selftests/bpf: fix lots of silly mistakes pointed out by compiler

Once we enable -Wall for BPF sources, compiler will complain about lots
of unused variables, variables that are set but never read,

selftests/bpf: fix lots of silly mistakes pointed out by compiler

Once we enable -Wall for BPF sources, compiler will complain about lots
of unused variables, variables that are set but never read, etc.

Fix all these issues first before enabling -Wall in Makefile.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230309054015.4068562-4-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

show more ...

selftests/bpf: add bpf_for_each(), bpf_for(), and bpf_repeat() macros

Add bpf_for_each(), bpf_for(), and bpf_repeat() macros that make writing
open-coded iterator-based loops much more convenient an

selftests/bpf: add bpf_for_each(), bpf_for(), and bpf_repeat() macros

Add bpf_for_each(), bpf_for(), and bpf_repeat() macros that make writing
open-coded iterator-based loops much more convenient and natural. These
macros utilize cleanup attribute to ensure proper destruction of the
iterator and thanks to that manage to provide the ergonomics that is
very close to C language's for() construct. Typical loop would look like:

int i;
int arr[N];

bpf_for(i, 0, N) {
/* verifier will know that i >= 0 && i < N, so could be used to
* directly access array elements with no extra checks
*/
arr[i] = i;
}

bpf_repeat() is very similar, but it doesn't expose iteration number and
is meant as a simple "repeat action N times" loop:

bpf_repeat(N) { /* whatever, N times */ }

Note that `break` and `continue` statements inside the {} block work as
expected.

bpf_for_each() is a generalization over any kind of BPF open-coded
iterator allowing to use for-each-like approach instead of calling
low-level bpf_iter_<type>_{new,next,destroy}() APIs explicitly. E.g.:

struct cgroup *cg;

bpf_for_each(cgroup, cg, some, input, args) {
/* do something with each cg */
}

would call (not-yet-implemented) bpf_iter_cgroup_{new,next,destroy}()
functions to form a loop over cgroups, where `some, input, args` are
passed verbatim into constructor as

bpf_iter_cgroup_new(&it, some, input, args).

As a first demonstration, add pyperf variant based on the bpf_for() loop.

Also clean up a few tests that either included bpf_misc.h header
unnecessarily from the user-space, which is unsupported, or included it
before any common types are defined (and thus leading to unnecessary
compilation warnings, potentially).

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230308184121.1165081-6-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

show more ...

libbpf: Provide barrier() and barrier_var() in bpf_helpers.h

Add barrier() and barrier_var() macros into bpf_helpers.h to be used by
end users. While a bit advanced and specialized instruments, they

libbpf: Provide barrier() and barrier_var() in bpf_helpers.h

Add barrier() and barrier_var() macros into bpf_helpers.h to be used by
end users. While a bit advanced and specialized instruments, they are
sometimes indispensable. Instead of requiring each user to figure out
exact asm volatile incantations for themselves, provide them from
bpf_helpers.h.

Also remove conflicting definitions from selftests. Some tests rely on
barrier_var() definition being nothing, those will still work as libbpf
does the #ifndef/#endif guarding for barrier() and barrier_var(),
allowing users to redefine them, if necessary.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220509004148.1801791-8-andrii@kernel.org

show more ...

selftests/bpf: Limit unroll_count for pyperf600 test

LLVM commit [1] changed loop pragma behavior such that
full loop unroll is always honored with user pragma.
Previously, unroll count also depends

selftests/bpf: Limit unroll_count for pyperf600 test

LLVM commit [1] changed loop pragma behavior such that
full loop unroll is always honored with user pragma.
Previously, unroll count also depends on the unrolled
code size. For pyperf600, without [1], the loop unroll
count is 150. With [1], the loop unroll count is 600.

