linux/samples/bpf
Alexei Starovoitov 95ff141e52 samples/bpf: add map_lookup microbenchmark
$ map_perf_test 128
speed of HASH bpf_map_lookup_elem() in lookups per second
	w/o JIT		w/JIT
before	46M		58M
after	42M		74M

perf report
before:
    54.23%  map_perf_test  [kernel.kallsyms]  [k] __htab_map_lookup_elem
    14.24%  map_perf_test  [kernel.kallsyms]  [k] lookup_elem_raw
     8.84%  map_perf_test  [kernel.kallsyms]  [k] htab_map_lookup_elem
     5.93%  map_perf_test  [kernel.kallsyms]  [k] bpf_map_lookup_elem
     2.30%  map_perf_test  [kernel.kallsyms]  [k] bpf_prog_da4fc6a3f41761a2
     1.49%  map_perf_test  [kernel.kallsyms]  [k] kprobe_ftrace_handler

after:
    60.03%  map_perf_test  [kernel.kallsyms]  [k] __htab_map_lookup_elem
    18.07%  map_perf_test  [kernel.kallsyms]  [k] lookup_elem_raw
     2.91%  map_perf_test  [kernel.kallsyms]  [k] bpf_prog_da4fc6a3f41761a2
     1.94%  map_perf_test  [kernel.kallsyms]  [k] _einittext
     1.90%  map_perf_test  [kernel.kallsyms]  [k] __audit_syscall_exit
     1.72%  map_perf_test  [kernel.kallsyms]  [k] kprobe_ftrace_handler

Notice that bpf_map_lookup_elem() and htab_map_lookup_elem() are trivial
functions, yet they take sizeable amount of cpu time.
htab_map_gen_lookup() removes bpf_map_lookup_elem() and converts
htab_map_lookup_elem() into three BPF insns which causing cpu time
for bpf_prog_da4fc6a3f41761a2() slightly increase.

$ map_perf_test 256
speed of ARRAY bpf_map_lookup_elem() in lookups per second
	w/o JIT		w/JIT
before	97M		174M
after	64M		280M

before:
    37.33%  map_perf_test  [kernel.kallsyms]  [k] array_map_lookup_elem
    13.95%  map_perf_test  [kernel.kallsyms]  [k] bpf_map_lookup_elem
     6.54%  map_perf_test  [kernel.kallsyms]  [k] bpf_prog_da4fc6a3f41761a2
     4.57%  map_perf_test  [kernel.kallsyms]  [k] kprobe_ftrace_handler

after:
    32.86%  map_perf_test  [kernel.kallsyms]  [k] bpf_prog_da4fc6a3f41761a2
     6.54%  map_perf_test  [kernel.kallsyms]  [k] kprobe_ftrace_handler

array_map_gen_lookup() removes calls to array_map_lookup_elem()
and bpf_map_lookup_elem() and replaces them with 7 bpf insns.

