diff --git a/lib/PerconaTest.pm b/lib/PerconaTest.pm
index e5eea85c..982b5f8e 100644
--- a/lib/PerconaTest.pm
+++ b/lib/PerconaTest.pm
@@ -483,6 +483,10 @@ sub no_diff {
          `sed $sed_args $tmp_file`;
       }
    }
+   if ( defined(my $sort_args = $args{sort}) ) {
+      `cat $tmp_file | sort $sort_args > $tmp_file-2`;
+      `mv $tmp_file-2 $tmp_file`;
+   }
 
    # diff the outputs.
    my $retval = system("diff $tmp_file $expected_output");
diff --git a/t/pt-log-player/play.t b/t/pt-log-player/play.t
index 54a0d85b..85c7feba 100644
--- a/t/pt-log-player/play.t
+++ b/t/pt-log-player/play.t
@@ -32,7 +32,6 @@ my $cmd = "$trunk/bin/pt-log-player --play $tmpdir -F /tmp/12345/my.sandbox.cnf
 
 diag(`rm -rf $tmpdir 2>/dev/null; mkdir $tmpdir`);
 
-
 # #############################################################################
 # Test that all session files gets assigned.
 # #############################################################################
@@ -42,7 +41,8 @@ for my $n ( 1..16 ) {
       no_diff(
          sub { pt_log_player::main(@args, '--threads', $n) },
          "t/pt-log-player/samples/assigned16-$n.txt",
-         trf => "sed -e 's!$trunk/t/pt-log-player/samples/16sessions/!!g'",
+         trf  => "sed -e 's!$trunk/t/pt-log-player/samples/16sessions/!!g'",
+         sort => '',
       ),
       "Assigned 16 sessions to $n threads"
    );
diff --git a/t/pt-log-player/samples/assigned16-1.txt b/t/pt-log-player/samples/assigned16-1.txt
index 01e5d29e..7fa0f4c8 100644
--- a/t/pt-log-player/samples/assigned16-1.txt
+++ b/t/pt-log-player/samples/assigned16-1.txt
@@ -1,17 +1,17 @@
 Found 16 session files.
-Process 0 plays s10
-Process 0 plays s03
-Process 0 plays s08
-Process 0 plays s06
-Process 0 plays s11
+Process 0 plays s01
 Process 0 plays s02
-Process 0 plays s15
-Process 0 plays s07
-Process 0 plays s13
+Process 0 plays s03
 Process 0 plays s04
 Process 0 plays s05
-Process 0 plays s12
+Process 0 plays s06
+Process 0 plays s07
+Process 0 plays s08
 Process 0 plays s09
+Process 0 plays s10
+Process 0 plays s11
+Process 0 plays s12
+Process 0 plays s13
 Process 0 plays s14
-Process 0 plays s01
+Process 0 plays s15
 Process 0 plays s16
diff --git a/t/pt-log-player/samples/assigned16-10.txt b/t/pt-log-player/samples/assigned16-10.txt
index b4fb5f68..b75f6dc6 100644
--- a/t/pt-log-player/samples/assigned16-10.txt
+++ b/t/pt-log-player/samples/assigned16-10.txt
@@ -1,17 +1,17 @@
 Found 16 session files.
-Process 0 plays s10
-Process 0 plays s05
-Process 1 plays s03
-Process 1 plays s12
-Process 2 plays s08
-Process 2 plays s09
-Process 3 plays s06
-Process 3 plays s14
-Process 4 plays s11
-Process 4 plays s01
-Process 5 plays s02
-Process 5 plays s16
-Process 6 plays s15
-Process 7 plays s07
-Process 8 plays s13
-Process 9 plays s04
+Process 0 plays s06
+Process 0 plays s16
+Process 1 plays s05
+Process 1 plays s15
+Process 2 plays s04
+Process 2 plays s14
+Process 3 plays s03
+Process 3 plays s13
+Process 4 plays s02
+Process 4 plays s12
+Process 5 plays s01
+Process 5 plays s11
+Process 6 plays s10
+Process 7 plays s09
+Process 8 plays s08
+Process 9 plays s07
diff --git a/t/pt-log-player/samples/assigned16-11.txt b/t/pt-log-player/samples/assigned16-11.txt
index 5d877cc8..f55d19e7 100644
--- a/t/pt-log-player/samples/assigned16-11.txt
+++ b/t/pt-log-player/samples/assigned16-11.txt
@@ -1,17 +1,17 @@
 Found 16 session files.
