docs: Use with

FAQ.md

@@ -23,7 +23,7 @@
 - [Can I subclass basic types such as TimeFunction](#can-i-subclass-basic-types-such-as-timefunction)
 - [How can I change the compilation flags (for example, I want to change the optimization level from -O3 to -O0)](#how-can-i-change-the-compilation-flags-for-example-i-want-to-change-the-optimization-level-from--o3-to--o0)
 - [Is the jitted code IEEE-compliant](#is-the-jitted-code-ieee-compliant)
-- [Can I control the MPI domain decomposition?](#can-i-control-the-mpi-domain-decomposition)
+- [Can I control the MPI domain decomposition](#can-i-control-the-mpi-domain-decomposition)
 - [How should I use MPI on multi-socket machines](#how-should-I-use-MPI-on-multi-socket-machines)
 - [How do I make sure my code is "MPI safe"](#how-do-i-make-sure-my-code-is-MPI-safe)
 - [Why does my Operator kernel die suddenly](#why-does-my-operator-kernel-die-suddenly)

devito/logger.py

@@ -77,7 +77,7 @@ def set_log_level(level, comm=None):
     """
     from devito import configuration
 
-    if comm is not None:
+    if comm is not None and configuration['mpi']:
         if comm.rank != 0:
             logger.removeHandler(stream_handler)
             logger.addHandler(logging.NullHandler())

devito/operator/operator.py

@@ -5,6 +5,7 @@
 from cached_property import cached_property
 import ctypes
 
+from devito import switchconfig
 from devito.arch import compiler_registry, platform_registry
 from devito.data import default_allocator
 from devito.exceptions import InvalidOperator
@@ -856,8 +857,10 @@ def apply(self, **kwargs):
         # Post-process runtime arguments
         self._postprocess_arguments(args, **kwargs)
 
-        # Output summary of performance achieved
-        return self._emit_apply_profiling(args)
+        # Output summary of performance achieved and
+        # temporarily drop MPI for printing arguments
+        with switchconfig(mpi=False):
+            return self._emit_apply_profiling(args)
 
     # Performance profiling
 
@@ -895,10 +898,8 @@ def _emit_timings(timings, indent=''):
     def _emit_apply_profiling(self, args):
         """Produce a performance summary of the profiled sections."""
 
-        # In case 'MPI0' is selected for logging, restrict result printing to one rank
-        temp = configuration['log-level']
-        if configuration['mpi']:
-            set_log_level(configuration['log-level'], comm=args.comm)
+        # In case MPI is used restrict result logging to one rank
+        set_log_level('DEBUG', comm=args.comm)
 
         # Rounder to 2 decimal places
         fround = lambda i: ceil(i * 100) / 100
@@ -993,16 +994,7 @@ def lower_perfentry(v):
                     if a in args:
                         perf_args[a] = args[a]
                         break
-
-        if configuration['mpi']:
-            perf("Performance[mode=%s, mpi=%s] arguments: %s, " %
-                 (self._mode, configuration['mpi'], perf_args))
-        else:
-            perf("Performance[mode=%s] arguments: %s" % (self._mode, perf_args))
-
-        # Restore logging configuration to all ranks
-        if configuration['mpi']:
-            set_log_level(temp, comm=None)
+        perf("Performance[mode=%s] arguments: %s" % (self._mode, perf_args))
 
         return summary
 

devito/operator/profiling.py

@@ -473,7 +473,7 @@ def add_glb_vanilla(self, key, time):
         ops = sum(v.ops for v in self.input.values())
         traffic = sum(v.traffic for v in self.input.values())
 
-        if np.isnan(traffic):
+        if np.isnan(traffic) or traffic == 0:
             return
 
         gflops = float(ops)/10**9