diff --git a/examples/analyse_tasks.py b/examples/analyse_tasks.py
index 17816cab62a343711abee14e0c9d6b7e70ce8e5c..d28553173ebb636a99c96082c1eb35ffedca7d6d 100755
--- a/examples/analyse_tasks.py
+++ b/examples/analyse_tasks.py
@@ -56,6 +56,11 @@ TASKTYPES = ["none", "sort", "self", "pair", "sub_self", "sub_pair",
 SUBTYPES = ["none", "density", "gradient", "force", "grav", "external_grav",
             "tend", "xv", "rho", "gpart", "multipole", "spart", "count"]
 
+SIDS = ["(-1,-1,-1)", "(-1,-1, 0)", "(-1,-1, 1)", "(-1, 0,-1)",
+        "(-1, 0, 0)", "(-1, 0, 1)", "(-1, 1,-1)", "(-1, 1, 0)",
+        "(-1, 1, 1)", "( 0,-1,-1)", "( 0,-1, 0)", "( 0,-1, 1)",
+        "( 0, 0,-1)"]
+
 #  Read input.
 data = pl.loadtxt( infile )
 
@@ -66,11 +71,17 @@ print "# Maximum thread id:", maxthread
 full_step = data[0,:]
 tic_step = int(full_step[4])
 toc_step = int(full_step[5])
+updates = int(full_step[6])
+g_updates = int(full_step[7])
+s_updates = int(full_step[8])
 CPU_CLOCK = float(full_step[-1]) / 1000.0
 data = data[1:,:]
 if args.verbose:
-    print "CPU frequency:", CPU_CLOCK * 1000.0
-
+    print "# CPU frequency:", CPU_CLOCK * 1000.0
+print "#   updates:", updates
+print "# g_updates:", g_updates
+print "# s_updates:", s_updates
+    
 #  Avoid start and end times of zero.
 data = data[data[:,4] != 0]
 data = data[data[:,5] != 0]
@@ -78,6 +89,7 @@ data = data[data[:,5] != 0]
 #  Calculate the time range.
 total_t = (toc_step - tic_step)/ CPU_CLOCK
 print "# Data range: ", total_t, "ms"
+print
 
 #  Correct times to relative values.
 start_t = float(tic_step)
@@ -90,15 +102,16 @@ for i in range(maxthread):
     tasks[i] = []
 
 #  Gather into by thread data.
-num_lines = pl.size(data) / 10
+num_lines = pl.size(data) / pl.size(full_step)
 for line in range(num_lines):
     thread = int(data[line,0])
     tic = int(data[line,4]) / CPU_CLOCK
     toc = int(data[line,5]) / CPU_CLOCK
     tasktype = int(data[line,1])
     subtype = int(data[line,2])
+    sid = int(data[line, -1])
 
-    tasks[thread].append([tic,toc,tasktype,subtype])
+    tasks[thread].append([tic,toc,tasktype,subtype, sid])
 
 #  Sort by tic and gather used thread ids.
 threadids = []
@@ -110,10 +123,11 @@ for i in range(maxthread):
 #  Times per task.
 print "# Task times:"
 print "# -----------"
-print "# {0:<16s}: {1:>7s} {2:>9s} {3:>9s} {4:>9s} {5:>9s} {6:>9s}"\
+print "# {0:<17s}: {1:>7s} {2:>9s} {3:>9s} {4:>9s} {5:>9s} {6:>9s}"\
       .format("type/subtype", "count","minimum", "maximum",
               "sum", "mean", "percent")
 alltasktimes = {}
+sidtimes = {}
 for i in threadids:
     tasktimes = {}
     for task in tasks[i]:
@@ -127,12 +141,19 @@ for i in threadids:
             alltasktimes[key] = []
         alltasktimes[key].append(dt)
 
