On 01/29/2016 10:32 PM, Hauke Mehrtens wrote: > When using the vdso clock_gettime() it looks like that the clock is > sometimes not going forward when the process sleeps and the clock also > sleeps. This problem only happens with the vdso clock and not with the > normal syscall clock. > > I wrote a small test program which calls the syscall and the vdso > version. In the first call they are showing the same time, but after I > sleeped for 1 second, they are off by one second. This problem occurs > not 100% reliable but I see it pretty often. Only the CLOCK_REALTIME and > CLOCK_MONOTONIC seam to be affected CLOCK_REALTIME_COARSE is not affected. > > I am using an MIPS BE 34Kc V5.6 CPU with two VPEs, but only one is used. > This is a Lantiq VRX200 SoC with OpenWrt Linux kernel 4.4 and musl libc. > > Hauke Hi, Any news on this? For me this is a usespace API regression. Should I send a patch deactivating the vdso support only for the MIPS 34Kc CPU or for completely for mips? Hauke > Here are my measurements: > > start test > syscall: CLOCK_REALTIME: tv_sec: 1454098944, tv_nsec: 463189916 > vdso: CLOCK_REALTIME: tv_sec: 1454098944, tv_nsec: 463242196 > syscall: CLOCK_REALTIME_COARSE: tv_sec: 1454098944, tv_nsec: 456000000 > vdso: CLOCK_REALTIME_COARSE: tv_sec: 1454098944, tv_nsec: 456000000 > syscall: CLOCK_MONOTONIC: tv_sec: 107, tv_nsec: 28113172 > vdso: CLOCK_MONOTONIC: tv_sec: 107, tv_nsec: 32150208 > syscall: CLOCK_MONOTONIC_COARSE: tv_sec: 107, tv_nsec: 24678324 > vdso: CLOCK_MONOTONIC_COARSE: tv_sec: 107, tv_nsec: 24678324 > syscall: CLOCK_MONOTONIC_RAW: tv_sec: 107, tv_nsec: 28263008 > vdso: CLOCK_MONOTONIC_RAW: tv_sec: 107, tv_nsec: 28300760 > syscall: CLOCK_BOOTTIME: tv_sec: 107, tv_nsec: 28337540 > vdso: CLOCK_BOOTTIME: tv_sec: 107, tv_nsec: 28379100 > syscall: CLOCK_PROCESS_CPUTIME_ID: tv_sec: 0, tv_nsec: 3111128 > vdso: CLOCK_PROCESS_CPUTIME_ID: tv_sec: 0, tv_nsec: 3153120 > syscall: CLOCK_THREAD_CPUTIME_ID: tv_sec: 0, tv_nsec: 3192208 > vdso: CLOCK_THREAD_CPUTIME_ID: tv_sec: 0, tv_nsec: 3231696 > sleep(1) > syscall: CLOCK_REALTIME: tv_sec: 1454098945, tv_nsec: 464023036 > vdso: CLOCK_REALTIME: tv_sec: 1454098946, tv_nsec: 468077456 > syscall: CLOCK_REALTIME_COARSE: tv_sec: 1454098945, tv_nsec: 460000000 > vdso: CLOCK_REALTIME_COARSE: tv_sec: 1454098945, tv_nsec: 460000000 > syscall: CLOCK_MONOTONIC: tv_sec: 108, tv_nsec: 28874940 > vdso: CLOCK_MONOTONIC: tv_sec: 109, tv_nsec: 32911852 > syscall: CLOCK_MONOTONIC_COARSE: tv_sec: 108, tv_nsec: 24678324 > vdso: CLOCK_MONOTONIC_COARSE: tv_sec: 