-Process 0 plays s10
-Process 0 plays s12
-Process 1 plays s03
-Process 1 plays s09
-Process 2 plays s08
+Process 0 plays s05
+Process 0 plays s16
+Process 1 plays s04
+Process 1 plays s15
+Process 10 plays s06
+Process 2 plays s03
 Process 2 plays s14
-Process 3 plays s06
-Process 3 plays s01
-Process 4 plays s11
-Process 4 plays s16
-Process 5 plays s02
-Process 6 plays s15
-Process 7 plays s07
-Process 8 plays s13
-Process 9 plays s04
-Process 10 plays s05
+Process 3 plays s02
+Process 3 plays s13
+Process 4 plays s01
+Process 4 plays s12
+Process 5 plays s11
+Process 6 plays s10
+Process 7 plays s09
+Process 8 plays s08
+Process 9 plays s07
diff --git a/t/pt-log-player/samples/assigned16-12.txt b/t/pt-log-player/samples/assigned16-12.txt
index 3a2fd29e..3f7519bc 100644
--- a/t/pt-log-player/samples/assigned16-12.txt
+++ b/t/pt-log-player/samples/assigned16-12.txt
@@ -1,17 +1,17 @@
 Found 16 session files.
-Process 0 plays s10
-Process 0 plays s09
+Process 0 plays s04
+Process 0 plays s16
 Process 1 plays s03
-Process 1 plays s14
-Process 2 plays s08
-Process 2 plays s01
-Process 3 plays s06
-Process 3 plays s16
-Process 4 plays s11
-Process 5 plays s02
-Process 6 plays s15
-Process 7 plays s07
-Process 8 plays s13
-Process 9 plays s04
-Process 10 plays s05
-Process 11 plays s12
+Process 1 plays s15
+Process 10 plays s06
+Process 11 plays s05
+Process 2 plays s02
+Process 2 plays s14
+Process 3 plays s01
+Process 3 plays s13
+Process 4 plays s12
+Process 5 plays s11
+Process 6 plays s10
+Process 7 plays s09
+Process 8 plays s08
+Process 9 plays s07
diff --git a/t/pt-log-player/samples/assigned16-13.txt b/t/pt-log-player/samples/assigned16-13.txt
index a84db528..bb139c51 100644
--- a/t/pt-log-player/samples/assigned16-13.txt
+++ b/t/pt-log-player/samples/assigned16-13.txt
@@ -1,17 +1,17 @@
 Found 16 session files.
-Process 0 plays s10
-Process 0 plays s14
-Process 1 plays s03
-Process 1 plays s01
-Process 2 plays s08
-Process 2 plays s16
-Process 3 plays s06
-Process 4 plays s11
-Process 5 plays s02
-Process 6 plays s15
-Process 7 plays s07
-Process 8 plays s13
-Process 9 plays s04
-Process 10 plays s05
-Process 11 plays s12
-Process 12 plays s09
+Process 0 plays s03
+Process 0 plays s16
+Process 1 plays s02
+Process 1 plays s15
+Process 10 plays s06
+Process 11 plays s05
+Process 12 plays s04
+Process 2 plays s01
+Process 2 plays s14
+Process 3 plays s13
+Process 4 plays s12
+Process 5 plays s11
+Process 6 plays s10
+Process 7 plays s09
+Process 8 plays s08
+Process 9 plays s07
diff --git a/t/pt-log-player/samples/assigned16-14.txt b/t/pt-log-player/samples/assigned16-14.txt
index b7fb210c..92600f40 100644
--- a/t/pt-log-player/samples/assigned16-14.txt
+++ b/t/pt-log-player/samples/assigned16-14.txt
@@ -1,17 +1,17 @@
 Found 16 session files.
