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selftests/bpf: Skip the second half of get_branch_snapshot in vm

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VMs running on upstream 5.12+ kernel support LBR. However,
bpf_get_branch_snapshot couldn't stop the LBR before too many entries
are flushed. Skip the hit/waste test for VMs before we find a proper fix
for LBR in VM.

Fixes: 025bd7c753 ("selftests/bpf: Add test for bpf_get_branch_snapshot")
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211007050231.728496-1-songliubraving@fb.com
This commit is contained in:
Song Liu 2021-10-06 22:02:31 -07:00 committed by Andrii Nakryiko
parent 0eb4ef88c5
commit aa67fdb464
1 changed files with 34 additions and 0 deletions
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34
tools/testing/selftests/bpf/prog_tests/get_branch_snapshot.c
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@ -6,6 +6,30 @@
static int *pfd_array; static int *pfd_array;
static int cpu_cnt; static int cpu_cnt;
static bool is_hypervisor(void)
{
char *line = NULL;
bool ret = false;
size_t len;
FILE *fp;
fp = fopen("/proc/cpuinfo", "r");
if (!fp)
return false;
while (getline(&line, &len, fp) != -1) {
if (!strncmp(line, "flags", 5)) {
if (strstr(line, "hypervisor") != NULL)
ret = true;
break;
}
}
free(line);
fclose(fp);
return ret;
}
static int create_perf_events(void) static int create_perf_events(void)
{ {
struct perf_event_attr attr = {0}; struct perf_event_attr attr = {0};
@ -83,6 +107,16 @@ void test_get_branch_snapshot(void)
goto cleanup; goto cleanup;
} }
if (is_hypervisor()) {
/* As of today, LBR in hypervisor cannot be stopped before
* too many entries are flushed. Skip the hit/waste test
* for now in hypervisor until we optimize the LBR in
* hypervisor.
*/
test__skip();
goto cleanup;
}
ASSERT_GT(skel->bss->test1_hits, 6, "find_looptest_in_lbr"); ASSERT_GT(skel->bss->test1_hits, 6, "find_looptest_in_lbr");
/* Given we stop LBR in software, we will waste a few entries. /* Given we stop LBR in software, we will waste a few entries.