perf intel-pt: Fix last_ip usage
commit ee14ac0e upstream. Intel PT uses IP compression based on the last IP. For decoding purposes, 'last IP' is considered to be reset to zero whenever there is a synchronization packet (PSB). The decoder wasn't doing that, and was treating the zero value to mean that there was no last IP, whereas compression can be done against the zero value. Fix by setting last_ip to zero when a PSB is received and keep track of have_last_ip. Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Cc: Andi Kleen <ak@linux.intel.com> Link: http://lkml.kernel.org/r/1495786658-18063-6-git-send-email-adrian.hunter@intel.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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