Merge branch 'part_alignment' into 'master'

Align critical structures on 128 bytes and make all their sizes multiples of 32 bytes.

Here is another one for you.

Following the discussion we had earlier about the task structure I have gone through the rest of the code and made sure everything important is aligned on 128 bytes. 

See merge request !240

src/Makefile.am

@@ -55,7 +55,7 @@ AM_SOURCES = space.c runner.c queue.c task.c cell.c engine.c \
     runner_doiact_fft.c threadpool.c cooling.c
 
 # Include files for distribution, not installation.
-nobase_noinst_HEADERS = approx_math.h atomic.h cycle.h error.h inline.h kernel_hydro.h kernel_gravity.h \
+nobase_noinst_HEADERS = align.h approx_math.h atomic.h cycle.h error.h inline.h kernel_hydro.h kernel_gravity.h \
 		 kernel_long_gravity.h vector.h runner_doiact.h runner_doiact_grav.h runner_doiact_fft.h \
                  units.h intrinsics.h minmax.h kick.h timestep.h drift.h adiabatic_index.h io_properties.h \
 		 dimension.h equation_of_state.h \

src/align.h

+/*******************************************************************************
+ * This file is part of SWIFT.
+ * Copyright (c) 2016 Matthieu Schaller (matthieu.schaller@durham.ac.uk).
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published
+ * by the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ ******************************************************************************/
+#ifndef SWIFT_ALIGN_H
+#define SWIFT_ALIGN_H
+
+/**
+ * @brief Defines alignment of structures
+ */
+#define SWIFT_STRUCT_ALIGN __attribute__((aligned(32)))
+
+#endif /* SWIFT_ALIGN_H */

src/cell.h

@@ -30,6 +30,7 @@
 #include <stddef.h>
 
 /* Local includes. */
+#include "align.h"
 #include "lock.h"
 #include "multipole.h"
 #include "part.h"
@@ -44,7 +45,7 @@ struct space;
  * The maximum was lowered by a further factor of 2 to be on the safe side.*/
 #define cell_max_tag (1 << 29)
 
-#define cell_align 32
+#define cell_align 128
 
 /* Global variables. */
 extern int cell_next_tag;
@@ -74,7 +75,8 @@ struct pcell {
 
   /* Relative indices of the cell's progeny. */
   int progeny[8];
-};
+
+} SWIFT_STRUCT_ALIGN;
 
 /* Structure to store the data of a single cell. */
 struct cell {
@@ -208,7 +210,7 @@ struct cell {
 
 #endif
 
-} __attribute__((aligned(cell_align)));
+} SWIFT_STRUCT_ALIGN;
 
 /* Convert cell location to ID. */
 #define cell_getid(cdim, i, j, k) \

src/gravity/Default/gravity_part.h

@@ -53,6 +53,6 @@ struct gpart {
      which this gpart is linked. */
   long long id_or_neg_offset;
 
-} __attribute__((aligned(gpart_align)));
+} SWIFT_STRUCT_ALIGN;
 
 #endif /* SWIFT_DEFAULT_GRAVITY_PART_H */

src/hydro/Default/hydro_part.h

@@ -33,7 +33,7 @@ struct xpart {
   /* Old density. */
   float omega;
 
-} __attribute__((aligned(xpart_align)));
+} SWIFT_STRUCT_ALIGN;
 
 /* Data of a single particle. */
 struct part {
@@ -120,6 +120,6 @@ struct part {
   /* Pointer to corresponding gravity part. */
   struct gpart* gpart;
 
-} __attribute__((aligned(part_align)));
+} SWIFT_STRUCT_ALIGN;
 
 #endif /* SWIFT_DEFAULT_HYDRO_PART_H */

src/hydro/Gadget2/hydro_part.h

@@ -28,7 +28,7 @@ struct xpart {
   /* Velocity at the last full step. */
   float v_full[3];
 
-} __attribute__((aligned(xpart_align)));
+} SWIFT_STRUCT_ALIGN;
 
 /* Data of a single particle. */
 struct part {
@@ -110,6 +110,6 @@ struct part {
   /* Pointer to corresponding gravity part. */
   struct gpart* gpart;
 
-} __attribute__((aligned(part_align)));
+} SWIFT_STRUCT_ALIGN;
 
 #endif /* SWIFT_GADGET2_HYDRO_PART_H */

src/hydro/Gizmo/hydro_part.h

@@ -26,7 +26,7 @@ struct xpart {
   /* Velocity at the last full step. */
   float v_full[3];
 
-} __attribute__((aligned(xpart_align)));
+} SWIFT_STRUCT_ALIGN;
 
 /* Data of a single particle. */
 struct part {
@@ -196,4 +196,4 @@ struct part {
   /* Associated gravitas. */
   struct gpart *gpart;
 
-} __attribute__((aligned(part_align)));
+} SWIFT_STRUCT_ALIGN;

src/hydro/Minimal/hydro_part.h

@@ -47,7 +47,7 @@ struct xpart {
 
   float v_full[3]; /*!< Velocity at the last full step. */
 
-} __attribute__((aligned(xpart_align)));
+} SWIFT_STRUCT_ALIGN;
 
 /**
  * @brief Particle fields for the SPH particles
@@ -120,6 +120,6 @@ struct part {
 
   struct gpart* gpart; /*!< Pointer to corresponding gravity part. */
 
-} __attribute__((aligned(part_align)));
+} SWIFT_STRUCT_ALIGN;
 
 #endif /* SWIFT_MINIMAL_HYDRO_PART_H */

src/part.h

@@ -31,12 +31,13 @@
 #endif
 
 /* Local headers. */
+#include "align.h"
 #include "const.h"
 
 /* Some constants. */
-#define part_align 64
-#define xpart_align 32
-#define gpart_align 32
+#define part_align 128
+#define xpart_align 128
+#define gpart_align 128
 
 /* Import the right hydro particle definition */
 #if defined(MINIMAL_SPH)

src/task.h

@@ -26,6 +26,7 @@
 #include "../config.h"
 
 /* Includes. */
+#include "align.h"
 #include "cell.h"
 #include "cycle.h"
 
@@ -149,7 +150,7 @@ struct task {
   /*! Is this task implicit (i.e. does not do anything) ? */
   char implicit;
 
-} __attribute__((aligned(32)));
+} SWIFT_STRUCT_ALIGN;
 
 /* Function prototypes. */
 void task_unlock(struct task *t);