108, tv_nsec: 24678324 > syscall: CLOCK_MONOTONIC_RAW: tv_sec: 108, tv_nsec: 29023384 > vdso: CLOCK_MONOTONIC_RAW: tv_sec: 108, tv_nsec: 29061372 > syscall: CLOCK_BOOTTIME: tv_sec: 108, tv_nsec: 29097912 > vdso: CLOCK_BOOTTIME: tv_sec: 108, tv_nsec: 29139864 > syscall: CLOCK_PROCESS_CPUTIME_ID: tv_sec: 0, tv_nsec: 3824540 > vdso: CLOCK_PROCESS_CPUTIME_ID: tv_sec: 0, tv_nsec: 3865708 > syscall: CLOCK_THREAD_CPUTIME_ID: tv_sec: 0, tv_nsec: 3904680 > vdso: CLOCK_THREAD_CPUTIME_ID: tv_sec: 0, tv_nsec: 3943892 > sleep(2) > syscall: CLOCK_REALTIME: tv_sec: 1454098947, tv_nsec: 464791376 > vdso: CLOCK_REALTIME: tv_sec: 1454098950, tv_nsec: 468847600 > syscall: CLOCK_REALTIME_COARSE: tv_sec: 1454098947, tv_nsec: 460000000 > vdso: CLOCK_REALTIME_COARSE: tv_sec: 1454098947, tv_nsec: 460000000 > syscall: CLOCK_MONOTONIC: tv_sec: 110, tv_nsec: 29644468 > vdso: CLOCK_MONOTONIC: tv_sec: 113, tv_nsec: 33682152 > syscall: CLOCK_MONOTONIC_COARSE: tv_sec: 110, tv_nsec: 24678324 > vdso: CLOCK_MONOTONIC_COARSE: tv_sec: 110, tv_nsec: 24678324 > syscall: CLOCK_MONOTONIC_RAW: tv_sec: 110, tv_nsec: 29794136 > vdso: CLOCK_MONOTONIC_RAW: tv_sec: 110, tv_nsec: 29831728 > syscall: CLOCK_BOOTTIME: tv_sec: 110, tv_nsec: 29868576 > vdso: CLOCK_BOOTTIME: tv_sec: 110, tv_nsec: 29909920 > syscall: CLOCK_PROCESS_CPUTIME_ID: tv_sec: 0, tv_nsec: 4547416 > vdso: CLOCK_PROCESS_CPUTIME_ID: tv_sec: 0, tv_nsec: 4589684 > syscall: CLOCK_THREAD_CPUTIME_ID: tv_sec: 0, tv_nsec: 4628872 > vdso: CLOCK_THREAD_CPUTIME_ID: tv_sec: 0, tv_nsec: 4668808 > sleep(3) > syscall: CLOCK_REALTIME: tv_sec: 1454098950, tv_nsec: 465558716 > vdso: CLOCK_REALTIME: tv_sec: 1454098956, tv_nsec: 469613960 > syscall: CLOCK_REALTIME_COARSE: tv_sec: 1454098950, tv_nsec: 460000000 > vdso: CLOCK_REALTIME_COARSE: tv_sec: 1454098950, tv_nsec: 460000000 > syscall: CLOCK_MONOTONIC: tv_sec: 113, tv_nsec: 30411308 > vdso: CLOCK_MONOTONIC: tv_sec: 119, tv_nsec: 34448236 > syscall: CLOCK_MONOTONIC_COARSE: tv_sec: 113, tv_nsec: 24678324 > vdso: CLOCK_MONOTONIC_COARSE: tv_sec: 113, tv_nsec: 24678324 > syscall: CLOCK_MONOTONIC_RAW: tv_sec: 113, tv_nsec: 30559184 > vdso: CLOCK_MONOTONIC_RAW: tv_sec: 113, tv_nsec: 30596676 > syscall: CLOCK_BOOTTIME: tv_sec: 113, tv_nsec: 30632568 > vdso: CLOCK_BOOTTIME: tv_sec: 113, tv_nsec: 30673204 > syscall: CLOCK_PROCESS_CPUTIME_ID: tv_sec: 0, tv_nsec: 5262328 > vdso: CLOCK_PROCESS_CPUTIME_ID: tv_sec: 0, tv_nsec: 5304576 > syscall: CLOCK_THREAD_CPUTIME_ID: tv_sec: 0, tv_nsec: 5343136 > vdso: CLOCK_THREAD_CPUTIME_ID: tv_sec: 0, tv_nsec: 5382616 >
