>From 5252093fec4c74802e5ef501b9f1db3369430c80 Mon Sep 17 00:00:00 2001 From: Andrei Vagin Date: Tue, 22 Oct 2019 18:23:17 -0700 Subject: [PATCH] lib/vdso: make do_hres and do_coarse as __always_inline 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% Signed-off-by: Andrei Vagin --- lib/vdso/gettimeofday.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/lib/vdso/gettimeofday.c b/lib/vdso/gettimeofday.c index e630e7ff57f1..b4f7f0f246af 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]; @@ -68,7 +68,7 @@ static int do_hres(const struct vdso_data *vd, clockid_t clk, return 0; } -static void do_coarse(const struct vdso_data *vd, clockid_t clk, +static __always_inline void do_coarse(const struct vdso_data *vd, clockid_t clk, struct __kernel_timespec *ts) { const struct vdso_timestamp *vdso_ts = &vd->basetime[clk]; @@ -97,12 +97,16 @@ __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]; +out_hres: + return do_hres(vd, clock, ts); } else if (msk & VDSO_COARSE) { do_coarse(&vd[CS_HRES_COARSE], clock, ts); return 0; } else if (msk & VDSO_RAW) { - return do_hres(&vd[CS_RAW], clock, ts); + vd = &vd[CS_RAW]; + /* goto allows to avoid extra inlining of do_hres. */ + goto out_hres; } return -1; } -- 2.21.0