Scale sequence length in CP tests to avoid tiny sizes.

Signed-off-by: Michael Goldfarb <[email protected]>

tests/jax/test_distributed_fused_attn.py

@@ -341,8 +341,9 @@ def ref_func(query, kv, mask):
 @pytest.mark.parametrize(
     "data_shape",
     [
-        pytest.param([2, 512, 12, 128], id="2-512-12-128"),
-        pytest.param([4, 1024, 16, 64], id="4-1024-16-64"),
+        # Sequence lengths will be scaled by CP so that we don't run with tiny sizes.
+        pytest.param([2, 128, 12, 128], id="2-128xCP-12-128"),
+        pytest.param([4, 256, 16, 64], id="4-256xCP-16-64"),
     ],
 )
 @pytest.mark.parametrize("kv_groups", [1, 4, 8, 12, 16])
@@ -423,6 +424,12 @@ def impl_test_contex_parallel_attn(
         qkv_format = get_qkv_format(qkv_layout)
 
         batch, seqlen, num_head, hidden = data_shape
+
+        # Scale the sequence length by 2*CP so its never too small as we scale up test.
+        # 2*CP is used since we split into two CP groups for load balancing.
+        seqlen = seqlen * cp_size * 2
+        data_shape = batch, seqlen, num_head, hidden
+
         num_kv_heads = num_head // kv_groups
         scaling_factor = 1.0 / np.sqrt(num_head)