selftests/bpf: Restore original comm in test_overhead (e4300224) · Commits · 戴 / test

test_overhead changes task comm in order to estimate BPF trampoline overhead but never sets the comm back to the original one. We have the tests (like core_reloc.c) that have 'test_progs' as hard-coded expected comm, so let's try to preserve the original comm. Currently, everything works because the order of execution is: first core_recloc, then test_overhead; but let's make it a bit future-proof. Other related changes: use 'test_overhead' as new comm instead of 'test' to make it easy to debug and drop '\n' at the end. Signed-off-by:

Stanislav Fomichev <sdf@google.com> Signed-off-by:

Alexei Starovoitov <ast@kernel.org> Acked-by:

Petar Penkov <ppenkov@google.com> Acked-by:

Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20200108192132.189221-1-sdf@google.com

tools/testing/selftests/bpf/prog_tests/test_overhead.c

+7 −1

Original line number	Diff line number	Diff line
		@@ -2,6 +2,7 @@
		/* Copyright (c) 2019 Facebook */
		#define _GNU_SOURCE
		#include <sched.h>
		#include <sys/prctl.h>
		#include <test_progs.h>

		#define MAX_CNT 100000
		@@ -17,7 +18,7 @@ static __u64 time_get_ns(void)
		static int test_task_rename(const char *prog)
		{
		int i, fd, duration = 0, err;
		char buf[] = "test\n";
		char buf[] = "test_overhead";
		__u64 start_time;

		fd = open("/proc/self/comm", O_WRONLY\|O_TRUNC);
		@@ -66,6 +67,10 @@ void test_test_overhead(void)
		struct bpf_object *obj;
		struct bpf_link *link;
		int err, duration = 0;
		char comm[16] = {};

		if (CHECK_FAIL(prctl(PR_GET_NAME, comm, 0L, 0L, 0L)))
		return;

		obj = bpf_object__open_file("./test_overhead.o", NULL);
		if (CHECK(IS_ERR(obj), "obj_open_file", "err %ld\n", PTR_ERR(obj)))
		@@ -138,5 +143,6 @@ void test_test_overhead(void)
		test_run("fexit");
		bpf_link__destroy(link);
		cleanup:
		prctl(PR_SET_NAME, comm, 0L, 0L, 0L);
		bpf_object__close(obj);
		}

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