The performance without JIT is slower, since executing extra insns
in the interpreter is slower than running native C code,
but with JIT the performance gains are obvious,
since native C->x86 code is replaced with fewer bpf->x86 instructions.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-03-16 20:44:12 -07:00
..
Makefile Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-12-23 16:49:12 -08:00
README.rst samples/bpf: Switch over to libbpf 2016-12-20 12:00:38 -03:00
bpf_helpers.h bpf: xdp: Add XDP example for head adjustment 2016-12-08 14:25:13 -05:00
bpf_load.c samples/bpf: Reset global variables 2017-02-13 17:22:53 -03:00
bpf_load.h samples/bpf: Make samples more libbpf-centric 2016-12-15 16:25:47 -03:00
cgroup_helpers.c samples, bpf: Refactor test_current_task_under_cgroup - separate out helpers 2016-12-03 16:07:11 -05:00
cgroup_helpers.h samples, bpf: Refactor test_current_task_under_cgroup - separate out helpers 2016-12-03 16:07:11 -05:00
fds_example.c samples/bpf: Move open_raw_sock to separate header 2016-12-20 12:00:40 -03:00
lathist_kern.c bpf: BPF based latency tracing 2015-06-23 06:09:58 -07:00
lathist_user.c samples/bpf: Make samples more libbpf-centric 2016-12-15 16:25:47 -03:00
libbpf.h samples/bpf: Move open_raw_sock to separate header 2016-12-20 12:00:40 -03:00
lwt_len_hist.sh bpf: Add tests and samples for LWT-BPF 2016-12-02 10:52:00 -05:00
lwt_len_hist_kern.c bpf: Add tests and samples for LWT-BPF 2016-12-02 10:52:00 -05:00
lwt_len_hist_user.c samples/bpf: Make samples more libbpf-centric 2016-12-15 16:25:47 -03:00
map_perf_test_kern.c samples/bpf: add map_lookup microbenchmark 2017-03-16 20:44:12 -07:00
map_perf_test_user.c samples/bpf: add map_lookup microbenchmark 2017-03-16 20:44:12 -07:00
offwaketime_kern.c bpf, samples: don't zero data when not needed 2016-04-14 21:40:42 -04:00
offwaketime_user.c samples/bpf: Make samples more libbpf-centric 2016-12-15 16:25:47 -03:00
parse_ldabs.c bpf: fix samples to add fake KBUILD_MODNAME 2016-10-29 14:46:12 -04:00
parse_simple.c bpf: fix samples to add fake KBUILD_MODNAME 2016-10-29 14:46:12 -04:00
parse_varlen.c bpf: fix samples to add fake KBUILD_MODNAME 2016-10-29 14:46:12 -04:00
sampleip_kern.c bpf/samples: Fix PT_REGS_IP on s390x and use it 2016-11-28 16:26:46 -05:00
sampleip_user.c samples/bpf: Remove perf_event_open() declaration 2016-12-20 12:00:40 -03:00
sock_example.c samples/bpf: Move open_raw_sock to separate header 2016-12-20 12:00:40 -03:00
sock_example.h samples/bpf sock_example: Avoid getting ethhdr from two includes 2016-12-27 21:49:17 -03:00
sock_flags_kern.c samples/bpf: add userspace example for prohibiting sockets 2016-12-02 13:46:09 -05:00
sockex1_kern.c samples: bpf: add skb->field examples and tests 2015-03-15 22:02:28 -04:00
sockex1_user.c samples/bpf: Move open_raw_sock to separate header 2016-12-20 12:00:40 -03:00
sockex2_kern.c samples/bpf: fix sockex2 example 2016-11-24 16:04:52 -05:00
sockex2_user.c samples/bpf: Move open_raw_sock to separate header 2016-12-20 12:00:40 -03:00
sockex3_kern.c bpf samples: fix compiler errors with sockex2 and sockex3 2016-09-27 03:48:58 -04:00
sockex3_user.c samples/bpf: Move open_raw_sock to separate header 2016-12-20 12:00:40 -03:00
spintest_kern.c samples/bpf: Enable powerpc support 2016-04-06 16:01:29 -04:00
spintest_user.c samples/bpf: Make samples more libbpf-centric 2016-12-15 16:25:47 -03:00
tc_l2_redirect.sh bpf: Add test for bpf_redirect to ipip/ip6tnl 2016-11-12 23:38:07 -05:00
tc_l2_redirect_kern.c bpf: fix samples xdp_tx_iptunnel and tc_l2_redirect with fake KBUILD_MODNAME 2017-01-20 12:04:07 -05:00
tc_l2_redirect_user.c samples/bpf: Make samples more libbpf-centric 2016-12-15 16:25:47 -03:00
tcbpf1_kern.c bpf: fix samples to add fake KBUILD_MODNAME 2016-10-29 14:46:12 -04:00
tcbpf2_kern.c bpf: fix samples to add fake KBUILD_MODNAME 2016-10-29 14:46:12 -04:00
test_cgrp2_array_pin.c samples/bpf: Make samples more libbpf-centric 2016-12-15 16:25:47 -03:00
test_cgrp2_attach.c bpf: introduce BPF_F_ALLOW_OVERRIDE flag 2017-02-12 21:52:19 -05:00
