4e76af6a41
Introduce counter(9) API, that implements fast and raceless counters, provided (but not limited to) for gathering of statistical data. See http://lists.freebsd.org/pipermail/freebsd-arch/2013-April/014204.html for more details. In collaboration with: kib Reviewed by: luigi Tested by: ae, ray Sponsored by: Nginx, Inc.
55 lines
1.9 KiB
C
55 lines
1.9 KiB
C
/*-
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* Copyright (c) 2012 Konstantin Belousov <kib@FreeBSD.org>
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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
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. 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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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* 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 AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#ifndef __MACHINE_COUNTER_H__
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#define __MACHINE_COUNTER_H__
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#include <sys/pcpu.h>
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#ifdef INVARIANTS
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#include <sys/proc.h>
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#endif
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#define counter_enter() critical_enter()
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#define counter_exit() critical_exit()
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#define counter_u64_add_protected(c, inc) do { \
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CRITICAL_ASSERT(curthread); \
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*(uint64_t *)zpcpu_get(c) += (inc); \
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} while (0)
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static inline void
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counter_u64_add(counter_u64_t c, int64_t inc)
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{
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counter_enter();
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counter_u64_add_protected(c, inc);
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counter_exit();
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}
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#endif /* ! __MACHINE_COUNTER_H__ */
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