Incorporates the RespParams received into the various counter.
114 void track_resp(const S& server_id, const PhaseType& phase) {
115 DataGuard g(data_mtx);
117 auto it = server_map.find(server_id);
118 if (server_map.end() == it) {
119 // this code can only run if a request did not precede the
120 // response or if the record was cleaned up b/w when
121 // the request was made and now
122 ServerInfo si(delta_counter, rho_counter);
123 si.resp_update(phase);
124 server_map.emplace(server_id, si);
126 it->second.resp_update(phase);
130 if (PhaseType::reservation == phase) {
137 * Returns the ReqParams for the given server.
139 ReqParams get_req_params(const S& server) {
140 DataGuard g(data_mtx);
141 auto it = server_map.find(server);
142 if (server_map.end() == it) {
143 server_map.emplace(server, ServerInfo(delta_counter, rho_counter));
144 return ReqParams(1, 1);
147 1 + delta_counter - it->second.delta_prev_req - it->second.my_delta;
149 1 + rho_counter - it->second.rho_prev_req - it->second.my_rho;
151 it->second.req_update(delta_counter, rho_counter);
153 return ReqParams(uint32_t(delta), uint32_t(rho));
160 * This is being called regularly by RunEvery. Every time it's
161 * called it notes the time and delta counter (mark point) in a
162 * deque. It also looks at the deque to find the most recent
163 * mark point that is older than clean_age. It then walks the
164 * map and delete all server entries that were last used before
168 TimePoint now = std::chrono::steady_clock::now();
169 DataGuard g(data_mtx);
170 clean_mark_points.emplace_back(MarkPoint(now, delta_counter));
172 Counter earliest = 0;
173 auto point = clean_mark_points.front();
174 while (point.first <= now - clean_age) {
175 earliest = point.second;
176 clean_mark_points.pop_front();
177 point = clean_mark_points.front();
181 for (auto i = server_map.begin();
182 i != server_map.end();
185 if (i2->second.delta_prev_req <= earliest) {
186 server_map.erase(i2);
191 }; // class ServiceTracker