+# Perf event counters are only supported on x86 so far.
+AC_MSG_CHECKING([UST support for architecture perf event counters])
+case $host_cpu in
+changequote(,)dnl
+ i[3456]86)
+changequote([,])dnl
+ UST_SUPPORT_FOR_ARCH_PERF_EVENT_COUNTERS=yes;;
+ x86_64) UST_SUPPORT_FOR_ARCH_PERF_EVENT_COUNTERS=yes;;
+ amd64) UST_SUPPORT_FOR_ARCH_PERF_EVENT_COUNTERS=yes;;
+ *) UST_SUPPORT_FOR_ARCH_PERF_EVENT_COUNTERS=no;;
+esac
+AC_MSG_RESULT([$UST_SUPPORT_FOR_ARCH_PERF_EVENT_COUNTERS])
+
+AM_CONDITIONAL([HAVE_PERF_EVENT], [test "x$have_perf_event" = "xyes" -a "x$UST_SUPPORT_FOR_ARCH_PERF_EVENT_COUNTERS" = "xyes"])
+
+if test "x$have_perf_event" = "xyes" -a "x$UST_SUPPORT_FOR_ARCH_PERF_EVENT_COUNTERS" = "xyes"; then