The unroll count of 600 caused the program size close to
298k and this caused the following code is generated:
0: 7b 1a 00 ff 00 00 00 00 *(u64 *)(r10 - 256) = r1
; uint64_t pid_tgid = bpf_get_current_pid_tgid();
1: 85 00 00 00 0e 00 00 00 call 14
2: bf 06 00 00 00 00 00 00 r6 = r0
; pid_t pid = (pid_t)(pid_tgid >> 32);
3: bf 61 00 00 00 00 00 00 r1 = r6
4: 77 01 00 00 20 00 00 00 r1 >>= 32
5: 63 1a fc ff 00 00 00 00 *(u32 *)(r10 - 4) = r1
6: bf a2 00 00 00 00 00 00 r2 = r10
7: 07 02 00 00 fc ff ff ff r2 += -4
; PidData* pidData = bpf_map_lookup_elem(&pidmap, &pid);
8: 18 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 r1 = 0 ll
10: 85 00 00 00 01 00 00 00 call 1
11: bf 08 00 00 00 00 00 00 r8 = r0
; if (!pidData)
12: 15 08 15 e8 00 00 00 00 if r8 == 0 goto -6123 <LBB0_27588+0xffffffffffdae100>

Note that insn 12 has a branch offset -6123 which is clearly illegal
and will be rejected by the verifier. The negative offset is due to
the branch range is greater than INT16_MAX.

This patch changed the unroll count to be 150 to avoid above
branch target insn out-of-range issue. Also the llvm is enhanced ([2])
to assert if the branch target insn is out of INT16 range.

[1] https://reviews.llvm.org/D119148
[2] https://reviews.llvm.org/D123877

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220419043230.2928530-1-yhs@fb.com

show more ...

selftests/bpf: Measure bpf_loop verifier performance

This patch tests bpf_loop in pyperf and strobemeta, and measures the
verifier performance of replacing the traditional for loop
with bpf_loop.

T

selftests/bpf: Measure bpf_loop verifier performance

This patch tests bpf_loop in pyperf and strobemeta, and measures the
verifier performance of replacing the traditional for loop
with bpf_loop.

The results are as follows:

~strobemeta~

Baseline
verification time 6808200 usec
stack depth 496
processed 554252 insns (limit 1000000) max_states_per_insn 16
total_states 15878 peak_states 13489 mark_read 3110
#192 verif_scale_strobemeta:OK (unrolled loop)

Using bpf_loop
verification time 31589 usec
stack depth 96+400
processed 1513 insns (limit 1000000) max_states_per_insn 2
total_states 106 peak_states 106 mark_read 60
#193 verif_scale_strobemeta_bpf_loop:OK

~pyperf600~

Baseline
verification time 29702486 usec
stack depth 368
processed 626838 insns (limit 1000000) max_states_per_insn 7
total_states 30368 peak_states 30279 mark_read 748
#182 verif_scale_pyperf600:OK (unrolled loop)

Using bpf_loop
verification time 148488 usec
stack depth 320+40
processed 10518 insns (limit 1000000) max_states_per_insn 10
total_states 705 peak_states 517 mark_read 38
#183 verif_scale_pyperf600_bpf_loop:OK

Using the bpf_loop helper led to approximately a 99% decrease
in the verification time and in the number of instructions.

Signed-off-by: Joanne Koong <joannekoong@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211130030622.4131246-4-joannekoong@fb.com

show more ...

selftests/bpf: Add subprogs to pyperf, strobemeta, and l4lb_noinline tests

Add use of non-inlined subprogs to few bigger selftests to excercise libbpf's
bpf2bpf handling logic. Also split l4lb_all s

selftests/bpf: Add subprogs to pyperf, strobemeta, and l4lb_noinline tests

Add use of non-inlined subprogs to few bigger selftests to excercise libbpf's
bpf2bpf handling logic. Also split l4lb_all selftest into two sub-tests.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200903203542.15944-13-andriin@fb.com

show more ...

selftests: Use consistent include paths for libbpf

Fix all selftests to include libbpf header files with the bpf/ prefix, to
be consistent with external users of the library. Also ensure that all
in

selftests: Use consistent include paths for libbpf

Fix all selftests to include libbpf header files with the bpf/ prefix, to
be consistent with external users of the library. Also ensure that all
includes of exported libbpf header files (those that are exported on 'make
install' of the library) use bracketed includes instead of quoted.

To not break the build, keep the old include path until everything has been
changed to the new one; a subsequent patch will remove that.

