Adhemerval Zanella 92b963699a linux: Optimize fallback 32-bit clock_getres ... This patch avoid probing the __NR_clock_getttime64 syscall each time __clock_gettime64 is issued on a kernel without 64 bit time support. Once ENOSYS is obtained, only 32-bit clock_gettime are used. The following snippet: clock_getres (CLOCK_REALTIME, &(struct timespec) { 0 }); clock_getres (CLOCK_MONOTONIC, &(struct timespec) { 0 }); clock_getres (CLOCK_BOOTTIME, &(struct timespec) { 0 }); clock_getres (20, &(struct timespec) { 0 }); On a kernel without 64 bit time support issues the syscalls: syscall_0x196(0, 0xffb83330, [...]) = -1 ENOSYS (Function not implemented) clock_getres(CLOCK_REALTIME, {tv_sec=0, tv_nsec=1}) = 0 clock_getres(CLOCK_MONOTONIC, {tv_sec=0, tv_nsec=1}) = 0 clock_getres(CLOCK_BOOTTIME, {tv_sec=0, tv_nsec=1}) = 0 Checked on i686-linux-gnu on 4.15 kernel. Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>		2020-01-03 11:22:07 -03:00
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linux	linux: Optimize fallback 32-bit clock_getres	2020-01-03 11:22:07 -03:00