efe8b26b82
enabled. The cost of a timecounter read can be quite significant, and the problem became more apparent after r284297, since that change resulted in a call to lockstat_nsecs() for each acquisition of an rwlock read lock. PR: 201642 Reviewed by: avg Tested by: Jason Unovitch MFC after: 3 days Differential Revision: https://reviews.freebsd.org/D3073
66 lines
2.1 KiB
C
66 lines
2.1 KiB
C
/*-
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* Copyright 2008-2009 Stacey Son <sson@FreeBSD.org>
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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 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 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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/*
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* Backend for the lock tracing (lockstat) kernel support. This is required
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* to allow a module to load even though DTrace kernel support may not be
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* present.
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*
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*/
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#ifdef KDTRACE_HOOKS
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#include <sys/time.h>
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#include <sys/types.h>
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#include <sys/lockstat.h>
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/*
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* The following must match the type definition of dtrace_probe. It is
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* defined this way to avoid having to rely on CDDL code.
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*/
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uint32_t lockstat_probemap[LS_NPROBES];
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void (*lockstat_probe_func)(uint32_t, uintptr_t, uintptr_t,
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uintptr_t, uintptr_t, uintptr_t);
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int lockstat_enabled = 0;
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uint64_t
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lockstat_nsecs(void)
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{
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struct bintime bt;
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uint64_t ns;
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if (!lockstat_enabled)
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return (0);
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binuptime(&bt);
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ns = bt.sec * (uint64_t)1000000000;
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ns += ((uint64_t)1000000000 * (uint32_t)(bt.frac >> 32)) >> 32;
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return (ns);
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}
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#endif /* KDTRACE_HOOKS */
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