arch: Add Platform.suggested_alignment

devito/arch/archinfo.py

@@ -607,6 +607,11 @@ class Platform(object):
     max_mem_trans_nbytes = None
     """Maximum memory transaction size in bytes."""
 
+    suggested_alignment = None
+    """
+    The dimension along which data should be aligned for optimal performance.
+    """
+
     def __init__(self, name):
         self.name = name
 
@@ -658,9 +663,13 @@ def max_mem_trans_size(self, dtype):
 
 class Cpu64(Platform):
 
-    # The vast majority of CPUs have a 64-byte cache line
+    # The vast majority of CPUs have a 64-byte cache line size
     max_mem_trans_nbytes = 64
 
+    # The vast majority of CPUs expect the data's contiguous dimension to be
+    # aligned to the cache line size
+    suggested_alignment = '1-stride'  # AKA contiguous dimension
+
     # The known ISAs are to be provided by the subclasses
     known_isas = ()
 
@@ -808,6 +817,9 @@ class IntelDevice(Device):
 
     max_mem_trans_nbytes = 64
 
+    #TODO
+    suggested_alignment = None
+
     @property
     def march(self):
         return ''
@@ -816,6 +828,7 @@ def march(self):
 class NvidiaDevice(Device):
 
     max_mem_trans_nbytes = 128
+    suggested_alignment = 'max-stride'
 
     @cached_property
     def march(self):
@@ -830,6 +843,7 @@ def march(self):
 class AmdDevice(Device):
 
     max_mem_trans_nbytes = 256
+    suggested_alignment = 'max-stride'
 
     @cached_property
     def march(cls):