Fixes: 6910d7d3867a ("selftests/bpf: Ensure bpf_helper_defs.h are taken from selftests dir")
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/157952560568.1683545.9649335788846513446.stgit@toke.dk

show more ...

selftests/bpf: Add a test for a large global function

test results:
pyperf50 with always_inlined the same function five times: processed 46378 insns
pyperf50 with global function: processed 6102 ins

selftests/bpf: Add a test for a large global function

test results:
pyperf50 with always_inlined the same function five times: processed 46378 insns
pyperf50 with global function: processed 6102 insns

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20200110064124.1760511-5-ast@kernel.org

show more ...

bpf, testing: Convert prog tests to probe_read_{user, kernel}{, _str} helper

Use probe read *_{kernel,user}{,_str}() helpers instead of bpf_probe_read()
or bpf_probe_read_user_str() for program test

bpf, testing: Convert prog tests to probe_read_{user, kernel}{, _str} helper

Use probe read *_{kernel,user}{,_str}() helpers instead of bpf_probe_read()
or bpf_probe_read_user_str() for program tests where appropriate.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/4a61d4b71ce3765587d8ef5cb93afa18515e5b3e.1572649915.git.daniel@iogearbox.net

show more ...

selftests/bpf: convert legacy BPF maps to BTF-defined ones

Convert selftests that were originally left out and new ones added
recently to consistently use BTF-defined maps.

Reported-by: kernel test

selftests/bpf: convert legacy BPF maps to BTF-defined ones

Convert selftests that were originally left out and new ones added
recently to consistently use BTF-defined maps.

Reported-by: kernel test robot <rong.a.chen@intel.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

show more ...

selftests: bpf: standardize to static __always_inline

The progs for bpf selftests use several different notations to force
function inlining. Standardize to what most of them use,
static __always_in

selftests: bpf: standardize to static __always_inline

The progs for bpf selftests use several different notations to force
function inlining. Standardize to what most of them use,
static __always_inline.

Suggested-by: Song Liu <liu.song.a23@gmail.com>
Signed-off-by: Jiri Benc <jbenc@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

show more ...

selftests/bpf: add realistic loop tests

Add a bunch of loop tests. Most of them are created by replacing
'#pragma unroll' with '#pragma clang loop unroll(disable)'

Several tests are artificially la

selftests/bpf: add realistic loop tests

Add a bunch of loop tests. Most of them are created by replacing
'#pragma unroll' with '#pragma clang loop unroll(disable)'

Several tests are artificially large:
/* partial unroll. llvm will unroll loop ~150 times.
* C loop count -> 600.
* Asm loop count -> 4.
* 16k insns in loop body.
* Total of 5 such loops. Total program size ~82k insns.
*/
"./pyperf600.o",

/* no unroll at all.
* C loop count -> 600.
* ASM loop count -> 600.
* ~110 insns in loop body.
* Total of 5 such loops. Total program size ~1500 insns.
*/
"./pyperf600_nounroll.o",

/* partial unroll. 19k insn in a loop.
* Total program size 20.8k insn.
* ~350k processed_insns
*/
"./strobemeta.o",

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

show more ...

selftests/bpf: add pyperf scale test

Add a snippet of pyperf bpf program used to collect python stack traces
as a scale test for the verifier.

At 189 loop iterations llvm 9.0 starts ignoring '#prag

selftests/bpf: add pyperf scale test

Add a snippet of pyperf bpf program used to collect python stack traces
as a scale test for the verifier.

At 189 loop iterations llvm 9.0 starts ignoring '#pragma unroll'
and generates partially unrolled loop instead.
Hence use 50, 100, and 180 loop iterations to stress test.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

show more ...

selftests/bpf: Add subprogs to pyperf, strobemeta, and l4lb_noinline tests

Add use of non-inlined subprogs to few bigger selftests to excercise libbpf's
bpf2bpf handling logic. Also spli

selftests/bpf: Add subprogs to pyperf, strobemeta, and l4lb_noinline tests

Add use of non-inlined subprogs to few bigger selftests to excercise libbpf's
bpf2bpf handling logic. Also split l4lb_all selftest into two sub-tests.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200903203542.15944-13-andriin@fb.com

show more ...

selftests: Use consistent include paths for libbpf

Fix all selftests to include libbpf header files with the bpf/ prefix, to
be consistent with external users of the library. Also ensure

selftests: Use consistent include paths for libbpf

Fix all selftests to include libbpf header files with the bpf/ prefix, to
be consistent with external users of the library. Also ensure that all
includes of exported libbpf header files (those that are exported on 'make
install' of the library) use bracketed includes instead of quoted.

