Messages in this thread | | | Date | Fri, 12 Jun 2009 16:15:26 +0800 | From | Yong Wang <> | Subject | Re: [PATCH -tip] perf_counter/x86: Correct some event and umask values for Intel processors |
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On Wed, Jun 10, 2009 at 12:42:42PM +0200, Ingo Molnar wrote: > > * Yong Wang <yong.y.wang@linux.intel.com> wrote: > > > On Tue, Jun 09, 2009 at 04:16:21PM +0200, Ingo Molnar wrote: > > > > > > * Yong Wang <yong.y.wang@linux.intel.com> wrote: > > > > > > > Correct some event and UMASK values according to Intel SDM. > > > > > > Very nice, thanks! > > > > > > were you able to test the Atom ones by any chance? > > > > > > > You bet I was as I'm working on Moblin ;-) [...] > > Heh :-) > > > [...] However, some work while some do not. I'll take a look at > > the problematic ones. With the previous event and umask values, > > the pmc does not count at all for some events, like l1d-write-ops. > > Interesting. I had a good look at the Atom details in the docs but > couldnt find anything suspicious. There's various umask level > extensions (sometimes cflags level ones) like whether to measure the > core or the thread, but the defaults (zero) seem to have OK > semantics for most of the events. > > Btw., when mapping out event tables there's one little trick i used > to 'scan' an event, using 'perf stat' and raw event numbers: > > for ((i=0;i<256;i++)); do \ > perf stat -e $(printf "r%02x%02x\n" $i 0xc0) true 2>&1 | \ > grep -w raw | grep -vw 0; \ > done > > This scans all 256 umask values for the main event code of 0xc0, and > displays the umask values where the counter show some activity. > > ( if it's some rare event then you might want to run something else > that excercises that event, not /bin/true. ) >
Just took a look at the problematics ones and found that the fixed function PMCs do not work on current Atom processors. I tested on 3 Atom netbooks and the results are the same. Just sent a quirk patch for that.
-Yong
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