| 1 | /* $Id: RTMpGetArraySize-generic.cpp 98103 2023-01-17 14:15:46Z vboxsync $ */
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| 2 | /** @file
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| 3 | * IPRT - Multiprocessor, Generic RTMpGetArraySize.
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| 4 | */
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| 5 |
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| 6 | /*
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| 7 | * Copyright (C) 2010-2023 Oracle and/or its affiliates.
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| 8 | *
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| 9 | * This file is part of VirtualBox base platform packages, as
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| 10 | * available from https://www.virtualbox.org.
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| 11 | *
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| 12 | * This program is free software; you can redistribute it and/or
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| 13 | * modify it under the terms of the GNU General Public License
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| 14 | * as published by the Free Software Foundation, in version 3 of the
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| 15 | * License.
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| 16 | *
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| 17 | * This program is distributed in the hope that it will be useful, but
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| 18 | * WITHOUT ANY WARRANTY; without even the implied warranty of
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| 19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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| 20 | * General Public License for more details.
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| 21 | *
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| 22 | * You should have received a copy of the GNU General Public License
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| 23 | * along with this program; if not, see <https://www.gnu.org/licenses>.
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| 24 | *
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| 25 | * The contents of this file may alternatively be used under the terms
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| 26 | * of the Common Development and Distribution License Version 1.0
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| 27 | * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
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| 28 | * in the VirtualBox distribution, in which case the provisions of the
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| 29 | * CDDL are applicable instead of those of the GPL.
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| 30 | *
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| 31 | * You may elect to license modified versions of this file under the
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| 32 | * terms and conditions of either the GPL or the CDDL or both.
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| 33 | *
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| 34 | * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
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| 35 | */
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| 36 |
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| 37 |
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| 38 | /*********************************************************************************************************************************
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| 39 | * Header Files *
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| 40 | *********************************************************************************************************************************/
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| 41 | #include <iprt/mp.h>
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| 42 | #include "internal/iprt.h"
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| 43 |
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| 44 | #include <iprt/asm.h>
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| 45 | #include <iprt/cpuset.h>
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| 46 |
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| 47 |
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| 48 | RTDECL(uint32_t) RTMpGetArraySize(void)
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| 49 | {
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| 50 | /*
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| 51 | * Cache the result here. This whole point of this function is that it
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| 52 | * will always return the same value, so that should be safe.
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| 53 | *
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| 54 | * Note! Because RTCPUSET may be to small to represent all the CPUs, we
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| 55 | * check with RTMpGetCount() as well.
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| 56 | */
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| 57 | static uint32_t s_cMaxCpus = 0;
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| 58 | uint32_t cCpus = s_cMaxCpus;
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| 59 | if (RT_UNLIKELY(cCpus == 0))
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| 60 | {
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| 61 | RTCPUSET CpuSet;
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| 62 | uint32_t cCpus1 = RTCpuLastIndex(RTMpGetSet(&CpuSet)) + 1;
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| 63 | uint32_t cCpus2 = RTMpGetCount();
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| 64 | cCpus = RT_MAX(cCpus1, cCpus2);
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| 65 | ASMAtomicCmpXchgU32(&s_cMaxCpus, cCpus, 0);
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| 66 | return cCpus;
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| 67 | }
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| 68 | return s_cMaxCpus;
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| 69 |
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| 70 | }
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| 71 | RT_EXPORT_SYMBOL(RTMpGetArraySize);
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| 72 |
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