[coll] Improve column split tests with named threads. (#10735)

src/collective/loop.cc

@@ -14,6 +14,7 @@
 #include <thread>     // for thread
 #include <utility>    // for move
 
+#include "../common/threading_utils.h"      // for NameThread
 #include "xgboost/collective/poll_utils.h"  // for PollHelper
 #include "xgboost/collective/result.h"      // for Fail, Success
 #include "xgboost/collective/socket.h"      // for FailWithCode
@@ -271,5 +272,6 @@ Loop::Loop(std::chrono::seconds timeout) : timeout_{timeout} {
   worker_ = std::thread{[this] {
     this->Process();
   }};
+  common::NameThread(&worker_, "lw");
 }
 }  // namespace xgboost::collective

src/collective/tracker.cc

@@ -23,6 +23,7 @@
 #include <utility>    // for move, forward
 
 #include "../common/json_utils.h"
+#include "../common/threading_utils.h"  // for NameThread
 #include "comm.h"
 #include "protocol.h"  // for kMagic, PeerInfo
 #include "tracker.h"
@@ -143,6 +144,8 @@ Result RabitTracker::Bootstrap(std::vector<WorkerProxy>* p_workers) {
       Json::Dump(jnext, &str);
       worker.Send(StringView{str});
     });
+    std::string name = "tkbs_t-" + std::to_string(r);
+    common::NameThread(&bootstrap_threads.back(), name.c_str());
   }
 
   for (auto& t : bootstrap_threads) {