test_cgrp2_attach2.c bpf: introduce BPF_F_ALLOW_OVERRIDE flag 2017-02-12 21:52:19 -05:00
test_cgrp2_sock.c bpf: introduce BPF_F_ALLOW_OVERRIDE flag 2017-02-12 21:52:19 -05:00
test_cgrp2_sock.sh samples: bpf: add userspace example for modifying sk_bound_dev_if 2016-12-02 13:46:08 -05:00
test_cgrp2_sock2.c bpf: introduce BPF_F_ALLOW_OVERRIDE flag 2017-02-12 21:52:19 -05:00
test_cgrp2_sock2.sh samples/bpf: add userspace example for prohibiting sockets 2016-12-02 13:46:09 -05:00
test_cgrp2_tc.sh cgroup: bpf: Add an example to do cgroup checking in BPF 2016-07-01 16:32:13 -04:00
test_cgrp2_tc_kern.c bpf: fix samples to add fake KBUILD_MODNAME 2016-10-29 14:46:12 -04:00
test_cls_bpf.sh samples/bpf: add 'pointer to packet' tests 2016-05-06 16:01:54 -04:00
test_current_task_under_cgroup_kern.c samples/bpf: Add test_current_task_under_cgroup test 2016-08-12 21:49:42 -07:00
test_current_task_under_cgroup_user.c samples/bpf: Make samples more libbpf-centric 2016-12-15 16:25:47 -03:00
test_ipip.sh samples/bpf: add comprehensive ipip, ipip6, ip6ip6 test 2016-09-17 10:13:07 -04:00
test_lru_dist.c samples/bpf: Make samples more libbpf-centric 2016-12-15 16:25:47 -03:00
test_lwt_bpf.c bpf: Add tests and samples for LWT-BPF 2016-12-02 10:52:00 -05:00
test_lwt_bpf.sh bpf: Add tests and samples for LWT-BPF 2016-12-02 10:52:00 -05:00
test_overhead_kprobe_kern.c samples/bpf: add tracepoint vs kprobe performance tests 2016-04-07 21:04:27 -04:00
test_overhead_tp_kern.c samples/bpf: add tracepoint vs kprobe performance tests 2016-04-07 21:04:27 -04:00
test_overhead_user.c samples/bpf: add tracepoint vs kprobe performance tests 2016-04-07 21:04:27 -04:00
test_probe_write_user_kern.c samples/bpf: Add test/example of using bpf_probe_write_user bpf helper 2016-07-25 18:07:48 -07:00
test_probe_write_user_user.c samples/bpf: Make samples more libbpf-centric 2016-12-15 16:25:47 -03:00
test_tunnel_bpf.sh samples/bpf: extend test_tunnel_bpf.sh with IPIP test 2016-09-17 10:13:07 -04:00
trace_event_kern.c bpf/samples: Fix PT_REGS_IP on s390x and use it 2016-11-28 16:26:46 -05:00
trace_event_user.c samples/bpf: Remove perf_event_open() declaration 2016-12-20 12:00:40 -03:00
trace_output_kern.c samples/bpf: fix trace_output example 2016-04-28 17:29:45 -04:00
trace_output_user.c samples/bpf trace_output_user: Remove duplicate sys/ioctl.h include 2016-12-28 10:47:13 -03:00
tracex1_kern.c bpf, samples: don't zero data when not needed 2016-04-14 21:40:42 -04:00
tracex1_user.c samples/bpf: Add simple non-portable kprobe filter example 2015-04-02 13:25:50 +02:00
tracex2_kern.c bpf, samples: don't zero data when not needed 2016-04-14 21:40:42 -04:00
tracex2_user.c samples/bpf: Make samples more libbpf-centric 2016-12-15 16:25:47 -03:00
tracex3_kern.c samples/bpf: update tracex[23] examples to use per-cpu maps 2016-02-06 03:34:36 -05:00
tracex3_user.c samples/bpf: Make samples more libbpf-centric 2016-12-15 16:25:47 -03:00
tracex4_kern.c samples/bpf: Enable powerpc support 2016-04-06 16:01:29 -04:00
tracex4_user.c samples/bpf: Make samples more libbpf-centric 2016-12-15 16:25:47 -03:00
tracex5_kern.c samples/bpf: Add missing header 2017-02-13 17:22:35 -03:00
tracex5_user.c bpf samples: update tracex5 sample to use __seccomp_filter 2016-09-27 03:48:58 -04:00
tracex6_kern.c bpf: fix build warnings and add function read_trace_pipe() 2015-08-12 16:39:12 -07:00
tracex6_user.c samples/bpf: Remove perf_event_open() declaration 2016-12-20 12:00:40 -03:00
xdp1_kern.c bpf: make xdp sample variable names more meaningful 2016-07-20 22:07:24 -07:00
xdp1_user.c samples/bpf: Make samples more libbpf-centric 2016-12-15 16:25:47 -03:00
xdp2_kern.c bpf: make xdp sample variable names more meaningful 2016-07-20 22:07:24 -07:00
xdp_tx_iptunnel_common.h bpf: xdp: Add XDP example for head adjustment 2016-12-08 14:25:13 -05:00
xdp_tx_iptunnel_kern.c bpf: fix samples xdp_tx_iptunnel and tc_l2_redirect with fake KBUILD_MODNAME 2017-01-20 12:04:07 -05:00
xdp_tx_iptunnel_user.c samples/bpf: Make samples more libbpf-centric 2016-12-15 16:25:47 -03:00