-Process 0 plays s10
-Process 0 plays s01
-Process 1 plays s03
-Process 1 plays s16
-Process 2 plays s08
-Process 3 plays s06
-Process 4 plays s11
-Process 5 plays s02
-Process 6 plays s15
-Process 7 plays s07
-Process 8 plays s13
-Process 9 plays s04
-Process 10 plays s05
-Process 11 plays s12
-Process 12 plays s09
-Process 13 plays s14
+Process 0 plays s02
+Process 0 plays s16
+Process 1 plays s01
+Process 1 plays s15
+Process 10 plays s06
+Process 11 plays s05
+Process 12 plays s04
+Process 13 plays s03
+Process 2 plays s14
+Process 3 plays s13
+Process 4 plays s12
+Process 5 plays s11
+Process 6 plays s10
+Process 7 plays s09
+Process 8 plays s08
+Process 9 plays s07
diff --git a/t/pt-log-player/samples/assigned16-15.txt b/t/pt-log-player/samples/assigned16-15.txt
index 039d0b33..d2862a79 100644
--- a/t/pt-log-player/samples/assigned16-15.txt
+++ b/t/pt-log-player/samples/assigned16-15.txt
@@ -1,17 +1,17 @@
 Found 16 session files.
-Process 0 plays s10
+Process 0 plays s01
 Process 0 plays s16
-Process 1 plays s03
-Process 2 plays s08
-Process 3 plays s06
-Process 4 plays s11
-Process 5 plays s02
-Process 6 plays s15
-Process 7 plays s07
-Process 8 plays s13
-Process 9 plays s04
-Process 10 plays s05
-Process 11 plays s12
-Process 12 plays s09
-Process 13 plays s14
-Process 14 plays s01
+Process 1 plays s15
+Process 10 plays s06
+Process 11 plays s05
+Process 12 plays s04
+Process 13 plays s03
+Process 14 plays s02
+Process 2 plays s14
+Process 3 plays s13
+Process 4 plays s12
+Process 5 plays s11
+Process 6 plays s10
+Process 7 plays s09
+Process 8 plays s08
+Process 9 plays s07
diff --git a/t/pt-log-player/samples/assigned16-16.txt b/t/pt-log-player/samples/assigned16-16.txt
index ecc6b5ee..7edc05e8 100644
--- a/t/pt-log-player/samples/assigned16-16.txt
+++ b/t/pt-log-player/samples/assigned16-16.txt
@@ -1,17 +1,17 @@
 Found 16 session files.
-Process 0 plays s10
-Process 1 plays s03
-Process 2 plays s08
-Process 3 plays s06
-Process 4 plays s11
-Process 5 plays s02
-Process 6 plays s15
-Process 7 plays s07
-Process 8 plays s13
-Process 9 plays s04
-Process 10 plays s05
-Process 11 plays s12
-Process 12 plays s09
-Process 13 plays s14
-Process 14 plays s01
-Process 15 plays s16
+Process 0 plays s16
+Process 1 plays s15
+Process 10 plays s06
+Process 11 plays s05
+Process 12 plays s04
+Process 13 plays s03
+Process 14 plays s02
+Process 15 plays s01
+Process 2 plays s14
+Process 3 plays s13
+Process 4 plays s12
+Process 5 plays s11
+Process 6 plays s10
+Process 7 plays s09
+Process 8 plays s08
+Process 9 plays s07
diff --git a/t/pt-log-player/samples/assigned16-2.txt b/t/pt-log-player/samples/assigned16-2.txt
index 298ac418..e6fcc85e 100644
--- a/t/pt-log-player/samples/assigned16-2.txt
+++ b/t/pt-log-player/samples/assigned16-2.txt
@@ -1,17 +1,17 @@
 Found 16 session files.
-Process 0 plays s10
+Process 0 plays s02
+Process 0 plays s04
+Process 0 plays s06
 Process 0 plays s08
-Process 0 plays s11
-Process 0 plays s15
-Process 0 plays s13
-Process 0 plays s05
-Process 0 plays s09
-Process 0 plays s01
+Process 0 plays s10
+Process 0 plays s12
+Process 0 plays s14
+Process 0 plays s16
+Process 1 plays s01
 Process 1 plays s03
-Process 1 plays s06
-Process 1 plays s02
+Process 1 plays s05
 Process 1 plays s07
-Process 1 plays s04
-Process 1 plays s12
-Process 1 plays s14
-Process 1 plays s16
+Process 1 plays s09
+Process 1 plays s11
+Process 1 plays s13
+Process 1 plays s15
diff --git a/t/pt-log-player/samples/assigned16-3.txt b/t/pt-log-player/samples/assigned16-3.txt
index 79cc65dd..ed0ad5c0 100644
--- a/t/pt-log-player/samples/assigned16-3.txt
+++ b/t/pt-log-player/samples/assigned16-3.txt
@@ -1,17 +1,17 @@
 Found 16 session files.
