Mark Salyzyn 79249b0897 bionic: add vdso clock_getres ... clock_getres() should not be a hot call, nevertheless it is ~6-7 times faster for supported clock ids if it uses __vdso_clock_getres if available. There is a 3% performance penalty for unsupported clock ids via __vdso_clock_getres with respect to a direct syscall. [TL;DR] w/vdso32 kernel patches, locked cores to MAX, little cores only. BEFORE: hikey960 vdso (aarch64): ---------------------------------------------------------------------- Benchmark Time CPU Iterations ---------------------------------------------------------------------- BM_time_clock_getres 126 ns 126 ns 5577874 BM_time_clock_getres_syscall 127 ns 127 ns 5505016 BM_time_clock_getres_REALTIME 126 ns 126 ns 5574682 BM_time_clock_getres_BOOTTIME 126 ns 126 ns 5575237 BM_time_clock_getres_TAI 126 ns 126 ns 5576810 BM_time_clock_getres_unsupported 128 ns 128 ns 5480189 hikey960 vdso32 (aarch32): ---------------------------------------------------------------------- Benchmark Time CPU Iterations ---------------------------------------------------------------------- BM_time_clock_getres 199 ns 199 ns 3508708 BM_time_clock_getres_syscall 220 ns 220 ns 3184676 BM_time_clock_getres_REALTIME 199 ns 199 ns 3509697 BM_time_clock_getres_BOOTTIME 199 ns 199 ns 3513551 BM_time_clock_getres_TAI 200 ns 199 ns 3512412 BM_time_clock_getres_unsupported 196 ns 196 ns 3575609 x86_64 (glibc): --------------------------------------------------------------------- Benchmark Time CPU Iterations --------------------------------------------------------------------- BM_time_clock_getres 252 ns 252 ns 2370263 BM_time_clock_getres_syscall 215 ns 215 ns 3287497 BM_time_clock_getres_REALTIME 214 ns 214 ns 3294228 BM_time_clock_getres_BOOTTIME 213 ns 213 ns 3277519 BM_time_clock_getres_TAI 213 ns 213 ns 3294991 BM_time_clock_getres_unsupported 206 ns 206 ns 3450654 imx7d_pico IOT nyc (w/arm,cpu-registers-not-fw-configured) (armv7a): (Virtual Timers) Benchmark Time(ns) CPU(ns) Iterations ------------------------------------------------------------------ BM_time_clock_getres 16 345 2000000 BM_time_clock_getres_syscall 16 339 2121212 BM_time_clock_getres_REALTIME 17 350 2058824 BM_time_clock_getres_BOOTTIME 17 345 2000000 BM_time_clock_getres_TAI 16 350 2000000 BM_time_clock_getres_unsupported 13 284 2500000 AFTER: hikey960 vdso (aarch64): --------------------------------------------------------------------- Benchmark Time CPU Iterations --------------------------------------------------------------------- BM_time_clock_getres 18 ns 18 ns 37880389 BM_time_clock_getres_syscall 127 ns 127 ns 5520029 BM_time_clock_getres_REALTIME 18 ns 18 ns 37879962 BM_time_clock_getres_BOOTTIME 19 ns 18 ns 37878361 BM_time_clock_getres_TAI 131 ns 131 ns 5368484 BM_time_clock_getres_unsupported 97 ns 97 ns 7182864 hikey960 vdso32 (aarch32): --------------------------------------------------------------------- Benchmark Time CPU Iterations --------------------------------------------------------------------- BM_time_clock_getres 36 ns 36 ns 19205240 BM_time_clock_getres_syscall 212 ns 212 ns 3297100 BM_time_clock_getres_REALTIME 36 ns 36 ns 19219109 BM_time_clock_getres_BOOTTIME 36 ns 36 ns 19222490 BM_time_clock_getres_TAI 206 ns 206 ns 3402868 BM_time_clock_getres_unsupported 159 ns 159 ns 4409492 imx7d_pico IOT nyc (wo/arm,cpu-registers-not-fw-configured) (armv7a): (Physical Timers) Benchmark Time(ns) CPU(ns) Iterations ------------------------------------------------------------------ BM_time_clock_getres 2 48 14000000 BM_time_clock_getres_syscall 14 335 2058824 BM_time_clock_getres_REALTIME 2 49 14583333 BM_time_clock_getres_BOOTTIME 2 48 14000000 BM_time_clock_getres_TAI 14 350 2058824 BM_time_clock_getres_unsupported 8 203 3500000 Test: taskset F \ /data/benchmarktest{64}/bionic-benchmarks/bionic-benchmarks \ --bionic_xml=vdso.xml --benchmark_filter=BM_time_clock_getres* Bug: 63737556 Change-Id: I80c0a5106625d76720287f715fcf145d2aad1705		2017-12-07 09:41:48 -08:00
..
bionic	Mark __BIONIC_WEAK_FOR_NATIVE_BRIDGE symbols	2017-10-27 10:01:46 +02:00
cortex-a53/bionic	libc: ARM64: update memset/strlen/memcpy/memmove to newlib/cortex-strings	2016-11-28 19:35:12 +00:00
denver64/bionic	Split our FORTIFY implementation into libc_fortify	2017-07-24 14:20:16 -07:00
generic/bionic	[AArch64] Optimized memcmp	2017-11-03 13:21:07 -04:00
syscalls	bionic: add vdso clock_getres	2017-12-07 09:41:48 -08:00