crimson/os/alienstore: add default behaviour for alien threads affinities

currently, we allow alienstore to be scheduled on to any cpu cores other than
the starting three, as in most current tests we use the those cores for crimson-osd
seastar threads

Signed-off-by: Xuehan Xu <xxhdx1985126@gmail.com>

diff --git a/src/crimson/os/alienstore/alien_store.cc b/src/crimson/os/alienstore/alien_store.cc
index ceac8cdafb80b494e850f73e31fbb0d8f4a707eb..e37d8a1f4f204ea6342660de3161152f05f9bb79 100644 (file)
--- a/src/crimson/os/alienstore/alien_store.cc
+++ b/src/crimson/os/alienstore/alien_store.cc
@@ -66,6 +66,21 @@ AlienStore::AlienStore(const std::string& path, const ConfigValues& values)
   const auto num_threads =
     cct->_conf.get_val<uint64_t>("crimson_alien_op_num_threads");
   std::vector<uint64_t> cpu_cores = _parse_cpu_cores();
+
+  // cores except the first "N_CORES_FOR_SEASTAR" ones will
+  // be used for alien threads scheduling:
+  //   [0, N_CORES_FOR_SEASTAR) are reserved for seastar reactors
+  //   [N_CORES_FOR_SEASTAR, ..] are assigned to alien threads.
+  if (cpu_cores.empty()) {
+    if (long nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
+       nr_cpus > N_CORES_FOR_SEASTAR ) {
+      for (int i = N_CORES_FOR_SEASTAR; i < nr_cpus; i++) {
+        cpu_cores.push_back(i);
+      }
+    } else {
+      logger().error("{}: unable to get nproc: {}", __func__, errno);
+    }
+  }
   tp = std::make_unique<crimson::os::ThreadPool>(num_threads, 128, cpu_cores);
 }
 

diff --git a/src/crimson/os/alienstore/alien_store.h b/src/crimson/os/alienstore/alien_store.h
index 08790c5fdfa6eb94023553bc4fbf27f62cf1e6d8..bc5376e0f6cdcd0a75ac5a12b9fd8883eff9bd8f 100644 (file)
--- a/src/crimson/os/alienstore/alien_store.h
+++ b/src/crimson/os/alienstore/alien_store.h
@@ -113,6 +113,9 @@ public:
     const ghobject_t& oid) final;
 
 private:
+  // number of cores that are PREVENTED from being scheduled
+  // to run alien store threads.
+  static constexpr int N_CORES_FOR_SEASTAR = 3;
   constexpr static unsigned MAX_KEYS_PER_OMAP_GET_CALL = 32;
   mutable std::unique_ptr<crimson::os::ThreadPool> tp;
   const std::string path;