| Message ID | 20221220-arm64-fp-stress-pow2-v1-1-d0ce756b57af@kernel.org (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 67f49869106f78882a8a09b736d4884be85aba18 |
| Headers | show |
| Series | kselftest/arm64: Skip non-power of 2 SVE vector lengths in fp-stress | expand |
On Tue, 27 Dec 2022 13:07:45 +0000, Mark Brown wrote: > As documented in issue C215 in the known issues list for DDI0487I.a [1] Arm > will be making a retroactive change to SVE to remove the possibility of > selecting non power of two vector lengths. This has no impact on existing > physical implementations but most virtual implementations have implemented > the full range of permissible vector lengths. Given how demanding fp-stress > is for these implementations update to only attempt to enumerate the power > of two vector lengths, reducing the load created on existing virtual > implementations and only exercising the functionality that will be seen in > physical implementations. > > [...] Applied to arm64 (for-next/kselftest), thanks! [1/1] kselftest/arm64: Skip non-power of 2 SVE vector lengths in fp-stress https://git.kernel.org/arm64/c/67f49869106f
diff --git a/tools/testing/selftests/arm64/fp/fp-stress.c b/tools/testing/selftests/arm64/fp/fp-stress.c index f8b2f41aac36..2b95f9451b1b 100644 --- a/tools/testing/selftests/arm64/fp/fp-stress.c +++ b/tools/testing/selftests/arm64/fp/fp-stress.c @@ -377,7 +377,7 @@ static void probe_vls(int vls[], int *vl_count, int set_vl) *vl_count = 0; - for (vq = SVE_VQ_MAX; vq > 0; --vq) { + for (vq = SVE_VQ_MAX; vq > 0; vq /= 2) { vl = prctl(set_vl, vq * 16); if (vl == -1) ksft_exit_fail_msg("SET_VL failed: %s (%d)\n", @@ -385,6 +385,9 @@ static void probe_vls(int vls[], int *vl_count, int set_vl) vl &= PR_SVE_VL_LEN_MASK; + if (*vl_count && (vl == vls[*vl_count - 1])) + break; + vq = sve_vq_from_vl(vl); vls[*vl_count] = vl;
As documented in issue C215 in the known issues list for DDI0487I.a [1] Arm will be making a retroactive change to SVE to remove the possibility of selecting non power of two vector lengths. This has no impact on existing physical implementations but most virtual implementations have implemented the full range of permissible vector lengths. Given how demanding fp-stress is for these implementations update to only attempt to enumerate the power of two vector lengths, reducing the load created on existing virtual implementations and only exercising the functionality that will be seen in physical implementations. [1] https://developer.arm.com/documentation/102105/ia-00/ Signed-off-by: Mark Brown <broonie@kernel.org> --- tools/testing/selftests/arm64/fp/fp-stress.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- base-commit: 1b929c02afd37871d5afb9d498426f83432e71c2 change-id: 20221220-arm64-fp-stress-pow2-b81ee6471492 Best regards,