Profiler on linux: use SA_RESTART signal flag to have most of the syscalls restarted for us.

src/platform-linux.cc

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 838 matching lines @@
 
 void Sampler::Start() {
   // There can only be one active sampler at the time on POSIX
   // platforms.
   if (active_sampler_ != NULL) return;
 
   // Request profiling signals.
   struct sigaction sa;
   sa.sa_sigaction = ProfilerSignalHandler;
   sigemptyset(&sa.sa_mask);
-  sa.sa_flags = SA_SIGINFO;
+  sa.sa_flags = SA_RESTART | SA_SIGINFO;
   if (sigaction(SIGPROF, &sa, &data_->old_signal_handler_) != 0) return;
   data_->signal_handler_installed_ = true;
 
   // Start a thread that sends SIGPROF signal to VM thread.
   // Sending the signal ourselves instead of relying on itimer provides
   // much better accuracy.
   active_ = true;
   if (pthread_create(
           &data_->signal_sender_thread_, NULL, SenderEntry, data_) == 0) {
     data_->signal_sender_launched_ = true;
@@ skipping 21 matching lines @@
   }
 
   // This sampler is no longer the active sampler.
   active_sampler_ = NULL;
 }
 
 
 #endif  // ENABLE_LOGGING_AND_PROFILING
 
 } }  // namespace v8::internal