+        my_sid = task[4]
+        if my_sid > -1:
+            if not my_sid in sidtimes:
+                sidtimes[my_sid] = []
+            sidtimes[my_sid].append(dt)
+                
+        
     print "# Thread : ", i
     for key in sorted(tasktimes.keys()):
         taskmin = min(tasktimes[key])
         taskmax = max(tasktimes[key])
         tasksum = sum(tasktimes[key])
-        print "{0:18s}: {1:7d} {2:9.4f} {3:9.4f} {4:9.4f} {5:9.4f} {6:9.2f}"\
+        print "{0:19s}: {1:7d} {2:9.4f} {3:9.4f} {4:9.4f} {5:9.4f} {6:9.2f}"\
               .format(key, len(tasktimes[key]), taskmin, taskmax, tasksum,
                       tasksum / len(tasktimes[key]), tasksum / total_t * 100.0)
     print
@@ -142,12 +163,36 @@ for key in sorted(alltasktimes.keys()):
     taskmin = min(alltasktimes[key])
     taskmax = max(alltasktimes[key])
     tasksum = sum(alltasktimes[key])
-    print "{0:18s}: {1:7d} {2:9.4f} {3:9.4f} {4:9.4f} {5:9.4f} {6:9.2f}"\
+    print "{0:19s}: {1:7d} {2:9.4f} {3:9.4f} {4:9.4f} {5:9.4f} {6:9.2f}"\
           .format(key, len(alltasktimes[key]), taskmin, taskmax, tasksum,
                   tasksum / len(alltasktimes[key]),
                   tasksum / (len(threadids) * total_t) * 100.0)
 print
 
+# For pairs, show stuf sorted by SID
+print "# By SID (all threads): "
+print "# {0:<17s}: {1:>7s} {2:>9s} {3:>9s} {4:>9s} {5:>9s} {6:>9s}"\
+    .format("Pair/Sub-pair SID", "count","minimum", "maximum",
+            "sum", "mean", "percent")
+
+for sid in range(0,13):
+    if sid in sidtimes:
+        sidmin = min(sidtimes[sid])
+        sidmax = max(sidtimes[sid])
+        sidsum = sum(sidtimes[sid])
+        sidcount = len(sidtimes[sid])
+        sidmean = sidsum / sidcount
+    else:
+        sidmin = 0.
+        sidmax = 0.
+        sidsum = 0.
+        sidcount = 0
+        sidmean = 0.
+    print "{0:3d} {1:15s}: {2:7d} {3:9.4f} {4:9.4f} {5:9.4f} {6:9.4f} {7:9.2f}"\
+        .format(sid, SIDS[sid], sidcount, sidmin, sidmax, sidsum,
+                sidmean, sidsum / (len(threadids) * total_t) * 100.0)   
+print
+
 #  Dead times.
 print "# Times not in tasks (deadtimes)"
 print "# ------------------------------"
diff --git a/examples/analyse_tasks_MPI.py b/examples/analyse_tasks_MPI.py
index c90c8caee6062fd83a8ff3bda3e760eee55b08e1..b78d73e879046b05b8a089f97c4c9c00a5f7bb79 100755
--- a/examples/analyse_tasks_MPI.py
+++ b/examples/analyse_tasks_MPI.py
@@ -42,6 +42,9 @@ parser.add_argument("input", help="Thread data file (-y output)")
 parser.add_argument("-v", "--verbose", dest="verbose",
                     help="Verbose output (default: False)",
                     default=False, action="store_true")
+parser.add_argument("-r", "--rank", dest="rank",
+                    help="Rank to process (default: all)",
+                    default="all", action="store")
 
 args = parser.parse_args()
 infile = args.input
@@ -56,17 +59,36 @@ TASKTYPES = ["none", "sort", "self", "pair", "sub_self", "sub_pair",
 SUBTYPES = ["none", "density", "gradient", "force", "grav", "external_grav",
             "tend", "xv", "rho", "gpart", "multipole", "spart", "count"]
 
+SIDS = ["(-1,-1,-1)", "(-1,-1, 0)", "(-1,-1, 1)", "(-1, 0,-1)",
+        "(-1, 0, 0)", "(-1, 0, 1)", "(-1, 1,-1)", "(-1, 1, 0)",
+        "(-1, 1, 1)", "( 0,-1,-1)", "( 0,-1, 0)", "( 0,-1, 1)",
+        "( 0, 0,-1)"]
+
 #  Read input.
 data = pl.loadtxt( infile )
 
 #  Get the CPU clock to convert ticks into milliseconds.
 full_step = data[0,:]
+updates = int(full_step[7])
+g_updates = int(full_step[8])
+s_updates = int(full_step[9])
 CPU_CLOCK = float(full_step[-1]) / 1000.0
 if args.verbose:
     print "# CPU frequency:", CPU_CLOCK * 1000.0
+print "#   updates:", updates
+print "# g_updates:", g_updates
+print "# s_updates:", s_updates
 
 nranks = int(max(data[:,0])) + 1
 print "# Number of ranks:", nranks
+if args.rank == "all":
+    ranks = range(nranks)
+else:
+    ranks = [int(args.rank)]
+    if ranks[0] >= nranks:
+        print "Error: maximum rank is " + str(nranks - 1)
+        sys.exit(1)
+
 maxthread = int(max(data[:,1])) + 1
 print "# Maximum thread id:", maxthread
 
