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2075553a1b
Although "naive" counting function is not too slow and is smaller, using it on e.g. each of 1024 words of CPU mask feels wrong. function old new delta bb_popcnt_32 - 52 +52 get_prefix 323 321 -2 nproc_main 206 199 -7 d4_run_script 739 731 -8 ipcalc_main 533 507 -26 ------------------------------------------------------------------------------ (add/remove: 2/0 grow/shrink: 0/4 up/down: 52/-43) Total: 9 bytes Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
73 lines
1.7 KiB
C
73 lines
1.7 KiB
C
/*
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* Copyright (C) 2017 Denys Vlasenko <vda.linux@googlemail.com>
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*
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* Licensed under GPLv2, see LICENSE in this source tree
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*/
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//config:config NPROC
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//config: bool "nproc (3.9 kb)"
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//config: default y
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//config: help
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//config: Print number of CPUs
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//applet:IF_NPROC(APPLET_NOFORK(nproc, nproc, BB_DIR_USR_BIN, BB_SUID_DROP, nproc))
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//kbuild:lib-$(CONFIG_NPROC) += nproc.o
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//usage:#define nproc_trivial_usage
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//usage: ""IF_LONG_OPTS("[--all] [--ignore=N]")
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//usage:#define nproc_full_usage "\n\n"
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//usage: "Print number of available CPUs"
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//usage: IF_LONG_OPTS(
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//usage: "\n"
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//usage: "\n --all Number of installed CPUs"
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//usage: "\n --ignore=N Exclude N CPUs"
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//usage: )
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#include "libbb.h"
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int nproc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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int nproc_main(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
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{
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int count = 0;
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#if ENABLE_LONG_OPTS
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int ignore = 0;
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int opts = getopt32long(argv, "\xfe:+",
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"ignore\0" Required_argument "\xfe"
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"all\0" No_argument "\xff"
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, &ignore
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);
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if (opts & (1 << 1)) {
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DIR *cpusd = opendir("/sys/devices/system/cpu");
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if (cpusd) {
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struct dirent *de;
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while (NULL != (de = readdir(cpusd))) {
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char *cpuid = strstr(de->d_name, "cpu");
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if (cpuid && isdigit(cpuid[strlen(cpuid) - 1]))
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count++;
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}
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IF_FEATURE_CLEAN_UP(closedir(cpusd);)
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}
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} else
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#endif
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{
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int i;
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unsigned sz = 2 * 1024;
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unsigned long *mask = get_malloc_cpu_affinity(0, &sz);
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sz /= sizeof(long);
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for (i = 0; i < sz; i++) {
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if (mask[i] != 0) /* most mask[i] are usually 0 */
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count += bb_popcnt_long(mask[i]);
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}
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IF_FEATURE_CLEAN_UP(free(mask);)
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}
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IF_LONG_OPTS(count -= ignore;)
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if (count <= 0)
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count = 1;
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printf("%u\n", count);
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return 0;
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}
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