-Process 0 plays s10
-Process 0 plays s06
-Process 0 plays s15
+Process 0 plays s01
 Process 0 plays s04
-Process 0 plays s09
+Process 0 plays s07
+Process 0 plays s10
+Process 0 plays s13
 Process 0 plays s16
 Process 1 plays s03
-Process 1 plays s11
-Process 1 plays s07
-Process 1 plays s05
-Process 1 plays s14
-Process 2 plays s08
+Process 1 plays s06
+Process 1 plays s09
+Process 1 plays s12
+Process 1 plays s15
 Process 2 plays s02
-Process 2 plays s13
-Process 2 plays s12
-Process 2 plays s01
+Process 2 plays s05
+Process 2 plays s08
+Process 2 plays s11
+Process 2 plays s14
diff --git a/t/pt-log-player/samples/assigned16-4.txt b/t/pt-log-player/samples/assigned16-4.txt
index 72b4fa34..bcd2d02d 100644
--- a/t/pt-log-player/samples/assigned16-4.txt
+++ b/t/pt-log-player/samples/assigned16-4.txt
@@ -1,17 +1,17 @@
 Found 16 session files.
-Process 0 plays s10
-Process 0 plays s11
-Process 0 plays s13
-Process 0 plays s09
+Process 0 plays s04
+Process 0 plays s08
+Process 0 plays s12
+Process 0 plays s16
 Process 1 plays s03
-Process 1 plays s02
-Process 1 plays s04
-Process 1 plays s14
-Process 2 plays s08
-Process 2 plays s15
-Process 2 plays s05
-Process 2 plays s01
-Process 3 plays s06
-Process 3 plays s07
-Process 3 plays s12
-Process 3 plays s16
+Process 1 plays s07
+Process 1 plays s11
+Process 1 plays s15
+Process 2 plays s02
+Process 2 plays s06
+Process 2 plays s10
+Process 2 plays s14
+Process 3 plays s01
+Process 3 plays s05
+Process 3 plays s09
+Process 3 plays s13
diff --git a/t/pt-log-player/samples/assigned16-5.txt b/t/pt-log-player/samples/assigned16-5.txt
index 0e15bbb4..6dd1cae5 100644
--- a/t/pt-log-player/samples/assigned16-5.txt
+++ b/t/pt-log-player/samples/assigned16-5.txt
@@ -1,17 +1,17 @@
 Found 16 session files.
-Process 0 plays s10
-Process 0 plays s02
-Process 0 plays s05
+Process 0 plays s01
+Process 0 plays s06
+Process 0 plays s11
 Process 0 plays s16
-Process 1 plays s03
+Process 1 plays s05
+Process 1 plays s10
 Process 1 plays s15
-Process 1 plays s12
-Process 2 plays s08
-Process 2 plays s07
+Process 2 plays s04
 Process 2 plays s09
-Process 3 plays s06
+Process 2 plays s14
+Process 3 plays s03
+Process 3 plays s08
 Process 3 plays s13
-Process 3 plays s14
-Process 4 plays s11
-Process 4 plays s04
-Process 4 plays s01
+Process 4 plays s02
+Process 4 plays s07
+Process 4 plays s12
diff --git a/t/pt-log-player/samples/assigned16-6.txt b/t/pt-log-player/samples/assigned16-6.txt
index 76eafcdf..238e04f0 100644
--- a/t/pt-log-player/samples/assigned16-6.txt
+++ b/t/pt-log-player/samples/assigned16-6.txt
@@ -1,17 +1,17 @@
 Found 16 session files.
