Date: Tue, 12 Jan 1999 21:41:32 -0600 (CST) From: Mohit Aron <aron@cs.rice.edu> To: freebsd-hackers@FreeBSD.ORG Subject: Performance counters on Pentium Pro's Message-ID: <199901130341.VAA14056@cs.rice.edu>
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Hi, it seems that the driver for reading Pentium Pro performance counters in FreeBSD-2.2.6 doesn't work (it works with a Pentium though). I've already configured and compiled my kernel with support for the driver and I'm trying to read the data cache misses. Below are some sample commands with the example program provided in /usr/share/examples/perfmon. # ./perfmon -o -u -e -l 2 -s 1 72 1: 3298535393077 2: 3298535358033 total: 6597070751110.000000 mean: 3298535375555.000000 clocks (at 299-MHz): 603885293 # ./perfmon -o -u -e -l 2 -s 1 0 1: 3298534883328 2: 3298534883328 total: 6597069766656.000000 mean: 3298534883328.000000 clocks (at 299-MHz): 603491159 # ./perfmon -o -u -l 2 -s 1 72 1: 3298535418313 2: 3298535807953 total: 6597071226266.000000 mean: 3298535613133.000000 clocks (at 299-MHz): 603927055 Notice that using event 72 (or 0x48 as suggested in /usr/include/machine/perfmon.h for reading data cache misses) seems to throw out a large number. This number seems to remain relatively unchanged when I use other events (the 2nd example above uses 0). In fact the output of the program even seems to be similar when I don't use the '-e' flag which is supposed to count the number of events rather than their duration. I've also contacted the person who wrote the code (Garrett Wollman) and he agrees that he had some questionable results with Pentium Pro in the past but never tracked them down. Does someone have a fix for this problem ? - Mohit To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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