shm: add APIs for implementing keep-alive process

2025-10-15 17:41:45 +00:00 · 2021-12-09 00:11:14 +01:00
parent eb4620b1ec
commit 692576a5b1
19 changed files with 872 additions and 452 deletions
--- a/examples/region/keep-alive.cxx
+++ b/examples/region/keep-alive.cxx
@@ -0,0 +1,108 @@
+/********************************************************************************
+ *    Copyright (C) 2021 GSI Helmholtzzentrum fuer Schwerionenforschung GmbH    *
+ *                                                                              *
+ *              This software is distributed under the terms of the             *
+ *              GNU Lesser General Public Licence (LGPL) version 3,             *
+ *                  copied verbatim in the file "LICENSE"                       *
+ ********************************************************************************/
+#include <fairmq/shmem/Common.h>
+#include <fairmq/shmem/UnmanagedRegion.h>
+#include <fairmq/shmem/Segment.h>
+#include <fairmq/shmem/Monitor.h>
+
+#include <fairmq/tools/Unique.h>
+
+#include <fairlogger/Logger.h>
+
+#include <csignal>
+
+#include <chrono>
+#include <string>
+#include <thread>
+
+using namespace std;
+
+namespace
+{
+    volatile sig_atomic_t gStopping = 0;
+}
+
+void signalHandler(int /* signal */)
+{
+    gStopping = 1;
+}
+
+struct ShmRemover
+{
+    ShmRemover(std::string _shmId) : shmId(std::move(_shmId)) {}
+    ~ShmRemover()
+    {
+        // This will clean all segments, regions and any other shmem objects belonging to this shmId
+        fair::mq::shmem::Monitor::Cleanup(fair::mq::shmem::ShmId{shmId});
+    }
+
+    std::string shmId;
+};
+
+int main(int /* argc */, char** /* argv */)
+{
+    fair::Logger::SetConsoleColor(true);
+
+    signal(SIGINT, signalHandler);
+    signal(SIGTERM, signalHandler);
+
+    try {
+        const string session = "default"; // to_string(fair::mq::tools::UuidHash());
+        // generate shmId out of session id + user id (geteuid).
+        const string shmId = fair::mq::shmem::makeShmIdStr(session);
+
+        const uint16_t s1id = 0;
+        const uint64_t s1size = 100000000;
+        const uint16_t s2id = 1;
+        const uint64_t s2size = 200000000;
+
+        const uint16_t r1id = 0;
+        const uint64_t r1size = 100000000;
+        const uint16_t r2id = 1;
+        const uint64_t r2size = 200000000;
+
+        // cleanup when done
+        ShmRemover shmRemover(shmId);
+
+        // managed segments
+        fair::mq::shmem::Segment segment1(shmId, s1id, s1size, fair::mq::shmem::rbTreeBestFit);
+        segment1.Lock();
+        segment1.Zero();
+        LOG(info) << "Created segment " << s1id << " of size " << segment1.GetSize() << " starting at " << segment1.GetData();
+
+        fair::mq::shmem::Segment segment2(shmId, s2id, s2size, fair::mq::shmem::rbTreeBestFit);
+        segment2.Lock();
+        segment2.Zero();
+        LOG(info) << "Created segment " << s2id << " of size " << segment2.GetSize() << " starting at " << segment2.GetData();
+
+        // unmanaged regions
+        fair::mq::shmem::UnmanagedRegion region1(shmId, r1id, r1size);
+        region1.Lock();
+        region1.Zero();
+        LOG(info) << "Created region " << r1id << " of size " << region1.GetSize() << " starting at " << region1.GetData();
+
+        fair::mq::shmem::UnmanagedRegion region2(shmId, r2id, r2size);
+        region2.Lock();
+        region2.Zero();
+        LOG(info) << "Created region " << r2id << " of size " << region2.GetSize() << " starting at " << region2.GetData();
+
+        // for a "soft reset" call (shmem should not be in active use by (no messages in flight) devices during this call):
+        // fair::mq::shmem::Monitor::ResetContent(fair::mq::shmem::ShmId{shmId});
+
+        while (!gStopping) {
+            std::this_thread::sleep_for(std::chrono::milliseconds(50));
+        }
+
+        LOG(info) << "stopping.";
+    } catch (exception& e) {
+        LOG(error) << "Unhandled Exception reached the top of main: " << e.what() << ", application will now exit";
+        return 2;
+    }
+
+    return 0;
+}