+Process 0 plays s04
 Process 0 plays s10
-Process 0 plays s15
-Process 0 plays s09
+Process 0 plays s16
 Process 1 plays s03
-Process 1 plays s07
-Process 1 plays s14
+Process 1 plays s09
+Process 1 plays s15
+Process 2 plays s02
 Process 2 plays s08
-Process 2 plays s13
-Process 2 plays s01
-Process 3 plays s06
-Process 3 plays s04
-Process 3 plays s16
-Process 4 plays s11
-Process 4 plays s05
-Process 5 plays s02
-Process 5 plays s12
+Process 2 plays s14
+Process 3 plays s01
+Process 3 plays s07
+Process 3 plays s13
+Process 4 plays s06
+Process 4 plays s12
+Process 5 plays s05
+Process 5 plays s11
diff --git a/t/pt-log-player/samples/assigned16-7.txt b/t/pt-log-player/samples/assigned16-7.txt
index e441fc4a..85cd73c5 100644
--- a/t/pt-log-player/samples/assigned16-7.txt
+++ b/t/pt-log-player/samples/assigned16-7.txt
@@ -1,17 +1,17 @@
 Found 16 session files.
-Process 0 plays s10
-Process 0 plays s07
-Process 0 plays s01
-Process 1 plays s03
-Process 1 plays s13
-Process 1 plays s16
-Process 2 plays s08
-Process 2 plays s04
+Process 0 plays s02
+Process 0 plays s09
+Process 0 plays s16
+Process 1 plays s01
+Process 1 plays s08
+Process 1 plays s15
+Process 2 plays s07
+Process 2 plays s14
 Process 3 plays s06
-Process 3 plays s05
-Process 4 plays s11
+Process 3 plays s13
+Process 4 plays s05
 Process 4 plays s12
-Process 5 plays s02
-Process 5 plays s09
-Process 6 plays s15
-Process 6 plays s14
+Process 5 plays s04
+Process 5 plays s11
+Process 6 plays s03
+Process 6 plays s10
diff --git a/t/pt-log-player/samples/assigned16-8.txt b/t/pt-log-player/samples/assigned16-8.txt
index 2c972ee5..c784e427 100644
--- a/t/pt-log-player/samples/assigned16-8.txt
+++ b/t/pt-log-player/samples/assigned16-8.txt
@@ -1,17 +1,17 @@
 Found 16 session files.
-Process 0 plays s10
-Process 0 plays s13
-Process 1 plays s03
-Process 1 plays s04
-Process 2 plays s08
-Process 2 plays s05
-Process 3 plays s06
-Process 3 plays s12
-Process 4 plays s11
-Process 4 plays s09
-Process 5 plays s02
-Process 5 plays s14
-Process 6 plays s15
-Process 6 plays s01
-Process 7 plays s07
-Process 7 plays s16
+Process 0 plays s08
+Process 0 plays s16
+Process 1 plays s07
+Process 1 plays s15
+Process 2 plays s06
+Process 2 plays s14
+Process 3 plays s05
+Process 3 plays s13
+Process 4 plays s04
+Process 4 plays s12
+Process 5 plays s03
+Process 5 plays s11
+Process 6 plays s02
+Process 6 plays s10
+Process 7 plays s01
+Process 7 plays s09
diff --git a/t/pt-log-player/samples/assigned16-9.txt b/t/pt-log-player/samples/assigned16-9.txt
index cf4909e0..7825166c 100644
--- a/t/pt-log-player/samples/assigned16-9.txt
+++ b/t/pt-log-player/samples/assigned16-9.txt
@@ -1,17 +1,17 @@
 Found 16 session files.
-Process 0 plays s10
-Process 0 plays s04
-Process 1 plays s03
-Process 1 plays s05
-Process 2 plays s08
-Process 2 plays s12
-Process 3 plays s06
-Process 3 plays s09
-Process 4 plays s11
-Process 4 plays s14
+Process 0 plays s07
+Process 0 plays s16
+Process 1 plays s06
+Process 1 plays s15
+Process 2 plays s05
+Process 2 plays s14
+Process 3 plays s04
+Process 3 plays s13
+Process 4 plays s03
+Process 4 plays s12
 Process 5 plays s02
-Process 5 plays s01
-Process 6 plays s15
-Process 6 plays s16
-Process 7 plays s07
-Process 8 plays s13
+Process 5 plays s11
+Process 6 plays s01
+Process 6 plays s10
+Process 7 plays s09
+Process 8 plays s08