hwpmc overflow

Anton Yuzhaninov citrin at citrin.ru
Wed Sep 28 10:06:14 UTC 2011


On Wed, 28 Sep 2011 01:44:42, George Neville-Neil wrote:
GNN> If you count them individually do you still get the overflows?  That is, if you run
GNN> the same workload but only count instructions, then run it again with the next counter,
GNN> etc.  I am wondering if something is wrong because of the number of things you're trying
GNN> to count at the same time.

for one counter problem the same.

This test on other hardware:
CPU: Intel(R) Xeon(R) CPU E5335 @ 2.00GHz (2004.98-MHz K8-class CPU)
hwpmc: TSC/1/64/0x20<REA> IAP/2/40/0x3ff<INT,USR,SYS,EDG,THR,REA,WRI,INV,QUA,PRC> IAF/3/40/0x61<INT,REA,WRI>

Counter for DTLB_MISSES.ANY should overflow at 2^40 - 1
But again I see overflow near 2^31

# pmcstat -C -w1 -d -p DTLB_MISSES.ANY -o pmc.log -t 10924

from log:
   2022802283
   2041525661
   2061836744
   2083646634
   2103665903
   2123998093
   2142902046
1097377998076
1097397893694
1097424659734
1097446393399
1097469768564
1097495460707
1097519426191

-- 
 Anton Yuzhaninov



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