199fa6015d
zipf is a power law probability distribution. When applied to performance testing of block devices, it will select blocks over the full range of LBAs, but will more frequently select lower-numbered LBAs. The theta parameter governs the distribution - higher values of theta will concentrate the distribution on a smaller number of LBAs. Note that fio supports zipf, so adding it to SPDK will enable our perf tools (bdevperf, nvme-perf) to provide similar functionality. Signed-off-by: Jim Harris <james.r.harris@intel.com> Change-Id: I7df129c9d61996a2070188c6cd9f1fde631ac208 Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/7779 Tested-by: SPDK CI Jenkins <sys_sgci@intel.com> Community-CI: Broadcom CI Community-CI: Mellanox Build Bot Reviewed-by: Ben Walker <benjamin.walker@intel.com> Reviewed-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
84 lines
2.6 KiB
C
84 lines
2.6 KiB
C
/*-
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* BSD LICENSE
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*
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* Copyright (c) Intel Corporation.
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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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*
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* * 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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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* * Neither the name of Intel Corporation nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/** \file
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* Zipf random number distribution
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*/
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#ifndef SPDK_ZIPF_H
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#define SPDK_ZIPF_H
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#include "spdk/stdinc.h"
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#ifdef __cplusplus
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extern "C" {
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#endif
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struct spdk_zipf;
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/**
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* Create a zipf random number generator.
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*
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* Numbers from [0, range) will be returned by the generator when
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* calling \ref spdk_zipf_generate.
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*
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* \param range Range of values for the zipf distribution.
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* \param theta Theta distribution parameter.
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* \param seed Seed value for the random number generator.
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*
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* \return a pointer to the new zipf generator.
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*/
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struct spdk_zipf *spdk_zipf_create(uint64_t range, double theta, uint32_t seed);
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/**
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* Free a zipf generator and set the pointer to NULL.
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*
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* \param zipfp Zipf generator to free.
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*/
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void spdk_zipf_free(struct spdk_zipf **zipfp);
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/**
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* Generate a value from the zipf generator.
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*
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* \param zipf Zipf generator to generate the value from.
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*
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* \return value in the range [0, range)
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*/
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uint64_t spdk_zipf_generate(struct spdk_zipf *zipf);
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#ifdef __cplusplus
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}
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#endif
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#endif
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