@@ -74,8 +96,8 @@ print "# Maximum thread id:", maxthread
 sdata = data[data[:,5] != 0]
 sdata = data[data[:,6] != 0]
 
-#  Now we process all the ranks.
-for rank in range(nranks):
+#  Now we process the required ranks.
+for rank in ranks:
     print "# Rank", rank
     data = sdata[sdata[:,0] == rank]
 
@@ -92,6 +114,7 @@ for rank in range(nranks):
     #  Calculate the time range.
     total_t = (toc_step - tic_step)/ CPU_CLOCK
     print "# Data range: ", total_t, "ms"
+    print
 
     #  Correct times to relative values.
     start_t = float(tic_step)
@@ -105,15 +128,16 @@ for rank in range(nranks):
         tasks[i] = []
 
     #  Gather into by thread data.
-    num_lines = pl.size(data) / 12
+    num_lines = pl.shape(data)[0]
     for line in range(num_lines):
         thread = int(data[line,1])
         tic = int(data[line,5]) / CPU_CLOCK
         toc = int(data[line,6]) / CPU_CLOCK
         tasktype = int(data[line,2])
         subtype = int(data[line,3])
+        sid = int(data[line, -1])
 
-        tasks[thread].append([tic,toc,tasktype,subtype])
+        tasks[thread].append([tic,toc,tasktype,subtype, sid])
 
     #  Sort by tic and gather used threads.
     threadids = []
@@ -124,10 +148,12 @@ for rank in range(nranks):
     #  Times per task.
     print "# Task times:"
     print "# -----------"
-    print "# {0:<16s}: {1:>7s} {2:>9s} {3:>9s} {4:>9s} {5:>9s} {6:>9s}"\
+    print "# {0:<17s}: {1:>7s} {2:>9s} {3:>9s} {4:>9s} {5:>9s} {6:>9s}"\
           .format("type/subtype", "count","minimum", "maximum",
                   "sum", "mean", "percent")
+
     alltasktimes = {}
+    sidtimes = {}
     for i in threadids:
         tasktimes = {}
         for task in tasks[i]:
@@ -140,13 +166,19 @@ for rank in range(nranks):
             if not key in alltasktimes:
                 alltasktimes[key] = []
             alltasktimes[key].append(dt)
+            
+            my_sid = task[4]
+            if my_sid > -1:
+                if not my_sid in sidtimes:
+                    sidtimes[my_sid] = []
+                sidtimes[my_sid].append(dt)
 
         print "# Thread : ", i
         for key in sorted(tasktimes.keys()):
             taskmin = min(tasktimes[key])
             taskmax = max(tasktimes[key])
             tasksum = sum(tasktimes[key])
-            print "{0:18s}: {1:7d} {2:9.4f} {3:9.4f} {4:9.4f} {5:9.4f} {6:9.2f}"\
+            print "{0:19s}: {1:7d} {2:9.4f} {3:9.4f} {4:9.4f} {5:9.4f} {6:9.2f}"\
                   .format(key, len(tasktimes[key]), taskmin, taskmax, tasksum,
                           tasksum / len(tasktimes[key]), tasksum / total_t * 100.0)
         print
@@ -162,6 +194,30 @@ for rank in range(nranks):
                       tasksum / (len(threadids) * total_t) * 100.0)
     print
 
+    # For pairs, show stuf sorted by SID
+    print "# By SID (all threads): "
+    print "# {0:<17s}: {1:>7s} {2:>9s} {3:>9s} {4:>9s} {5:>9s} {6:>9s}"\
+        .format("Pair/Sub-pair SID", "count","minimum", "maximum",
+                "sum", "mean", "percent")
+
+    for sid in range(0,13):
+        if sid in sidtimes:
+            sidmin = min(sidtimes[sid])
+            sidmax = max(sidtimes[sid])
+            sidsum = sum(sidtimes[sid])
+            sidcount = len(sidtimes[sid])
+            sidmean = sidsum / sidcount
+        else:
+            sidmin = 0.
+            sidmax = 0.
+            sidsum = 0.
+            sidcount = 0
+            sidmean = 0.
+        print "{0:3d} {1:15s}: {2:7d} {3:9.4f} {4:9.4f} {5:9.4f} {6:9.4f} {7:9.2f}"\
+            .format(sid, SIDS[sid], sidcount, sidmin, sidmax, sidsum,
+                    sidmean, sidsum / (len(threadids) * total_t) * 100.0)   
+    print
+
     #  Dead times.
     print "# Times not in tasks (deadtimes)"
     print "# ------------------------------"
diff --git a/examples/main.c b/examples/main.c
index 5a4e56ad4f5744345a7c2a61fbe008c8e750685b..4cc3a36d4cd32518902332e387220aeafaefcdfc 100644
--- a/examples/main.c
+++ b/examples/main.c
@@ -681,14 +681,16 @@ int main(int argc, char *argv[]) {
           /* Open file and position at end. */
           file_thread = fopen(dumpfile, "a");
 
