Linq to Sql, InsertAllOnSubmit

using linq to sql, I need to insert two records on each iteration through a loop (perhaps 2000 times)

I know I can use this technique
    table_sql tbl1 = new table_sql();
    // set the column values for table_sql
    dc.table_sqls.InsertOnSubmit(tbl1);

    table_sql tbl2 = new table_sql();
    // set the column values for table_sql
    dc.table_sqls.InsertOnSubmit(tbl2);

    Then do dc.SubmitChanges from the calling loop (because other things happen in the loop, too)

I assume, however, that it would be better to use an InsertAllOnSubmit for this in that it would cut the number of connection open/close operations in half.

How do I use InsertAllOnSubmit for this?