From one of the article, I get:

database sysmaster;
select
dbsname,
tabname,
bufreads,
pagreads
deadlks
from sysptprof
order by deadlks desc;

and the output (deadlks) is negative value. What does it mean?

From one of the article, I get:
database sysmaster;
select
dbsname,
tabname,
bufreads,
pagreads
deadlks
from sysptprof
order by deadlks desc;

and the output (bufreads) is negative value. What does it mean?

A negative value normally means an overflow.
bufreads/bufwrites can reach very high values a heavy
loaded system.

So you need to make sure that you reset the statistics
at regular intervals (onstat -z) in order to avoid
any overflows.

However for deadlocks there should not be an overflow.
This makes no sense. I could not imagine that you have
so much deadlocks in your system. I would consider
this as an IFMX bug and call IFMX tech support.