2ce59d3a1b
Update adds a general source for retrieving a monotonic time. In addition, AE has been updated to utilize the new monotonic clock for timer processing. This performance improvement is **not** enabled in a default build due to various H/W compatibility concerns, see README.md for details. It does however change the default use of gettimeofday with clock_gettime and somewhat improves performance. This update provides the following 1. An interface for retrieving a monotonic clock. getMonotonicUs returns a uint64_t (aka monotime) with the number of micro-seconds from an arbitrary point. No more messing with tv_sec/tv_usec. Simple routines are provided for measuring elapsed milli-seconds or elapsed micro-seconds (the most common use case for a monotonic timer). No worries about time moving backwards. 2. High-speed assembler implementation for x86 and ARM. The standard method for retrieving the monotonic clock is POSIX.1b (1993): clock_gettime(CLOCK_MONOTONIC, timespec*). However, most modern processors provide a constant speed instruction clock which can be retrieved in a fraction of the time that it takes to call clock_gettime. For x86, this is provided by the RDTSC instruction. For ARM, this is provided by the CNTVCT_EL0 instruction. As a compile-time option, these high-speed timers can be chosen. (Default is POSIX clock_gettime.) 3. Refactor of event loop timers. The timer processing in ae.c has been refactored to use the new monotonic clock interface. This results in simpler/cleaner logic and improved performance.
68 lines
2.2 KiB
C
68 lines
2.2 KiB
C
/*
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* Copyright (c) 2009-2012, Salvatore Sanfilippo <antirez at gmail dot com>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* * Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* * Neither the name of Redis nor the names of its contributors may be used
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* to endorse or promote products derived from this software without
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* specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef _REDIS_FMACRO_H
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#define _REDIS_FMACRO_H
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#define _BSD_SOURCE
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#if defined(__linux__)
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#define _GNU_SOURCE
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#define _DEFAULT_SOURCE
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#endif
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#if defined(_AIX)
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#define _ALL_SOURCE
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#endif
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#if defined(__linux__) || defined(__OpenBSD__)
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#define _XOPEN_SOURCE 700
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/*
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* On NetBSD, _XOPEN_SOURCE undefines _NETBSD_SOURCE and
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* thus hides inet_aton etc.
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*/
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#elif !defined(__NetBSD__)
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#define _XOPEN_SOURCE
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#endif
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#if defined(__sun)
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#define _POSIX_C_SOURCE 199506L
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#endif
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#define _LARGEFILE_SOURCE
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#define _FILE_OFFSET_BITS 64
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#ifdef __linux__
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/* features.h uses the defines above to set feature specific defines. */
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#include <linux/version.h>
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#include <features.h>
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#endif
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#endif
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