-          fprintf(file_thread, " %03i 0 0 0 0 %lli %lli 0 0 0 0 %lli\n", myrank,
-                  e.tic_step, e.toc_step, cpufreq);
+          fprintf(file_thread, " %03i 0 0 0 0 %lli %lli %zi %zi %zi 0 0 %lli\n",
+                  myrank, e.tic_step, e.toc_step, e.updates, e.g_updates,
+                  e.s_updates, cpufreq);
           int count = 0;
           for (int l = 0; l < e.sched.nr_tasks; l++) {
             if (!e.sched.tasks[l].implicit && e.sched.tasks[l].toc != 0) {
               fprintf(
-                  file_thread, " %03i %i %i %i %i %lli %lli %i %i %i %i %i\n",
-                  myrank, e.sched.tasks[l].rid, e.sched.tasks[l].type,
+                  file_thread,
+                  " %03i %i %i %i %i %lli %lli %i %i %i %i %i %i\n", myrank,
+                  e.sched.tasks[l].rid, e.sched.tasks[l].type,
                   e.sched.tasks[l].subtype, (e.sched.tasks[l].cj == NULL),
                   e.sched.tasks[l].tic, e.sched.tasks[l].toc,
                   (e.sched.tasks[l].ci != NULL) ? e.sched.tasks[l].ci->count
@@ -699,7 +701,7 @@ int main(int argc, char *argv[]) {
                                                 : 0,
                   (e.sched.tasks[l].cj != NULL) ? e.sched.tasks[l].cj->gcount
                                                 : 0,
-                  e.sched.tasks[l].flags);
+                  e.sched.tasks[l].flags, e.sched.tasks[l].sid);
             }
             fflush(stdout);
             count++;
@@ -717,19 +719,21 @@ int main(int argc, char *argv[]) {
       FILE *file_thread;
       file_thread = fopen(dumpfile, "w");
       /* Add some information to help with the plots */
-      fprintf(file_thread, " %i %i %i %i %lli %lli %i %i %i %lli\n", -2, -1, -1,
-              1, e.tic_step, e.toc_step, 0, 0, 0, cpufreq);
+      fprintf(file_thread, " %i %i %i %i %lli %lli %zi %zi %zi %i %lli\n", -2,
+              -1, -1, 1, e.tic_step, e.toc_step, e.updates, e.g_updates,
+              e.s_updates, 0, cpufreq);
       for (int l = 0; l < e.sched.nr_tasks; l++) {
         if (!e.sched.tasks[l].implicit && e.sched.tasks[l].toc != 0) {
           fprintf(
-              file_thread, " %i %i %i %i %lli %lli %i %i %i %i\n",
+              file_thread, " %i %i %i %i %lli %lli %i %i %i %i %i\n",
               e.sched.tasks[l].rid, e.sched.tasks[l].type,
               e.sched.tasks[l].subtype, (e.sched.tasks[l].cj == NULL),
               e.sched.tasks[l].tic, e.sched.tasks[l].toc,
               (e.sched.tasks[l].ci == NULL) ? 0 : e.sched.tasks[l].ci->count,
               (e.sched.tasks[l].cj == NULL) ? 0 : e.sched.tasks[l].cj->count,
               (e.sched.tasks[l].ci == NULL) ? 0 : e.sched.tasks[l].ci->gcount,
-              (e.sched.tasks[l].cj == NULL) ? 0 : e.sched.tasks[l].cj->gcount);
+              (e.sched.tasks[l].cj == NULL) ? 0 : e.sched.tasks[l].cj->gcount,
+              e.sched.tasks[l].sid);
         }
       }
       fclose(file_thread);
diff --git a/examples/plot_tasks.py b/examples/plot_tasks.py
index 88f176687db8116cfd4370970769164985e4d366..e80c3635cf02d409c82960395261179e27cff853 100755
--- a/examples/plot_tasks.py
+++ b/examples/plot_tasks.py
@@ -78,7 +78,7 @@ PLOT_PARAMS = {"axes.labelsize": 10,
                "figure.figsize" : (args.width, args.height),
                "figure.subplot.left" : 0.03,
                "figure.subplot.right" : 0.995,
-               "figure.subplot.bottom" : 0.1,
+               "figure.subplot.bottom" : 0.09,
                "figure.subplot.top" : 0.99,
                "figure.subplot.wspace" : 0.,
                "figure.subplot.hspace" : 0.,
@@ -183,7 +183,7 @@ ecounter = []
 for i in range(nthread):
     ecounter.append(0)
 
