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903bc7dcc2
Both the sysfs and procfs parsing (through GET_NPROCS_PARSER) are removed in favor the syscall. The initial scratch buffer should fit to most of the common usage (1024 bytes with maps to 8192 CPUs). Checked on x86_64-linux-gnu and aarch64-linux-gnu.
42 lines
1.3 KiB
C
42 lines
1.3 KiB
C
/* Copyright (C) 2007-2021 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <sched.h>
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/* Counting bits set, Brian Kernighan's way.
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Using a open-coded routine is slight better for architectures that
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do not have a popcount instruction (compiler might emit a library
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call). */
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static inline int
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countbits (__cpu_mask v)
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{
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int s = 0;
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for (; v != 0; s++)
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v &= v - 1;
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return s;
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}
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int
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__sched_cpucount (size_t setsize, const cpu_set_t *setp)
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{
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int s = 0;
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for (int i = 0; i < setsize / sizeof (__cpu_mask); i++)
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s += countbits (setp->__bits[i]);
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return s;
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}
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libc_hidden_def (__sched_cpucount)
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