Required dependencies for libbpf-tools?

Following up on Brendan Gregg's excellent http://www.brendangregg.com/blog/2020-11-04/bpf-co-re-btf-libbpf.html I looked into packaging the `libbpf-tools` binaries (`biolatency`, `biopattern`, `biosnoop`, `biostacks`, `bitesize`, `cpudist`, `drsnoop`, `execsnoop`, `filelife`, `hardirqs`, `llcstat`, `numamove`, `opensnoop`, `readahead`, `runqlat`, `runqlen`, `runqslower`, `softirqs`, `syscount`, `tcpconnect`, `tcpconnlat`, `vfsstat` + `xfsslower`), to be able to use them on systems without having to install lots of additional packages.

I did my packaging work on current Debian testing/bullseye, see https://gist.github.com/mika/e55ab72659bda90d8fecbbb42830d250

Most of the binaries work as intended, though `readahead`, `xfsslower` + `llcstat` are failing for me (both on the system where I built the binaries as well as on another Debian/bullseye system with just the compiled binaries and an according kernel with `CONFIG_DEBUG_INFO_BTF` enabled):

```
% sudo readahead
libbpf: failed to find kernel BTF type ID of '__do_page_cache_readahead': -3
libbpf: failed to load object 'readahead_bpf'
libbpf: failed to load BPF skeleton 'readahead_bpf': -3
failed to open and/or load BPF ojbect

% sudo xfsslower
libbpf: kprobe perf_event_open() failed: No such file or directory
libbpf: prog 'xfs_file_read_iter': failed to create kprobe 'xfs_file_read_iter' perf event: No such file or directory
libbpf: failed to auto-attach program 'xfs_file_read_iter': -2
failed to attach BPF programs

% sudo llcstat
failed to init perf sampling: No such file or directory
% sudo strace -f -s500 llcstat 2>&1 | tail
munmap(0x7f17e10f2000, 360448) = 0
perf_event_open({type=PERF_TYPE_HARDWARE, size=0 /* PERF_ATTR_SIZE_??? */, config=PERF_COUNT_HW_CACHE_MISSES, ...}, -1, 0, -1, 0) = -1 ENOENT (No such file or directory)
write(2, "failed to init perf sampling: No such file or directory\n", 56failed to init perf sampling: No such file or directory) = 56
[...]
```

Any hints what's missing here? (I'd like to ensure the BTF support is as good as possible on Debian/bullseye, being the upcoming stable release of Debian.)

Thanks!

Start with the linked Debian packaging notes and reproduce readahead, xfsslower, and llcstat on Debian bullseye with CONFIG_DEBUG_INFO_BTF enabled. Trace the failing libbpf and perf_event_open paths, then document the missing runtime or kernel dependencies so the three tools work with the packaged binaries.

Written by the indexing model from the issue text.