Date: Wed, 1 Aug 2018 11:08:52 +0000 (UTC) From: Hans Petter Selasky <hselasky@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-10@freebsd.org Subject: svn commit: r337036 - in stable/10/sys: arm/arm sys Message-ID: <201808011108.w71B8qPB085480@repo.freebsd.org>
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Author: hselasky Date: Wed Aug 1 11:08:52 2018 New Revision: 337036 URL: https://svnweb.freebsd.org/changeset/base/337036 Log: MFC r321686 and r330361: Add inline functions to convert between sbintime_t and decimal time units. Use them in some existing code that is vulnerable to roundoff errors. Modified: stable/10/sys/arm/arm/mpcore_timer.c stable/10/sys/sys/time.h Directory Properties: stable/10/ (props changed) Modified: stable/10/sys/arm/arm/mpcore_timer.c ============================================================================== --- stable/10/sys/arm/arm/mpcore_timer.c Wed Aug 1 10:35:49 2018 (r337035) +++ stable/10/sys/arm/arm/mpcore_timer.c Wed Aug 1 11:08:52 2018 (r337036) @@ -349,7 +349,7 @@ attach_et(struct arm_tmr_softc *sc) sc->et.et_flags = ET_FLAGS_PERIODIC | ET_FLAGS_ONESHOT | ET_FLAGS_PERCPU; sc->et.et_quality = 1000; sc->et.et_frequency = sc->clkfreq; - sc->et.et_min_period = 20 * SBT_1NS; + sc->et.et_min_period = nstosbt(20); sc->et.et_max_period = 2 * SBT_1S; sc->et.et_start = arm_tmr_start; sc->et.et_stop = arm_tmr_stop; Modified: stable/10/sys/sys/time.h ============================================================================== --- stable/10/sys/sys/time.h Wed Aug 1 10:35:49 2018 (r337035) +++ stable/10/sys/sys/time.h Wed Aug 1 11:08:52 2018 (r337036) @@ -128,7 +128,7 @@ bintime_shift(struct bintime *_bt, int _exp) #define SBT_1M (SBT_1S * 60) #define SBT_1MS (SBT_1S / 1000) #define SBT_1US (SBT_1S / 1000000) -#define SBT_1NS (SBT_1S / 1000000000) +#define SBT_1NS (SBT_1S / 1000000000) /* beware rounding, see nstosbt() */ #define SBT_MAX 0x7fffffffffffffffLL static __inline int @@ -155,6 +155,53 @@ sbttobt(sbintime_t _sbt) return (_bt); } +/* + * Decimal<->sbt conversions. Multiplying or dividing by SBT_1NS results in + * large roundoff errors which sbttons() and nstosbt() avoid. Millisecond and + * microsecond functions are also provided for completeness. + */ +static __inline int64_t +sbttons(sbintime_t _sbt) +{ + + return ((1000000000 * _sbt) >> 32); +} + +static __inline sbintime_t +nstosbt(int64_t _ns) +{ + + return ((_ns * (((uint64_t)1 << 63) / 500000000)) >> 32); +} + +static __inline int64_t +sbttous(sbintime_t _sbt) +{ + + return ((1000000 * _sbt) >> 32); +} + +static __inline sbintime_t +ustosbt(int64_t _us) +{ + + return ((_us * (((uint64_t)1 << 63) / 500000)) >> 32); +} + +static __inline int64_t +sbttoms(sbintime_t _sbt) +{ + + return ((1000 * _sbt) >> 32); +} + +static __inline sbintime_t +mstosbt(int64_t _ms) +{ + + return ((_ms * (((uint64_t)1 << 63) / 500)) >> 32); +} + /*- * Background information: * @@ -210,7 +257,7 @@ sbttots(sbintime_t _sbt) struct timespec _ts; _ts.tv_sec = _sbt >> 32; - _ts.tv_nsec = ((uint64_t)1000000000 * (uint32_t)_sbt) >> 32; + _ts.tv_nsec = sbttons((uint32_t)_sbt); return (_ts); } @@ -218,8 +265,7 @@ static __inline sbintime_t tstosbt(struct timespec _ts) { - return (((sbintime_t)_ts.tv_sec << 32) + - (_ts.tv_nsec * (((uint64_t)1 << 63) / 500000000) >> 32)); + return (((sbintime_t)_ts.tv_sec << 32) + nstosbt(_ts.tv_nsec)); } static __inline struct timeval @@ -228,7 +274,7 @@ sbttotv(sbintime_t _sbt) struct timeval _tv; _tv.tv_sec = _sbt >> 32; - _tv.tv_usec = ((uint64_t)1000000 * (uint32_t)_sbt) >> 32; + _tv.tv_usec = sbttous((uint32_t)_sbt); return (_tv); } @@ -236,8 +282,7 @@ static __inline sbintime_t tvtosbt(struct timeval _tv) { - return (((sbintime_t)_tv.tv_sec << 32) + - (_tv.tv_usec * (((uint64_t)1 << 63) / 500000) >> 32)); + return (((sbintime_t)_tv.tv_sec << 32) + ustosbt(_tv.tv_usec)); } #endif /* __BSD_VISIBLE */
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