How to interpret Papi output

Question

I have collected data of Number of L2 cache misses using PAPI. I had run an MPI application with 4 threads (mpirun -np 4) and each thread reads the cache misses in L2. Each thread outputs data for every timestamp. eg:

Timestamp              data
xxx530     thread# 0   2136
xxx531     thread# 0   3217
..           .          .
.            .          . 
.            .          .
.            .          .
xxx550      thread# 0   412334255

xxx530      thread #1    2456
xxx531      thread#1     4243
xxx532      thread #1    4567 
and so on

Now my qstn , is whether i shud add all the cache miss values at time stamp xxx530 for thread 0,1, 2 and 3 OR shud i take the max-value for thrreda0,1,2,3 for timestamp xxx530 ?