-num_lines = pl.size(data) / 10
+num_lines = pl.size(data) / pl.size(full_step)
 for line in range(num_lines):
     thread = int(data[line,0])
 
@@ -243,21 +243,21 @@ for i in range(nthread):
 #  Legend and room for it.
 nrow = len(typesseen) / 5
 if not args.nolegend:
-    if len(typesseen) * 5 < nrow:
-        nrow = nrow + 1
     ax.fill_between([0, 0], nthread+0.5, nthread + nrow + 0.5, facecolor="white")
-    ax.set_ylim(0, nthread + nrow + 1)
-    ax.legend(loc=1, shadow=True, mode="expand", ncol=5)
-
+    ax.set_ylim(0, nthread + 0.5)
+    ax.legend(loc=1, shadow=True, bbox_to_anchor=(0., 1.05 ,1., 0.2), mode="expand", ncol=5)
+    box = ax.get_position()
+    ax.set_position([box.x0, box.y0, box.width, box.height*0.8])
+    
 # Start and end of time-step
 ax.plot([0, 0], [0, nthread + nrow + 1], 'k--', linewidth=1)
 ax.plot([end_t, end_t], [0, nthread + nrow + 1], 'k--', linewidth=1)
 
-ax.set_xlabel("Wall clock time [ms]")
+ax.set_xlabel("Wall clock time [ms]", labelpad=0.)
 if expand == 1:
-    ax.set_ylabel("Thread ID" )
+    ax.set_ylabel("Thread ID", labelpad=0 )
 else:
-    ax.set_ylabel("Thread ID * " + str(expand) )
+    ax.set_ylabel("Thread ID * " + str(expand), labelpad=0 )
 ax.set_yticks(pl.array(range(nthread)), True)
 
 loc = plticker.MultipleLocator(base=expand)
diff --git a/examples/plot_tasks_MPI.py b/examples/plot_tasks_MPI.py
index 83465aee87e8b641775d760fa4db2f06b125dd8b..85d7c54567a66c9c2151732e0e7a11c6580f958b 100755
--- a/examples/plot_tasks_MPI.py
+++ b/examples/plot_tasks_MPI.py
@@ -278,12 +278,12 @@ for rank in range(nranks):
 
     #  Legend and room for it.
     nrow = len(typesseen) / 5
-    if len(typesseen) * 5 < nrow:
-        nrow = nrow + 1
     ax.fill_between([0, 0], nethread+0.5, nethread + nrow + 0.5, facecolor="white")
-    ax.set_ylim(0, nethread + nrow + 1)
+    ax.set_ylim(0, nethread + 0.5)
     if data.size > 0:
-        ax.legend(loc=1, shadow=True, mode="expand", ncol=5)
+        ax.legend(loc=1, shadow=True, bbox_to_anchor=(0., 1.05 ,1., 0.2), mode="expand", ncol=5)
+        box = ax.get_position()
+        ax.set_position([box.x0, box.y0, box.width, box.height*0.8])
 
