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In 10.2, the definition of simple_counter resides in the file sync0types.h, not in the file os0sync.h which has been removed.
154 lines
4.4 KiB
C++
154 lines
4.4 KiB
C++
/*****************************************************************************
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Copyright (c) 2012, 2015, Oracle and/or its affiliates. All Rights Reserved.
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Copyright (c) 2017, MariaDB Corporation.
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This program is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free Software
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Foundation; version 2 of the License.
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This program is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
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You should have received a copy of the GNU General Public License along with
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this program; if not, write to the Free Software Foundation, Inc.,
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51 Franklin Street, Suite 500, Boston, MA 02110-1335 USA
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*****************************************************************************/
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/**************************************************//**
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@file include/ut0counter.h
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Counter utility class
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Created 2012/04/12 by Sunny Bains
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*******************************************************/
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#ifndef ut0counter_h
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#define ut0counter_h
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#include <my_rdtsc.h>
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#include "univ.i"
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#include "os0thread.h"
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/** CPU cache line size */
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#ifdef CPU_LEVEL1_DCACHE_LINESIZE
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# define CACHE_LINE_SIZE CPU_LEVEL1_DCACHE_LINESIZE
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#else
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# error CPU_LEVEL1_DCACHE_LINESIZE is undefined
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#endif /* CPU_LEVEL1_DCACHE_LINESIZE */
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/** Default number of slots to use in ib_counter_t */
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#define IB_N_SLOTS 64
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/** Get the offset into the counter array. */
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template <typename Type, int N>
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struct generic_indexer_t {
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/** @return offset within m_counter */
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static size_t offset(size_t index) UNIV_NOTHROW
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{
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return(((index % N) + 1) * (CACHE_LINE_SIZE / sizeof(Type)));
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}
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};
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/** Use the result of my_timer_cycles(), which mainly uses RDTSC for cycles,
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to index into the counter array. See the comments for my_timer_cycles() */
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template <typename Type=ulint, int N=1>
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struct counter_indexer_t : public generic_indexer_t<Type, N> {
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/** @return result from RDTSC or similar functions. */
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static size_t get_rnd_index() UNIV_NOTHROW
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{
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size_t c = static_cast<size_t>(my_timer_cycles());
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if (c != 0) {
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return(c);
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} else {
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/* We may go here if my_timer_cycles() returns 0,
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so we have to have the plan B for the counter. */
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#if !defined(_WIN32)
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return(size_t(os_thread_get_curr_id()));
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#else
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LARGE_INTEGER cnt;
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QueryPerformanceCounter(&cnt);
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return(static_cast<size_t>(cnt.QuadPart));
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#endif /* !_WIN32 */
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}
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}
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/** @return a random offset to the array */
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static size_t get_rnd_offset() UNIV_NOTHROW
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{
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return(generic_indexer_t<Type, N>::offset(get_rnd_index()));
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}
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};
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#define default_indexer_t counter_indexer_t
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/** Class for using fuzzy counters. The counter is not protected by any
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mutex and the results are not guaranteed to be 100% accurate but close
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enough. Creates an array of counters and separates each element by the
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CACHE_LINE_SIZE bytes */
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template <
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typename Type,
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int N = IB_N_SLOTS,
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template<typename, int> class Indexer = default_indexer_t>
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struct MY_ALIGNED(CACHE_LINE_SIZE) ib_counter_t
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{
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#ifdef UNIV_DEBUG
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~ib_counter_t()
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{
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size_t n = (CACHE_LINE_SIZE / sizeof(Type));
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/* Check that we aren't writing outside our defined bounds. */
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for (size_t i = 0; i < UT_ARR_SIZE(m_counter); i += n) {
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for (size_t j = 1; j < n - 1; ++j) {
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ut_ad(m_counter[i + j] == 0);
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}
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}
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}
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#endif /* UNIV_DEBUG */
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/** Increment the counter by 1. */
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void inc() UNIV_NOTHROW { add(1); }
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/** Increment the counter by 1.
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@param[in] index a reasonably thread-unique identifier */
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void inc(size_t index) UNIV_NOTHROW { add(index, 1); }
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/** Add to the counter.
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@param[in] n amount to be added */
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void add(Type n) UNIV_NOTHROW { add(m_policy.get_rnd_offset(), n); }
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/** Add to the counter.
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@param[in] index a reasonably thread-unique identifier
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@param[in] n amount to be added */
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void add(size_t index, Type n) UNIV_NOTHROW {
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size_t i = m_policy.offset(index);
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ut_ad(i < UT_ARR_SIZE(m_counter));
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m_counter[i] += n;
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}
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/* @return total value - not 100% accurate, since it is not atomic. */
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operator Type() const UNIV_NOTHROW {
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Type total = 0;
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for (size_t i = 0; i < N; ++i) {
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total += m_counter[m_policy.offset(i)];
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}
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return(total);
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}
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private:
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/** Indexer into the array */
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Indexer<Type, N>m_policy;
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/** Slot 0 is unused. */
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Type m_counter[(N + 1) * (CACHE_LINE_SIZE / sizeof(Type))];
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};
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#endif /* ut0counter_h */
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