[PATCH] perf test: Remove perf sub test 42.4 BPF relocation checker

[PATCH] perf test: Remove perf sub test 42.4 BPF relocation checker

[Thomas Richter]

For some time now the perf test 42: BPF filter returns an error
on bpf relocation subtest, at least on x86 and s390. This is caused by

commit d859900c4c56 ("bpf, libbpf: support global data/bss/rodata sections")

which introduces support for global variables in eBPF programs.

Perf test 42.4 checks that the eBPF relocation fails when the eBPF program
contains a global variable. It returns OK when the eBPF program
could not be loaded and FAILED otherwise.

With above commit the test logic for the eBPF relocation is obsolete.
The loading of the eBPF now succeeds and the test always shows FAILED.

This patch removes the sub test completely.
Also a lot of eBPF program testing is done in the eBPF test suite,
it also contains tests for global variables.

Output before:
 42: BPF filter                          :
 42.1: Basic BPF filtering               : Ok
 42.2: BPF pinning                       : Ok
 42.3: BPF prologue generation           : Ok
 42.4: BPF relocation checker            : Failed
 #

Output after:
 # ./perf test -F 42
 42: BPF filter                          :
 42.1: Basic BPF filtering               : Ok
 42.2: BPF pinning                       : Ok
 42.3: BPF prologue generation           : Ok
 #

Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
---
 tools/perf/tests/bpf.c | 9 +--------
 1 file changed, 1 insertion(+), 8 deletions(-)

diff --git a/tools/perf/tests/bpf.c b/tools/perf/tests/bpf.c
index f57e075b0ed2..c72adbd67386 100644
--- a/tools/perf/tests/bpf.c
+++ b/tools/perf/tests/bpf.c
@@ -86,7 +86,7 @@ static struct {
 		.msg_load_fail	  = "check your vmlinux setting?",
 		.target_func	  = &epoll_pwait_loop,
 		.expect_result	  = (NR_ITERS + 1) / 2,
-		.pin 		  = true,
+		.pin		  = true,
 	},
 #ifdef HAVE_BPF_PROLOGUE
 	{
@@ -99,13 +99,6 @@ static struct {
 		.expect_result	  = (NR_ITERS + 1) / 4,
 	},
 #endif
-	{
-		.prog_id	  = LLVM_TESTCASE_BPF_RELOCATION,
-		.desc		  = "BPF relocation checker",
-		.name		  = "[bpf_relocation_test]",
-		.msg_compile_fail = "fix 'perf test LLVM' first",
-		.msg_load_fail	  = "libbpf error when dealing with relocation",
-	},
 };
 
 static int do_test(struct bpf_object *obj, int (*func)(void),
-- 
2.30.2

Re: [PATCH] perf test: Remove perf sub test 42.4 BPF relocation checker

[Arnaldo Carvalho de Melo]

Em Wed, Mar 24, 2021 at 09:37:34AM +0100, Thomas Richter escreveu:
> For some time now the perf test 42: BPF filter returns an error
> on bpf relocation subtest, at least on x86 and s390. This is caused by
> 
> commit d859900c4c56 ("bpf, libbpf: support global data/bss/rodata sections")
> 
> which introduces support for global variables in eBPF programs.
> 
> Perf test 42.4 checks that the eBPF relocation fails when the eBPF program
> contains a global variable. It returns OK when the eBPF program
> could not be loaded and FAILED otherwise.
> 
> With above commit the test logic for the eBPF relocation is obsolete.
> The loading of the eBPF now succeeds and the test always shows FAILED.
> 
> This patch removes the sub test completely.
> Also a lot of eBPF program testing is done in the eBPF test suite,
> it also contains tests for global variables.

Thanks, applied.

- Arnaldo