diff --git a/umi/sumi/tests/conftest.py b/umi/sumi/tests/conftest.py
index bc56321..4591f1c 100644
--- a/umi/sumi/tests/conftest.py
+++ b/umi/sumi/tests/conftest.py
@@ -68,3 +68,19 @@ def sumi_dut(build_dir, request):
     yield dut
 
     dut.terminate()
+
+
+def pytest_addoption(parser):
+    parser.addoption("--seed", type=int, action="store", help="Provide a fixed seed")
+
+
+@pytest.fixture
+def random_seed(request):
+    fixed_seed = request.config.getoption("--seed")
+    if fixed_seed is not None:
+        test_seed = fixed_seed
+    else:
+        test_seed = os.getpid()
+    print(f'Random seed used: {test_seed}')
+    yield test_seed
+    print(f'Random seed used: {test_seed}')
diff --git a/umi/sumi/tests/test_crossbar.py b/umi/sumi/tests/test_crossbar.py
index 4d74cd6..d8b5a1b 100755
--- a/umi/sumi/tests/test_crossbar.py
+++ b/umi/sumi/tests/test_crossbar.py
@@ -6,15 +6,12 @@
 import pytest
 import multiprocessing
 import random
-import numpy as np
 from switchboard import UmiTxRx, random_umi_packet, delete_queue
 
 
-def umi_send(x, n, ports):
-    import os
+def umi_send(x, n, ports, seed):
 
-    random.seed(os.getpid())
-    np.random.seed(os.getpid())
+    random.seed(seed)
 
     umi = UmiTxRx(f'client2rtl_{x}.q', '')
     tee = UmiTxRx(f'tee_{x}.q', '')
@@ -32,7 +29,7 @@ def umi_send(x, n, ports):
 
 
 @pytest.mark.skip(reason="Crossbar asserts output valid even when in reset")
-def test_crossbar(sumi_dut, sb_umi_valid_mode, sb_umi_ready_mode):
+def test_crossbar(sumi_dut, random_seed, sb_umi_valid_mode, sb_umi_ready_mode):
     n = 100
     ports = 4
     for x in range(ports):
@@ -59,7 +56,7 @@ def test_crossbar(sumi_dut, sb_umi_valid_mode, sb_umi_ready_mode):
 
     procs = []
     for x in range(ports):
-        procs.append(multiprocessing.Process(target=umi_send, args=(x, n, ports,)))
+        procs.append(multiprocessing.Process(target=umi_send, args=(x, n, ports, (random_seed+x),)))
 
     for proc in procs:
         proc.start()
diff --git a/umi/sumi/tests/test_fifo.py b/umi/sumi/tests/test_fifo.py
index e86e74b..29d8cb9 100755
--- a/umi/sumi/tests/test_fifo.py
+++ b/umi/sumi/tests/test_fifo.py
@@ -9,7 +9,10 @@
 from switchboard import UmiTxRx
 
 
-def test_fifo(sumi_dut, sb_umi_valid_mode, sb_umi_ready_mode):
+def test_fifo(sumi_dut, random_seed, sb_umi_valid_mode, sb_umi_ready_mode):
+
+    random.seed(random_seed)
+    np.random.seed(random_seed)
 
     # launch the simulation
     sumi_dut.simulate(plusargs=[('valid_mode', sb_umi_valid_mode), ('ready_mode', sb_umi_ready_mode)])
diff --git a/umi/sumi/tests/test_fifo_flex.py b/umi/sumi/tests/test_fifo_flex.py
index 53714ca..7415cb1 100755
--- a/umi/sumi/tests/test_fifo_flex.py
+++ b/umi/sumi/tests/test_fifo_flex.py
@@ -9,7 +9,10 @@
 from switchboard import UmiTxRx
 
 
-def test_fifo_flex(sumi_dut, sb_umi_valid_mode, sb_umi_ready_mode):
+def test_fifo_flex(sumi_dut, random_seed, sb_umi_valid_mode, sb_umi_ready_mode):
+
+    random.seed(random_seed)
+    np.random.seed(random_seed)
 
     # launch the simulation
     sumi_dut.simulate(plusargs=[('valid_mode', sb_umi_valid_mode), ('ready_mode', sb_umi_ready_mode)])
diff --git a/umi/sumi/tests/test_mem_agent.py b/umi/sumi/tests/test_mem_agent.py
index f418c3e..69f1430 100755
--- a/umi/sumi/tests/test_mem_agent.py
+++ b/umi/sumi/tests/test_mem_agent.py
@@ -52,7 +52,9 @@ def apply_atomic(origdata, atomicdata, operation, maxrange):
     return tempval
 
 
-def test_mem_agent(sumi_dut, sb_umi_valid_mode, sb_umi_ready_mode):
+def test_mem_agent(sumi_dut, random_seed, sb_umi_valid_mode, sb_umi_ready_mode):
+
+    np.random.seed(random_seed)
 
     # launch the simulation
     sumi_dut.simulate(plusargs=[('valid_mode', sb_umi_valid_mode), ('ready_mode', sb_umi_ready_mode)])