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| author | Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> | 2018-10-23 10:04:56 +0200 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2018-10-30 13:11:04 +0100 |
| commit | a95ecac5cb2fc8a8ee606991384d33ee121df00c (patch) | |
| tree | 5800835c357eb44f584c16c572b0b9ab16e489ef /tools | |
| parent | Merge branch 'next' of https://git.kernel.org/pub/scm/linux/kernel/git/scottw... (diff) | |
| download | linux-a95ecac5cb2fc8a8ee606991384d33ee121df00c.tar.xz linux-a95ecac5cb2fc8a8ee606991384d33ee121df00c.zip | |
selftests/powerpc: Relax L1d miss targets for rfi_flush test
When running the rfi_flush test, if the system is loaded, we see two
issues:
1. The L1d misses when rfi_flush is disabled increase significantly due
to other workloads interfering with the cache.
2. The L1d misses when rfi_flush is enabled sometimes goes slightly
below the expected number of misses.
To address these, let's relax the expected number of L1d misses:
1. When rfi_flush is disabled, we allow upto half the expected number of
the misses for when rfi_flush is enabled.
2. When rfi_flush is enabled, we allow ~1% lower number of cache misses.
Reported-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Tested-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/testing/selftests/powerpc/security/rfi_flush.c | 18 |
1 files changed, 13 insertions, 5 deletions
diff --git a/tools/testing/selftests/powerpc/security/rfi_flush.c b/tools/testing/selftests/powerpc/security/rfi_flush.c index 564ed45bbf73..0a7d0afb26b8 100644 --- a/tools/testing/selftests/powerpc/security/rfi_flush.c +++ b/tools/testing/selftests/powerpc/security/rfi_flush.c @@ -49,6 +49,7 @@ int rfi_flush_test(void) struct perf_event_read v; __u64 l1d_misses_total = 0; unsigned long iterations = 100000, zero_size = 24 * 1024; + unsigned long l1d_misses_expected; int rfi_flush_org, rfi_flush; SKIP_IF(geteuid() != 0); @@ -71,6 +72,12 @@ int rfi_flush_test(void) iter = repetitions; + /* + * We expect to see l1d miss for each cacheline access when rfi_flush + * is set. Allow a small variation on this. + */ + l1d_misses_expected = iterations * (zero_size / CACHELINE_SIZE - 2); + again: FAIL_IF(perf_event_reset(fd)); @@ -78,10 +85,9 @@ again: FAIL_IF(read(fd, &v, sizeof(v)) != sizeof(v)); - /* Expect at least zero_size/CACHELINE_SIZE misses per iteration */ - if (v.l1d_misses >= (iterations * zero_size / CACHELINE_SIZE) && rfi_flush) + if (rfi_flush && v.l1d_misses >= l1d_misses_expected) passes++; - else if (v.l1d_misses < iterations && !rfi_flush) + else if (!rfi_flush && v.l1d_misses < (l1d_misses_expected / 2)) passes++; l1d_misses_total += v.l1d_misses; @@ -92,13 +98,15 @@ again: if (passes < repetitions) { printf("FAIL (L1D misses with rfi_flush=%d: %llu %c %lu) [%d/%d failures]\n", rfi_flush, l1d_misses_total, rfi_flush ? '<' : '>', - rfi_flush ? (repetitions * iterations * zero_size / CACHELINE_SIZE) : iterations, + rfi_flush ? repetitions * l1d_misses_expected : + repetitions * l1d_misses_expected / 2, repetitions - passes, repetitions); rc = 1; } else printf("PASS (L1D misses with rfi_flush=%d: %llu %c %lu) [%d/%d pass]\n", rfi_flush, l1d_misses_total, rfi_flush ? '>' : '<', - rfi_flush ? (repetitions * iterations * zero_size / CACHELINE_SIZE) : iterations, + rfi_flush ? repetitions * l1d_misses_expected : + repetitions * l1d_misses_expected / 2, passes, repetitions); if (rfi_flush == rfi_flush_org) { |