forked from Minki/linux
64c349f4ae
Performance of get_user_pages_fast() is critical for some workloads, but it's tricky to test it directly. This patch provides /sys/kernel/debug/gup_benchmark that helps with testing performance of it. See tools/testing/selftests/vm/gup_benchmark.c for userspace counterpart. Link: http://lkml.kernel.org/r/20170908215603.9189-2-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Thorsten Leemhuis <regressions@leemhuis.info> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Huang Ying <ying.huang@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
92 lines
1.7 KiB
C
92 lines
1.7 KiB
C
#include <fcntl.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <sys/ioctl.h>
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#include <sys/mman.h>
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#include <sys/prctl.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <linux/types.h>
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#define MB (1UL << 20)
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#define PAGE_SIZE sysconf(_SC_PAGESIZE)
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#define GUP_FAST_BENCHMARK _IOWR('g', 1, struct gup_benchmark)
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struct gup_benchmark {
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__u64 delta_usec;
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__u64 addr;
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__u64 size;
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__u32 nr_pages_per_call;
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__u32 flags;
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};
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int main(int argc, char **argv)
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{
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struct gup_benchmark gup;
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unsigned long size = 128 * MB;
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int i, fd, opt, nr_pages = 1, thp = -1, repeats = 1, write = 0;
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char *p;
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while ((opt = getopt(argc, argv, "m:r:n:tT")) != -1) {
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switch (opt) {
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case 'm':
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size = atoi(optarg) * MB;
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break;
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case 'r':
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repeats = atoi(optarg);
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break;
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case 'n':
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nr_pages = atoi(optarg);
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break;
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case 't':
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thp = 1;
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break;
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case 'T':
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thp = 0;
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break;
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case 'w':
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write = 1;
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default:
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return -1;
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}
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}
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gup.nr_pages_per_call = nr_pages;
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gup.flags = write;
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fd = open("/sys/kernel/debug/gup_benchmark", O_RDWR);
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if (fd == -1)
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perror("open"), exit(1);
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p = mmap(NULL, size, PROT_READ | PROT_WRITE,
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MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
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if (p == MAP_FAILED)
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perror("mmap"), exit(1);
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gup.addr = (unsigned long)p;
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if (thp == 1)
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madvise(p, size, MADV_HUGEPAGE);
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else if (thp == 0)
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madvise(p, size, MADV_NOHUGEPAGE);
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for (; (unsigned long)p < gup.addr + size; p += PAGE_SIZE)
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p[0] = 0;
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for (i = 0; i < repeats; i++) {
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gup.size = size;
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if (ioctl(fd, GUP_FAST_BENCHMARK, &gup))
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perror("ioctl"), exit(1);
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printf("Time: %lld us", gup.delta_usec);
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if (gup.size != size)
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printf(", truncated (size: %lld)", gup.size);
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printf("\n");
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}
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return 0;
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}
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