On Sun, Mar 29, 2020 at 4:35 PM Eric Sage [off-list ref] wrote:

At Facebook we use tail calls to jump between our firewall filters and
our L4LB. This is a program I wrote to estimate per program performance
by swapping out the entries in the program array with interceptors that
take measurements and then jump to the original entries.

I found the sample programs to be invaluable in understanding how to use
the libbpf API (as well as the test env from the xdp-tutorial repo for
testing), and want to return the favor. I am currently working on
my next iteration that uses fentry/fexit to be less invasive,
but I thought it was an interesting PoC of what you can do with program
arrays.

v4:
- rebase
v3:
- Fixed typos in xdp_stat_kern.c
- Switch to using key_size, value_size for prog arrays

Signed-off-by: Eric Sage <redacted>
Acked-by: Andrii Nakryiko <redacted>
---
 samples/bpf/Makefile          |   3 +
 samples/bpf/xdp_stat          | Bin 0 -> 200488 bytes

Add xdp_stat to .gitignore?

 samples/bpf/xdp_stat_common.h |  28 ++
 samples/bpf/xdp_stat_kern.c   | 192 +++++++++
 samples/bpf/xdp_stat_user.c   | 748 ++++++++++++++++++++++++++++++++++
 5 files changed, 971 insertions(+)
 create mode 100755 samples/bpf/xdp_stat
 create mode 100644 samples/bpf/xdp_stat_common.h
 create mode 100644 samples/bpf/xdp_stat_kern.c
 create mode 100644 samples/bpf/xdp_stat_user.c