Hi Michael, thank you for your reply. On 28/05/2019 07:19, Michael Ellerman wrote: > Vincenzo Frascino <vincenzo.frascino@xxxxxxx> writes: > >> The current version of the multiarch vDSO selftest verifies only >> gettimeofday. >> >> Extend the vDSO selftest to clock_getres, to verify that the >> syscall and the vDSO library function return the same information. >> >> The extension has been used to verify the hrtimer_resoltion fix. > > This is passing for me even without patch 1 applied, shouldn't it fail > without the fix? What am I missing? > This is correct, because during the refactoring process I missed an "n" :) if·((x.tv_sec·!=·y.tv_sec)·||·(x.tv_sec·!=·y.tv_sec)) Should be: if·((x.tv_sec·!=·y.tv_sec)·||·(x.tv_nsec·!=·y.tv_nsec)) My mistake, I am going to fix the test and re-post v5 of this set. Without my patch if you pass "highres=off" to the kernel (as a command line parameter) it leads to a broken implementation of clock_getres since the value of CLOCK_REALTIME_RES does not change at runtime. Expected result (with highres=off): # uname -r 5.2.0-rc2 # ./vdso_clock_getres clock_id: CLOCK_REALTIME [FAIL] clock_id: CLOCK_BOOTTIME [PASS] clock_id: CLOCK_TAI [PASS] clock_id: CLOCK_REALTIME_COARSE [PASS] clock_id: CLOCK_MONOTONIC [FAIL] clock_id: CLOCK_MONOTONIC_RAW [PASS] clock_id: CLOCK_MONOTONIC_COARSE [PASS] The reason of this behavior is that the only clocks supported by getres on powerpc are CLOCK_REALTIME and CLOCK_MONOTONIC, the rest on the clocks use always syscalls. > # uname -r > 5.2.0-rc2-gcc-8.2.0 > > # ./vdso_clock_getres > clock_id: CLOCK_REALTIME [PASS] > clock_id: CLOCK_BOOTTIME [PASS] > clock_id: CLOCK_TAI [PASS] > clock_id: CLOCK_REALTIME_COARSE [PASS] > clock_id: CLOCK_MONOTONIC [PASS] > clock_id: CLOCK_MONOTONIC_RAW [PASS] > clock_id: CLOCK_MONOTONIC_COARSE [PASS] > > cheers > >> Cc: Shuah Khan <shuah@xxxxxxxxxx> >> Signed-off-by: Vincenzo Frascino <vincenzo.frascino@xxxxxxx> >> --- >> >> Note: This patch is independent from the others in this series, hence it >> can be merged singularly by the kselftest maintainers. >> >> tools/testing/selftests/vDSO/Makefile | 2 + >> .../selftests/vDSO/vdso_clock_getres.c | 124 ++++++++++++++++++ >> 2 files changed, 126 insertions(+) >> create mode 100644 tools/testing/selftests/vDSO/vdso_clock_getres.c -- Regards, Vincenzo
