It looks like you picked up some "think" time. With only the information provided, I am inclined to think that the 120.46 attributed to SQL Net Message From Client is due more to a scoping problem then the actual truncate. Ensure there is no delay between targeted action and the start and stop of the trace.
We see lot of waits in the database on "SQL*Net message from client" and following is one of the sample query with wait events from tkprof, what can be the possible reason for long wait for this event for truncate command? TRUNCATE TABLE tab1 call count cpu elapsed disk query current rows ------- ------ -------- ---------- ---------- ---------- ---------- ---------- Parse 1 0.00 0.00 0 0 0 0 Execute 1 0.27 0.36 18 2 122 0 Fetch 0 0.00 0.00 0 0 0 0 ------- ------ -------- ---------- ---------- ---------- ---------- ---------- total 2 0.27 0.36 18 2 122 0 Misses in library cache during parse: 1 Optimizer mode: ALL_ROWS Parsing user id: 172 Elapsed times include waiting on following events: Event waited on Times Max. Wait Total Waited ---------------------------------------- Waited ---------- ------------ db file sequential read 18 0.00 0.00 enq: RO - fast object reuse 6 0.01 0.02 local write wait 11 0.00 0.05 log file sync 1 0.00 0.00 SQL*Net message to client 1 0.00 0.00 SQL*Net message from client 1 120.46 120.46