3.13.0-123.172) is not available, but a newer one is (3.13.0-166.216). We redirected you there.
/usr/lib/linux-tools/3.13.0-55-lowlatency/perf is in linux-tools-3.13.0-55-lowlatency 3.13.0-55.94.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/linux-tools/3.13.0-55-lowlatency/../../linux-tools-3.13.0-55/perf