     # Start and end of time-step
     ax.plot([0, 0], [0, nethread + nrow + 1], 'k--', linewidth=1)
diff --git a/examples/process_plot_tasks_MPI b/examples/process_plot_tasks_MPI
index b2672b3711823eb87d0bede5b1ffd8945a735f98..691822ebc33b43450d69b06e49c2c95bb0683045 100755
--- a/examples/process_plot_tasks_MPI
+++ b/examples/process_plot_tasks_MPI
@@ -62,7 +62,9 @@ nrank=$(($nrank-1))
 #  And process them,
 echo "Processing thread info files..."
 echo $list | xargs -P $NPROCS -n 3 /bin/bash -c "./plot_tasks_MPI.py --expand 1 --limit $TIMERANGE \$0 \$2 "
-echo $list | xargs -P $NPROCS -n 3 /bin/bash -c "./analyse_tasks_MPI.py \$0 > \$2.stats"
+for i in $(seq 0 $nrank); do
+    echo $list | xargs -P $NPROCS -n 3 /bin/bash -c "./analyse_tasks_MPI.py -r $i \$0 > \$2${i}.stats"
+done
 
 echo "Writing output index.html file"
 #  Construct document - serial.
@@ -93,7 +95,7 @@ EOF2
 <img src="step${s}r${i}.png">
 <pre>
 EOF2
-cat step${s}r.stats >> step${s}r${i}.html
+cat step${s}r${i}.stats >> step${s}r${i}.html
 cat <<EOF2 >> step${s}r${i}.html
 </pre>
 </body>
diff --git a/src/engine.c b/src/engine.c
index 1281470dbb0c8a506997929fd01e9c9eb5343f71..827778100fcdea0a89afb210677bf26fc9acd8b8 100644
--- a/src/engine.c
+++ b/src/engine.c
@@ -331,7 +331,8 @@ static void *engine_do_redistribute(int *counts, char *parts,
       for (int k = 0; k < 2 * nr_nodes; k++) {
         char buff[MPI_MAX_ERROR_STRING];
         MPI_Error_string(stats[k].MPI_ERROR, buff, &res);
-        message("request from source %i, tag %i has error '%s'.", stats[k].MPI_SOURCE, stats[k].MPI_TAG, buff);
+        message("request from source %i, tag %i has error '%s'.",
+                stats[k].MPI_SOURCE, stats[k].MPI_TAG, buff);
       }
       error("Failed during waitall for part data.");
     }
@@ -605,7 +606,6 @@ void engine_redistribute(struct engine *e) {
   if (s->nr_gparts > 0)
     space_gparts_sort(s, g_dest, s->nr_gparts, 0, nr_nodes - 1, e->verbose);
 
-
 #ifdef SWIFT_DEBUG_CHECKS
   /* Verify that the gpart have been sorted correctly. */
   for (size_t k = 0; k < s->nr_gparts; k++) {
@@ -621,8 +621,8 @@ void engine_redistribute(struct engine *e) {
     const int new_node = c->nodeID;
 
     if (g_dest[k] != new_node)
-        error("gpart's new node index not matching sorted index (%d != %d).",
-              g_dest[k], new_node);
+      error("gpart's new node index not matching sorted index (%d != %d).",
+            g_dest[k], new_node);
 
     if (gp->x[0] < c->loc[0] || gp->x[0] > c->loc[0] + c->width[0] ||
         gp->x[1] < c->loc[1] || gp->x[1] > c->loc[1] + c->width[1] ||
diff --git a/src/runner.c b/src/runner.c
index 08605b9093e93e8988ca462e92507a7d8f5fc068..735865bad088f09e01756a4e9c6ee4c2f81ab4aa 100644
--- a/src/runner.c
+++ b/src/runner.c
@@ -1739,9 +1739,19 @@ void *runner_main(void *data) {
       struct cell *ci = t->ci;
       struct cell *cj = t->cj;
 
-/* Mark the thread we run on */
 #ifdef SWIFT_DEBUG_TASKS
+      /* Mark the thread we run on */
       t->rid = r->cpuid;
+
+      /* And recover the pair direction */
+      if (t->type == task_type_pair || t->type == task_type_sub_pair) {
+        struct cell *ci_temp = ci;
+        struct cell *cj_temp = cj;
+        double shift[3];
+        t->sid = space_getsid(e->s, &ci_temp, &cj_temp, shift);
+      } else {
+        t->sid = -1;
+      }
 #endif
 
 /* Check that we haven't scheduled an inactive task */
diff --git a/src/task.h b/src/task.h
index 052f3e8036381441e283d3f7847d09e98ec1dac2..cd15e09cc5a1b597f96dad7dfeaa479f721f0c8b 100644
--- a/src/task.h
+++ b/src/task.h
@@ -162,6 +162,9 @@ struct task {
   /*! ID of the queue or runner owning this task */
   short int rid;
 
+  /*! Information about the direction of the pair task */
+  short int sid;
+
   /*! Start and end time of this task */
   ticks tic, toc;
 #endif