On 09/10/2013 07:36 AM, Michael Ellerman wrote: > On Fri, 2013-08-30 at 09:54 +0530, Anshuman Khandual wrote: >> This patchset is the re-spin of the original branch stack sampling >> patchset which introduced new PERF_SAMPLE_BRANCH_COND filter. This patchset >> also enables SW based branch filtering support for PPC64 platforms which have >> branch stack sampling support. With this new enablement, the branch filter >> support >> for PPC64 platforms have been extended to include all these combinations >> discussed >> below with a sample test application program. > > ... > >> Mixed filters >> ------------- >> (6) perf record -e branch-misses:u -j any_call,any_ret ./cprog >> Error: >> The perf.data file has no samples! >> >> NOTE: As expected. The HW filters all the branches which are calls and SW >> tries to find return >> branches in that given set. Both the filters are mutually exclussive, so >> obviously no samples >> found in the end profile. > > The semantics of multiple filters is not clear to me. It could be an OR, > or an AND. You have implemented AND, does that match existing behaviour > on x86 for example?
I believe it does match. X86 code drops the branch records (originally captured in the LBR) while applying the SW filters. Regards Anshuman -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