README.rst

eBPF sample programs
====================

This directory contains a test stubs, verifier test-suite and examples
for using eBPF. The examples use libbpf from tools/lib/bpf.

Build dependencies
==================

Compiling requires having installed:
 * clang >= version 3.4.0
 * llvm >= version 3.7.1

Note that LLVM's tool 'llc' must support target 'bpf', list version
and supported targets with command: ``llc --version``

Kernel headers
--------------

There are usually dependencies to header files of the current kernel.
To avoid installing devel kernel headers system wide, as a normal
user, simply call::

 make headers_install

This will creates a local "usr/include" directory in the git/build top
level directory, that the make system automatically pickup first.

Compiling
=========

For building the BPF samples, issue the below command from the kernel
top level directory::

 make samples/bpf/

Do notice the "/" slash after the directory name.

It is also possible to call make from this directory.  This will just
hide the the invocation of make as above with the appended "/".

Manually compiling LLVM with 'bpf' support
------------------------------------------

Since version 3.7.0, LLVM adds a proper LLVM backend target for the
BPF bytecode architecture.

By default llvm will build all non-experimental backends including bpf.
To generate a smaller llc binary one can use::

 -DLLVM_TARGETS_TO_BUILD="BPF"

Quick sniplet for manually compiling LLVM and clang
(build dependencies are cmake and gcc-c++)::

 $ git clone http://llvm.org/git/llvm.git
 $ cd llvm/tools
 $ git clone --depth 1 http://llvm.org/git/clang.git
 $ cd ..; mkdir build; cd build
 $ cmake .. -DLLVM_TARGETS_TO_BUILD="BPF;X86"
 $ make -j $(getconf _NPROCESSORS_ONLN)

It is also possible to point make to the newly compiled 'llc' or
'clang' command via redefining LLC or CLANG on the make command line::

 make samples/bpf/ LLC=~/git/llvm/build/bin/llc CLANG=~/git/llvm/build/bin/clang