I find the problem is in my outer procedure, because it has no sleep there, 
and I change it calling pg_sleep:
-- Function: "TestProcOuter"()
-- DROP FUNCTION "TestProcOuter"();
CREATE OR REPLACE FUNCTION "TestProcOuter"() RETURNS integer AS
$BODY$
DECLARE       Loops int4 := 1;
BEGIN       LOOP               RAISE NOTICE 'TestProcOuter: % loop', Loops;               IF 0 = "TestProcInner"() THEN
                     EXIT; -- LOOP               END IF;               Loops = Loops + 1;               PERFORM
pg_sleep(4);      END LOOP;
 
       RETURN 0;
END;
$BODY$ LANGUAGE 'plpgsql' VOLATILE;
ALTER FUNCTION "TestProcOuter"() OWNER TO postgres;
With this change, I found the first session succeeds, the CPU is not rised 
anymore, but the second session doesn't succeed even after the first one 
finish successfully.
It fails forever.
Why ? What have I make to succeed ?
TIA,
Sabin