To not break the build, keep the old include path until everything has been
changed to the new one; a subsequent patch will remove that.

Fixes: 6910d7d3867a ("selftests/bpf: Ensure bpf_helper_defs.h are taken from selftests dir")
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/157952560568.1683545.9649335788846513446.stgit@toke.dk

show more ...

selftests/bpf: Add a test for a large global function

test results:
pyperf50 with always_inlined the same function five times: processed 46378 insns
pyperf50 with global function: pr

selftests/bpf: Add a test for a large global function

test results:
pyperf50 with always_inlined the same function five times: processed 46378 insns
pyperf50 with global function: processed 6102 insns

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20200110064124.1760511-5-ast@kernel.org

show more ...

bpf, testing: Convert prog tests to probe_read_{user, kernel}{, _str} helper

Use probe read *_{kernel,user}{,_str}() helpers instead of bpf_probe_read()
or bpf_probe_read_user_str() for

bpf, testing: Convert prog tests to probe_read_{user, kernel}{, _str} helper

Use probe read *_{kernel,user}{,_str}() helpers instead of bpf_probe_read()
or bpf_probe_read_user_str() for program tests where appropriate.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/4a61d4b71ce3765587d8ef5cb93afa18515e5b3e.1572649915.git.daniel@iogearbox.net

show more ...

selftests/bpf: convert legacy BPF maps to BTF-defined ones

Convert selftests that were originally left out and new ones added
recently to consistently use BTF-defined maps.

Repo

selftests/bpf: convert legacy BPF maps to BTF-defined ones

Convert selftests that were originally left out and new ones added
recently to consistently use BTF-defined maps.

Reported-by: kernel test robot <rong.a.chen@intel.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

show more ...

selftests: bpf: standardize to static __always_inline

The progs for bpf selftests use several different notations to force
function inlining. Standardize to what most of them use,
st

selftests: bpf: standardize to static __always_inline

The progs for bpf selftests use several different notations to force
function inlining. Standardize to what most of them use,
static __always_inline.

Suggested-by: Song Liu <liu.song.a23@gmail.com>
Signed-off-by: Jiri Benc <jbenc@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

show more ...

selftests/bpf: add realistic loop tests

Add a bunch of loop tests. Most of them are created by replacing
'#pragma unroll' with '#pragma clang loop unroll(disable)'

Several tests

selftests/bpf: add realistic loop tests

Add a bunch of loop tests. Most of them are created by replacing
'#pragma unroll' with '#pragma clang loop unroll(disable)'

Several tests are artificially large:
/* partial unroll. llvm will unroll loop ~150 times.
* C loop count -> 600.
* Asm loop count -> 4.
* 16k insns in loop body.
* Total of 5 such loops. Total program size ~82k insns.
*/
"./pyperf600.o",

/* no unroll at all.
* C loop count -> 600.
* ASM loop count -> 600.
* ~110 insns in loop body.
* Total of 5 such loops. Total program size ~1500 insns.
*/
"./pyperf600_nounroll.o",

/* partial unroll. 19k insn in a loop.
* Total program size 20.8k insn.
* ~350k processed_insns
*/
"./strobemeta.o",

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

show more ...

selftests/bpf: add pyperf scale test

Add a snippet of pyperf bpf program used to collect python stack traces
as a scale test for the verifier.

At 189 loop iterations llvm 9.0 st

selftests/bpf: add pyperf scale test

Add a snippet of pyperf bpf program used to collect python stack traces
as a scale test for the verifier.

At 189 loop iterations llvm 9.0 starts ignoring '#pragma unroll'
and generates partially unrolled loop instead.
Hence use 50, 100, and 180 loop iterations to stress test.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

show more ...