From: Andrei Vagin <avagin@xxxxxxxxx> [ Upstream commit c966533f8c6c45f93c52599f8460e7695f0b7eaa ] Performance numbers for Intel(R) Core(TM) i5-6300U CPU @ 2.40GHz (more clock_gettime() cycles - the better): clock | before | after | diff ---------------------------------------------------------- monotonic | 153222105 | 166775025 | 8.8% monotonic-coarse | 671557054 | 691513017 | 3.0% monotonic-raw | 147116067 | 161057395 | 9.5% boottime | 153446224 | 166962668 | 9.1% The improvement for arm64 for monotonic and boottime is around 3.5%. clock | before | after | diff ================================================== monotonic 17326692 17951770 3.6% monotonic-coarse 43624027 44215292 1.3% monotonic-raw 17541809 17554932 0.1% boottime 17334982 17954361 3.5% [ tglx: Avoid the goto ] Signed-off-by: Andrei Vagin <avagin@xxxxxxxxx> Signed-off-by: Dmitry Safonov <dima@xxxxxxxxxx> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20191112012724.250792-3-dima@xxxxxxxxxx Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- lib/vdso/gettimeofday.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/lib/vdso/gettimeofday.c b/lib/vdso/gettimeofday.c index c549e72758aa0..5667fb746a1fe 100644 --- a/lib/vdso/gettimeofday.c +++ b/lib/vdso/gettimeofday.c @@ -38,7 +38,7 @@ u64 vdso_calc_delta(u64 cycles, u64 last, u64 mask, u32 mult) } #endif -static int do_hres(const struct vdso_data *vd, clockid_t clk, +static __always_inline int do_hres(const struct vdso_data *vd, clockid_t clk, struct __kernel_timespec *ts) { const struct vdso_timestamp *vdso_ts = &vd->basetime[clk]; @@ -68,8 +68,8 @@ static int do_hres(const struct vdso_data *vd, clockid_t clk, return 0; } -static int do_coarse(const struct vdso_data *vd, clockid_t clk, - struct __kernel_timespec *ts) +static __always_inline int do_coarse(const struct vdso_data *vd, clockid_t clk, + struct __kernel_timespec *ts) { const struct vdso_timestamp *vdso_ts = &vd->basetime[clk]; u32 seq; @@ -99,13 +99,15 @@ __cvdso_clock_gettime_common(clockid_t clock, struct __kernel_timespec *ts) */ msk = 1U << clock; if (likely(msk & VDSO_HRES)) - return do_hres(&vd[CS_HRES_COARSE], clock, ts); + vd = &vd[CS_HRES_COARSE]; else if (msk & VDSO_COARSE) return do_coarse(&vd[CS_HRES_COARSE], clock, ts); else if (msk & VDSO_RAW) - return do_hres(&vd[CS_RAW], clock, ts); + vd = &vd[CS_RAW]; + else + return -1; - return -1; + return do_hres(vd, clock, ts); } static __maybe_unused int -- 2.35.1
