Merge bitcoin/bitcoin#25456: rpc: Use steady_clock for getrpcinfo durations

fabae35 rpc: Use steady_clock for getrpcinfo durations (MacroFake)

Pull request description:

  Currently it uses `GetTimeMicros`, which is the system time. Using steady time instead, makes the code type safe and avoids spurious offsets when the system time adjusts.

ACKs for top commit:
  laanwj:
    Code review ACK fabae35
  w0xlt:
    Code Review ACK bitcoin/bitcoin@fabae35
  shaavan:
    Code Review ACK fabae35

Tree-SHA512: eb25fe3e69bf42ec8a2d4aaa69b435de7654b0d07218ce3e0c03ebaef6eb7f713128779057d012621773a34675a81f5757e7b2502c13b82adaf6e2df970d8c66

Author: MacroFake

src/rpc/server.cpp

@@ -11,14 +11,18 @@
 #include <util/strencodings.h>
 #include <util/string.h>
 #include <util/system.h>
+#include <util/time.h>
 
 #include <boost/signals2/signal.hpp>
 
 #include <cassert>
-#include <memory> // for unique_ptr
+#include <chrono>
+#include <memory>
 #include <mutex>
 #include <unordered_map>
 
+using SteadyClock = std::chrono::steady_clock;
+
 static GlobalMutex g_rpc_warmup_mutex;
 static std::atomic<bool> g_rpc_running{false};
 static bool fRPCInWarmup GUARDED_BY(g_rpc_warmup_mutex) = true;
@@ -33,7 +37,7 @@ static bool ExecuteCommand(const CRPCCommand& command, const JSONRPCRequest& req
 struct RPCCommandExecutionInfo
 {
     std::string method;
-    int64_t start;
+    SteadyClock::time_point start;
 };
 
 struct RPCServerInfo
@@ -50,7 +54,7 @@ struct RPCCommandExecution
     explicit RPCCommandExecution(const std::string& method)
     {
         LOCK(g_rpc_server_info.mutex);
-        it = g_rpc_server_info.active_commands.insert(g_rpc_server_info.active_commands.end(), {method, GetTimeMicros()});
+        it = g_rpc_server_info.active_commands.insert(g_rpc_server_info.active_commands.end(), {method, SteadyClock::now()});
     }
     ~RPCCommandExecution()
     {
@@ -231,7 +235,7 @@ static RPCHelpMan getrpcinfo()
     for (const RPCCommandExecutionInfo& info : g_rpc_server_info.active_commands) {
         UniValue entry(UniValue::VOBJ);
         entry.pushKV("method", info.method);
-        entry.pushKV("duration", GetTimeMicros() - info.start);
+        entry.pushKV("duration", int64_t{Ticks<std::chrono::microseconds>(SteadyClock::now() - info.start)});
         active_commands.push_back(entry);
     }
 

src/util/time.h

@@ -40,10 +40,15 @@ void UninterruptibleSleep(const std::chrono::microseconds& n);
  * This helper is used to convert durations/time_points before passing them over an
  * interface that doesn't support std::chrono (e.g. RPC, debug log, or the GUI)
  */
+template <typename Dur1, typename Dur2>
+constexpr auto Ticks(Dur2 d)
+{
+    return std::chrono::duration_cast<Dur1>(d).count();
+}
 template <typename Duration, typename Timepoint>
 constexpr auto TicksSinceEpoch(Timepoint t)
 {
-    return std::chrono::time_point_cast<Duration>(t).time_since_epoch().count();
+    return Ticks<Duration>(t.time_since_epoch());
 }
 constexpr int64_t count_seconds(std::chrono::seconds t) { return t.count(); }
 constexpr int64_t count_milliseconds(std::chrono::milliseconds t) { return t.count(); }